diff --git a/src/Escape.php b/src/Escape.php
index 46774e04..0bfe59b7 100644
--- a/src/Escape.php
+++ b/src/Escape.php
@@ -26,15 +26,26 @@ public static function terminal(string $input): string
         );
     }
 
+    /**
+     * Escapes HTML special characters and turns tokens back into raw markup in a single pass.
+     * The escape and token keys are disjoint and strtr never rescans replaced text,
+     * so this equals escaping first and reversing the tokens afterwards.
+     */
+    private const array HTML_MAP = [
+        '&' => '&',
+        '<' => '&lt;',
+        '>' => '&gt;',
+        '"' => '&quot;',
+        '❶' => '&',
+        '❷' => '<',
+        '❸' => '>',
+        '❹' => '"',
+        self::INJECTION_TOKEN => '',
+    ];
+
     public static function html(string $input): string
     {
-        return self::reverse(
-            str_replace(
-                ['&', '<', '>', '"'],
-                ['&amp;', '&lt;', '&gt;', '&quot;'],
-                $input,
-            ),
-        );
+        return strtr($input, self::HTML_MAP);
     }
 
     public static function tokens(string $input): string
@@ -45,13 +56,4 @@ public static function tokens(string $input): string
             $input,
         );
     }
-
-    private static function reverse(string $input): string
-    {
-        return str_replace(
-            self::TOKEN_KEYS,
-            self::TOKEN_VALUES,
-            $input,
-        );
-    }
 }
diff --git a/src/Highlighter.php b/src/Highlighter.php
index 843cf5b6..2ceecbaf 100644
--- a/src/Highlighter.php
+++ b/src/Highlighter.php
@@ -46,7 +46,17 @@
 use Tempest\Highlight\Tokens\GroupTokens;
 use Tempest\Highlight\Tokens\ParseTokens;
 use Tempest\Highlight\Tokens\RenderTokens;
-
+use Tempest\Highlight\Tokens\TokenType;
+use WeakMap;
+
+/**
+ * @phpstan-type LanguageCacheEntry array{
+ *     patterns: array<int|string, array{?string, Pattern, ?TokenType, ?string}>,
+ *     patternRequirements: array<int|string, string[]>,
+ *     before: list<array{Injection, string[]|null}>,
+ *     after: list<array{Injection, string[]|null}>,
+ * }
+ */
 final class Highlighter
 {
     private array $languages = [];
@@ -56,12 +66,18 @@ final class Highlighter
     private readonly ParseTokens $parseTokens;
     private readonly GroupTokens $groupTokens;
     private readonly RenderTokens $renderTokens;
-    private array $patterns = [];
+    /**
+     * Per-language caches, keyed by the language instance itself so entries
+     * are dropped when a language is freed and can never be served to a
+     * different language that reuses its object id. Clones share this map,
+     * which is safe because entries depend only on the language.
+     *
+     * @var WeakMap<Language, LanguageCacheEntry>
+     */
+    private WeakMap $languageCache;
     private array $afterInjections = [];
-    /** @var array<int, Injection[]> */
-    private array $beforeInjectionsCache = [];
-    /** @var array<int, Injection[]> */
-    private array $afterInjectionsCache = [];
+    /** @var array<class-string, string[]|null> */
+    private array $requiredSubstrings = [];
     private ?self $nestedHighlighter = null;
 
     public function __construct(
@@ -105,6 +121,7 @@ public function __construct(
             ->addLanguage(new JsxLanguage())
             ->addLanguage(new TsxLanguage());
 
+        $this->languageCache = new WeakMap();
         $this->parseTokens = new ParseTokens();
         $this->groupTokens = new GroupTokens();
         $this->renderTokens = new RenderTokens($this->theme);
@@ -203,8 +220,14 @@ private function parseContent(string $content, Language $language): string
         $tokens = [];
         $nestedHighlighter = $this->getNestedHighlighter();
 
+        $languageCache = $this->getLanguageCache($language);
+
         // Before Injections
-        foreach ($this->getBeforeInjections($language) as $injection) {
+        foreach ($languageCache['before'] as [$injection, $requiredSubstrings]) {
+            if ($requiredSubstrings !== null && ! $this->containsAny($content, $requiredSubstrings)) {
+                continue;
+            }
+
             $parsedInjection = $injection->parse($content, $nestedHighlighter);
             $content = $parsedInjection->content;
 
@@ -214,9 +237,15 @@ private function parseContent(string $content, Language $language): string
         }
 
         // Patterns
-        foreach (
-            $this->parseTokens->parse($content, $this->getPatterns($language)) as $token
-        ) {
+        $patterns = $languageCache['patterns'];
+
+        foreach ($languageCache['patternRequirements'] as $key => $requiredSubstrings) {
+            if (! $this->containsAny($content, $requiredSubstrings)) {
+                unset($patterns[$key]);
+            }
+        }
+
+        foreach ($this->parseTokens->parseCompiled($content, $patterns) as $token) {
             $tokens[] = $token;
         }
 
@@ -224,9 +253,18 @@ private function parseContent(string $content, Language $language): string
         $content = ($this->renderTokens)($content, $groupedTokens);
 
         // After Injections
-        foreach ($this->getAfterInjections($language) as $injection) {
-            $parsedInjection = $injection->parse($content, $nestedHighlighter);
-            $content = $parsedInjection->content;
+        if (! $this->isNested) {
+            foreach ($languageCache['after'] as [$injection, $requiredSubstrings]) {
+                if ($requiredSubstrings !== null && ! $this->containsAny($content, $requiredSubstrings)) {
+                    continue;
+                }
+
+                $content = $injection->parse($content, $nestedHighlighter)->content;
+            }
+
+            if ($this->gutterInjection instanceof GutterInjection) {
+                $content = $this->gutterInjection->parse($content, $nestedHighlighter)->content;
+            }
         }
 
         if ($this->isNested) {
@@ -237,61 +275,42 @@ private function parseContent(string $content, Language $language): string
     }
 
     /**
-     * @return Injection[]
+     * @return LanguageCacheEntry
      */
-    private function getBeforeInjections(Language $language): array
+    private function getLanguageCache(Language $language): array
     {
-        $languageId = spl_object_id($language);
-
-        if (isset($this->beforeInjectionsCache[$languageId])) {
-            return $this->beforeInjectionsCache[$languageId];
-        }
-
-        $this->buildInjectionCaches($language);
-
-        return $this->beforeInjectionsCache[$languageId];
-    }
-
-    /**
-     * @return Injection[]
-     */
-    private function getAfterInjections(Language $language): array
-    {
-        if ($this->isNested) {
-            return [];
-        }
-
-        $languageId = spl_object_id($language);
-
-        if (! isset($this->afterInjectionsCache[$languageId])) {
-            $this->buildInjectionCaches($language);
-        }
-
-        $afterInjections = $this->afterInjectionsCache[$languageId];
-
-        if ($this->gutterInjection instanceof GutterInjection) {
-            $afterInjections[] = $this->gutterInjection;
+        if (isset($this->languageCache[$language])) {
+            return $this->languageCache[$language];
         }
 
-        return $afterInjections;
-    }
-
-    private function buildInjectionCaches(Language $language): void
-    {
-        $languageId = spl_object_id($language);
         $before = [];
         $after = [];
 
         foreach ($language->getInjections() as $injection) {
             if ($this->isAfterInjection($injection)) {
-                $after[] = $injection;
+                $after[] = [$injection, $this->getRequiredSubstrings($injection)];
             } else {
-                $before[] = $injection;
+                $before[] = [$injection, $this->getRequiredSubstrings($injection)];
+            }
+        }
+
+        $patterns = $this->parseTokens->compile($language->getPatterns());
+        $patternRequirements = [];
+
+        foreach ($patterns as $key => [, $pattern]) {
+            $requiredSubstrings = $this->getRequiredSubstrings($pattern);
+
+            if ($requiredSubstrings !== null) {
+                $patternRequirements[$key] = $requiredSubstrings;
             }
         }
 
-        $this->beforeInjectionsCache[$languageId] = $before;
-        $this->afterInjectionsCache[$languageId] = $after;
+        return $this->languageCache[$language] = [
+            'patterns' => $patterns,
+            'patternRequirements' => $patternRequirements,
+            'before' => $before,
+            'after' => $after,
+        ];
     }
 
     private function normalizeNewline(string $subject): string
@@ -303,13 +322,6 @@ private function normalizeNewline(string $subject): string
         return str_replace(["\r\n", "\r"], "\n", $subject);
     }
 
-    private function getPatterns(Language $language): array
-    {
-        $languageId = spl_object_id($language);
-
-        return $this->patterns[$languageId] ??= $language->getPatterns();
-    }
-
     private function isAfterInjection(Injection $injection): bool
     {
         $class = $injection::class;
@@ -317,4 +329,34 @@ private function isAfterInjection(Injection $injection): bool
         return $this->afterInjections[$class] ??=
             new ReflectionClass($class)->getAttributes(After::class) !== [];
     }
+
+    /**
+     * @return string[]|null
+     */
+    private function getRequiredSubstrings(Injection|Pattern $instance): ?array
+    {
+        $class = $instance::class;
+
+        if (! array_key_exists($class, $this->requiredSubstrings)) {
+            $attribute = new ReflectionClass($class)->getAttributes(RequiresSubstring::class)[0] ?? null;
+
+            $this->requiredSubstrings[$class] = $attribute?->newInstance()->substrings ?: null;
+        }
+
+        return $this->requiredSubstrings[$class];
+    }
+
+    /**
+     * @param string[] $substrings
+     */
+    private function containsAny(string $content, array $substrings): bool
+    {
+        foreach ($substrings as $substring) {
+            if (str_contains($content, $substring)) {
+                return true;
+            }
+        }
+
+        return false;
+    }
 }
diff --git a/src/Languages/Base/Injections/AdditionInjection.php b/src/Languages/Base/Injections/AdditionInjection.php
index a18fa557..8c36402c 100644
--- a/src/Languages/Base/Injections/AdditionInjection.php
+++ b/src/Languages/Base/Injections/AdditionInjection.php
@@ -9,8 +9,10 @@
 use Tempest\Highlight\Highlighter;
 use Tempest\Highlight\Injection;
 use Tempest\Highlight\ParsedInjection;
+use Tempest\Highlight\RequiresSubstring;
 
 #[After]
+#[RequiresSubstring('{+', '+}', "\r")]
 final readonly class AdditionInjection implements Injection
 {
     private const string NEWLINE = "\n";
@@ -22,18 +24,25 @@ public function parse(string $content, Highlighter $highlighter): ParsedInjectio
         $content = str_replace('❷span class=❹ignore❹❸{+❷/span❸', '{+', $content);
         $content = str_replace('❷span class=❹ignore❹❸+}❷/span❸', '+}', $content);
 
-        preg_match_all('/(\{\+)((.|\n)*?)(\+})/', $content, $matches, PREG_OFFSET_CAPTURE);
+        $firstOpener = strpos($content, '{+');
+        $lastCloser = $firstOpener === false ? false : strrpos($content, '+}', $firstOpener);
 
-        $parsedOffset = 0;
+        if ($lastCloser === false) {
+            return new ParsedInjection($content);
+        }
+
+        // No match can end after the last closer, so unclosed openers past it are never rescanned to the end.
+        preg_match_all('/(\{\+)([\s\S]*?)(\+})/', substr($content, 0, $lastCloser + 2), $matches, PREG_OFFSET_CAPTURE);
+
+        $parsedContent = '';
+        $parsedUntil = 0;
+        $startingLineNumber = 1;
+        $linesCountedUntil = 0;
 
         $open = Escape::tokens('<span class="hl-addition">');
         $close = Escape::tokens('</span>');
 
-        foreach ($matches[0] as $match) {
-            $matchedContent = $match[0];
-            $offset = $match[1];
-            $replacementOffset = $offset + $parsedOffset;
-
+        foreach ($matches[0] as [$matchedContent, $offset]) {
             $parsedMatchedContent = str_replace(
                 ['{+', self::NEWLINE, '+}'],
                 [$open, $close . self::NEWLINE . $open, $close],
@@ -41,11 +50,14 @@ public function parse(string $content, Highlighter $highlighter): ParsedInjectio
             );
 
             if (($gutter = $highlighter->getGutterInjection()) instanceof GutterInjection) {
-                $startingLineNumber = substr_count(
+                $startingLineNumber += substr_count(
                     haystack: $content,
                     needle: self::NEWLINE,
-                    length: $replacementOffset,
-                ) + 1;
+                    offset: $linesCountedUntil,
+                    length: $offset - $linesCountedUntil,
+                );
+
+                $linesCountedUntil = $offset;
 
                 $totalAmountOfLines = substr_count(
                     haystack: $parsedMatchedContent,
@@ -59,17 +71,11 @@ public function parse(string $content, Highlighter $highlighter): ParsedInjectio
                 }
             }
 
-            $content = substr_replace(
-                $content,
-                $parsedMatchedContent,
-                $replacementOffset,
-                strlen($matchedContent),
-            );
-
-            $parsedOffset += strlen($parsedMatchedContent) - strlen($matchedContent);
+            $parsedContent .= substr($content, $parsedUntil, $offset - $parsedUntil) . $parsedMatchedContent;
+            $parsedUntil = $offset + strlen($matchedContent);
         }
 
-        return new ParsedInjection($content);
+        return new ParsedInjection($parsedContent . substr($content, $parsedUntil));
     }
 
     private function normalizeLineEndings(string $content): string
diff --git a/src/Languages/Base/Injections/BlurInjection.php b/src/Languages/Base/Injections/BlurInjection.php
index cd7b208e..3126e1b3 100644
--- a/src/Languages/Base/Injections/BlurInjection.php
+++ b/src/Languages/Base/Injections/BlurInjection.php
@@ -6,7 +6,9 @@
 
 use Tempest\Highlight\Injection;
 use Tempest\Highlight\Languages\Base\IsHighlightInjection;
+use Tempest\Highlight\RequiresSubstring;
 
+#[RequiresSubstring('{~')]
 final readonly class BlurInjection implements Injection
 {
     use IsHighlightInjection;
diff --git a/src/Languages/Base/Injections/CustomClassInjection.php b/src/Languages/Base/Injections/CustomClassInjection.php
index 2edb9a72..31241deb 100644
--- a/src/Languages/Base/Injections/CustomClassInjection.php
+++ b/src/Languages/Base/Injections/CustomClassInjection.php
@@ -7,20 +7,27 @@
 use Tempest\Highlight\Highlighter;
 use Tempest\Highlight\Injection;
 use Tempest\Highlight\ParsedInjection;
+use Tempest\Highlight\RequiresSubstring;
 use Tempest\Highlight\Tokens\DynamicTokenType;
 use Tempest\Highlight\Tokens\Token;
 
+#[RequiresSubstring('{:')]
 final readonly class CustomClassInjection implements Injection
 {
     public function parse(string $content, Highlighter $highlighter): ParsedInjection
     {
-        $pattern = '/(?<start>{\:(?<class>[\w-]+)\:)(?<match>(.|\n)*?)(?<end>:})/';
+        $pattern = '/(?<start>{\:(?<class>[\w-]+)\:)(?<match>[\s\S]*?)(?<end>:})/';
 
         $tokens = [];
 
-        preg_match_all($pattern, $content, $matches, PREG_OFFSET_CAPTURE);
+        $firstOpener = strpos($content, '{:');
+        $lastCloser = $firstOpener === false ? false : strrpos($content, ':}', $firstOpener);
+
+        // No match can end after the last closer, so unclosed openers past it are never rescanned to the end.
+        preg_match_all($pattern, $lastCloser === false ? '' : substr($content, 0, $lastCloser + 2), $matches, PREG_OFFSET_CAPTURE);
 
         $additionalOffset = 0;
+        $hasMarkers = true;
 
         foreach (array_keys($matches[0]) as $key) {
             $startToken = $matches['start'][$key][0];
@@ -37,7 +44,12 @@ public function parse(string $content, Highlighter $highlighter): ParsedInjectio
 
             $additionalOffset += strlen($endToken);
 
-            $content = str_replace([$startToken, $endToken], '', $content);
+            if ($hasMarkers) {
+                $content = str_replace([$startToken, $endToken], '', $content);
+
+                // Every start token begins with "{:", so once neither "{:" nor ":}" is left the remaining replacements are no-ops.
+                $hasMarkers = str_contains($content, '{:') || str_contains($content, ':}');
+            }
         }
 
         return new ParsedInjection(
diff --git a/src/Languages/Base/Injections/DeletionInjection.php b/src/Languages/Base/Injections/DeletionInjection.php
index 7b96959e..f2052d1b 100644
--- a/src/Languages/Base/Injections/DeletionInjection.php
+++ b/src/Languages/Base/Injections/DeletionInjection.php
@@ -9,8 +9,10 @@
 use Tempest\Highlight\Highlighter;
 use Tempest\Highlight\Injection;
 use Tempest\Highlight\ParsedInjection;
+use Tempest\Highlight\RequiresSubstring;
 
 #[After]
+#[RequiresSubstring('{-', '-}', "\r")]
 final readonly class DeletionInjection implements Injection
 {
     private const string NEWLINE = "\n";
@@ -22,18 +24,30 @@ public function parse(string $content, Highlighter $highlighter): ParsedInjectio
         $content = str_replace('❷span class=❹ignore❹❸{-❷/span❸', '{-', $content);
         $content = str_replace('❷span class=❹ignore❹❸-}❷/span❸', '-}', $content);
 
-        preg_match_all('/(?<!\{)(\{-)(?!-)((.|\n)*?)(-})(?!})/', $content, $matches, PREG_OFFSET_CAPTURE);
+        $firstOpener = strpos($content, '{-');
+        $lastCloser = $firstOpener === false ? false : strrpos($content, '-}', $firstOpener);
 
-        $parsedOffset = 0;
+        while ($lastCloser !== false && ($content[$lastCloser + 2] ?? '') === '}') {
+            $lastCloser = $lastCloser > 0 ? strrpos($content, '-}', $lastCloser - 1 - strlen($content)) : false;
+        }
+
+        if ($lastCloser === false) {
+            return new ParsedInjection($content);
+        }
+
+        // No match can end after the last valid closer, so unclosed openers past it are never rescanned to the end.
+        // The extra byte keeps the closer's (?!}) lookahead seeing the same character.
+        preg_match_all('/(?<!\{)(\{-)(?!-)([\s\S]*?)(-})(?!})/', substr($content, 0, $lastCloser + 3), $matches, PREG_OFFSET_CAPTURE);
+
+        $parsedContent = '';
+        $parsedUntil = 0;
+        $startingLineNumber = 1;
+        $linesCountedUntil = 0;
 
         $open = Escape::tokens('<span class="hl-deletion">');
         $close = Escape::tokens('</span>');
 
-        foreach ($matches[0] as $match) {
-            $matchedContent = $match[0];
-            $offset = $match[1];
-            $replacementOffset = $offset + $parsedOffset;
-
+        foreach ($matches[0] as [$matchedContent, $offset]) {
             $parsedMatchedContent = str_replace(
                 ['{-', self::NEWLINE, '-}'],
                 [$open, $close . self::NEWLINE . $open, $close],
@@ -41,11 +55,14 @@ public function parse(string $content, Highlighter $highlighter): ParsedInjectio
             );
 
             if (($gutter = $highlighter->getGutterInjection()) instanceof GutterInjection) {
-                $startingLineNumber = substr_count(
+                $startingLineNumber += substr_count(
                     haystack: $content,
                     needle: self::NEWLINE,
-                    length: $replacementOffset,
-                ) + 1;
+                    offset: $linesCountedUntil,
+                    length: $offset - $linesCountedUntil,
+                );
+
+                $linesCountedUntil = $offset;
 
                 $totalAmountOfLines = substr_count(
                     haystack: $parsedMatchedContent,
@@ -59,17 +76,11 @@ public function parse(string $content, Highlighter $highlighter): ParsedInjectio
                 }
             }
 
-            $content = substr_replace(
-                $content,
-                $parsedMatchedContent,
-                $replacementOffset,
-                strlen($matchedContent),
-            );
-
-            $parsedOffset += strlen($parsedMatchedContent) - strlen($matchedContent);
+            $parsedContent .= substr($content, $parsedUntil, $offset - $parsedUntil) . $parsedMatchedContent;
+            $parsedUntil = $offset + strlen($matchedContent);
         }
 
-        return new ParsedInjection($content);
+        return new ParsedInjection($parsedContent . substr($content, $parsedUntil));
     }
 
     private function normalizeLineEndings(string $content): string
diff --git a/src/Languages/Base/Injections/EmphasizeInjection.php b/src/Languages/Base/Injections/EmphasizeInjection.php
index ef079fbd..d29ad1d2 100644
--- a/src/Languages/Base/Injections/EmphasizeInjection.php
+++ b/src/Languages/Base/Injections/EmphasizeInjection.php
@@ -6,7 +6,9 @@
 
 use Tempest\Highlight\Injection;
 use Tempest\Highlight\Languages\Base\IsHighlightInjection;
+use Tempest\Highlight\RequiresSubstring;
 
+#[RequiresSubstring('{_')]
 final readonly class EmphasizeInjection implements Injection
 {
     use IsHighlightInjection;
diff --git a/src/Languages/Base/Injections/GutterInjection.php b/src/Languages/Base/Injections/GutterInjection.php
index f6eae59c..f1f2f476 100644
--- a/src/Languages/Base/Injections/GutterInjection.php
+++ b/src/Languages/Base/Injections/GutterInjection.php
@@ -35,7 +35,18 @@ public function addClass(int $line, string $class): self
 
     public function parse(string $content, Highlighter $highlighter): ParsedInjection
     {
-        $lines = preg_split('/\R/u', trim($content, "\n")) ?? '';
+        $icons = $this->icons;
+        $classes = $this->classes;
+
+        // Marks belong to the parse that added them; a reused highlighter must start the next parse clean.
+        $this->icons = [];
+        $this->classes = [];
+
+        $content = trim($content, "\n");
+
+        // Invalid UTF-8 makes the /u split fail; the fallback matches the same line breaks byte by byte.
+        $lines = preg_split('/\R/u', $content)
+            ?: preg_split('/\r\n|[\n\x0B\x0C\r]|\xC2\x85|\xE2\x80[\xA8\xA9]/', $content);
 
         $gutterNumbers = [];
         $longestGutterNumber = '';
@@ -43,7 +54,7 @@ public function parse(string $content, Highlighter $highlighter): ParsedInjectio
         foreach ($lines as $i => $line) {
             $gutterNumber = $i + $this->startAt;
 
-            if ($icon = ($this->icons[$i + $this->startAt] ?? null)) {
+            if ($icon = ($icons[$i + $this->startAt] ?? null)) {
                 $gutterNumber .= ' ' . $icon;
             }
 
@@ -59,7 +70,7 @@ public function parse(string $content, Highlighter $highlighter): ParsedInjectio
         foreach ($lines as $i => $line) {
             $gutterNumber = $gutterNumbers[$i];
 
-            $hasClasses = $this->classes[$i + $this->startAt] ?? '';
+            $hasClasses = $classes[$i + $this->startAt] ?? '';
             $gutterClass = 'hl-gutter' . ($hasClasses ? ' ' . $hasClasses : '');
 
             $lines[$i] = sprintf(
diff --git a/src/Languages/Base/Injections/StrongInjection.php b/src/Languages/Base/Injections/StrongInjection.php
index 6461479d..e8e1a52e 100644
--- a/src/Languages/Base/Injections/StrongInjection.php
+++ b/src/Languages/Base/Injections/StrongInjection.php
@@ -6,7 +6,9 @@
 
 use Tempest\Highlight\Injection;
 use Tempest\Highlight\Languages\Base\IsHighlightInjection;
+use Tempest\Highlight\RequiresSubstring;
 
+#[RequiresSubstring('{*')]
 final readonly class StrongInjection implements Injection
 {
     use IsHighlightInjection;
diff --git a/src/Languages/Base/IsHighlightInjection.php b/src/Languages/Base/IsHighlightInjection.php
index dd8370c8..66c517a6 100644
--- a/src/Languages/Base/IsHighlightInjection.php
+++ b/src/Languages/Base/IsHighlightInjection.php
@@ -20,9 +20,25 @@ public function parse(string $content, Highlighter $highlighter): ParsedInjectio
     {
         $token = '\\' . $this->getToken();
 
-        $pattern = '/(?<start>{' . $token . ')(?<match>(.|\n)*?)(?<end>' . $token . '})(?!})/';
+        $pattern = '/(?<start>{' . $token . ')(?<match>[\s\S]*?)(?<end>' . $token . '})(?!})/';
 
-        preg_match_all($pattern, $content, $matches, PREG_OFFSET_CAPTURE);
+        $subject = $content;
+        $closer = $this->getToken() . '}';
+
+        // An escaped single non-alphanumeric byte is a literal, so no match can end after the last valid closer
+        // and unclosed openers past it are never rescanned to the end. The extra byte feeds the (?!}) lookahead.
+        if (strlen($closer) === 2 && ! str_contains('0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ', $closer[0])) {
+            $firstOpener = strpos($content, '{' . $this->getToken());
+            $lastCloser = $firstOpener === false ? false : strrpos($content, $closer, $firstOpener);
+
+            while ($lastCloser !== false && ($content[$lastCloser + 2] ?? '') === '}') {
+                $lastCloser = $lastCloser > 0 ? strrpos($content, $closer, $lastCloser - 1 - strlen($content)) : false;
+            }
+
+            $subject = $lastCloser === false ? '' : substr($content, 0, $lastCloser + 3);
+        }
+
+        preg_match_all($pattern, $subject, $matches, PREG_OFFSET_CAPTURE);
 
         $tokens = [];
 
diff --git a/src/Languages/Base/Patterns/AdditionEndTokenPattern.php b/src/Languages/Base/Patterns/AdditionEndTokenPattern.php
index 5807a49a..51bc8a26 100644
--- a/src/Languages/Base/Patterns/AdditionEndTokenPattern.php
+++ b/src/Languages/Base/Patterns/AdditionEndTokenPattern.php
@@ -7,10 +7,12 @@
 use Tempest\Highlight\IsPattern;
 use Tempest\Highlight\Pattern;
 use Tempest\Highlight\PatternTest;
+use Tempest\Highlight\RequiresSubstring;
 use Tempest\Highlight\Tokens\IgnoreTokenType;
 use Tempest\Highlight\Tokens\TokenType;
 
 #[PatternTest('{+ pull_request_target: +}', '+}')]
+#[RequiresSubstring('+}')]
 final readonly class AdditionEndTokenPattern implements Pattern
 {
     use IsPattern;
diff --git a/src/Languages/Base/Patterns/AdditionStartTokenPattern.php b/src/Languages/Base/Patterns/AdditionStartTokenPattern.php
index 8355b1a7..13f1cf42 100644
--- a/src/Languages/Base/Patterns/AdditionStartTokenPattern.php
+++ b/src/Languages/Base/Patterns/AdditionStartTokenPattern.php
@@ -7,10 +7,12 @@
 use Tempest\Highlight\IsPattern;
 use Tempest\Highlight\Pattern;
 use Tempest\Highlight\PatternTest;
+use Tempest\Highlight\RequiresSubstring;
 use Tempest\Highlight\Tokens\IgnoreTokenType;
 use Tempest\Highlight\Tokens\TokenType;
 
 #[PatternTest('{+ pull_request_target: +}', '{+')]
+#[RequiresSubstring('{+')]
 final readonly class AdditionStartTokenPattern implements Pattern
 {
     use IsPattern;
diff --git a/src/Languages/Base/Patterns/DeletionEndTokenPattern.php b/src/Languages/Base/Patterns/DeletionEndTokenPattern.php
index 857c61bf..3850a34b 100644
--- a/src/Languages/Base/Patterns/DeletionEndTokenPattern.php
+++ b/src/Languages/Base/Patterns/DeletionEndTokenPattern.php
@@ -7,12 +7,14 @@
 use Tempest\Highlight\IsPattern;
 use Tempest\Highlight\Pattern;
 use Tempest\Highlight\PatternTest;
+use Tempest\Highlight\RequiresSubstring;
 use Tempest\Highlight\Tokens\IgnoreTokenType;
 use Tempest\Highlight\Tokens\TokenType;
 
 #[PatternTest('{- pull_request_target: -}', '-}')]
 #[PatternTest('{-- pull_request_target: --}', null)]
 #[PatternTest('{{- variable -}}', null)]
+#[RequiresSubstring('-}')]
 final readonly class DeletionEndTokenPattern implements Pattern
 {
     use IsPattern;
diff --git a/src/Languages/Base/Patterns/DeletionStartTokenPattern.php b/src/Languages/Base/Patterns/DeletionStartTokenPattern.php
index 8ed79d37..72b20cd0 100644
--- a/src/Languages/Base/Patterns/DeletionStartTokenPattern.php
+++ b/src/Languages/Base/Patterns/DeletionStartTokenPattern.php
@@ -7,12 +7,14 @@
 use Tempest\Highlight\IsPattern;
 use Tempest\Highlight\Pattern;
 use Tempest\Highlight\PatternTest;
+use Tempest\Highlight\RequiresSubstring;
 use Tempest\Highlight\Tokens\IgnoreTokenType;
 use Tempest\Highlight\Tokens\TokenType;
 
 #[PatternTest('{- pull_request_target: -}', '{-')]
 #[PatternTest('{-- pull_request_target: --}', null)]
 #[PatternTest('{{- variable -}}', null)]
+#[RequiresSubstring('{-')]
 final readonly class DeletionStartTokenPattern implements Pattern
 {
     use IsPattern;
diff --git a/src/Languages/Base/Patterns/InjectionTokenPattern.php b/src/Languages/Base/Patterns/InjectionTokenPattern.php
index d3fc47f9..ea1f1ccf 100644
--- a/src/Languages/Base/Patterns/InjectionTokenPattern.php
+++ b/src/Languages/Base/Patterns/InjectionTokenPattern.php
@@ -7,15 +7,17 @@
 use Tempest\Highlight\Escape;
 use Tempest\Highlight\IsPattern;
 use Tempest\Highlight\Pattern;
+use Tempest\Highlight\RequiresSubstring;
 use Tempest\Highlight\Tokens\TokenTypeEnum;
 
+#[RequiresSubstring(Escape::INJECTION_TOKEN)]
 final readonly class InjectionTokenPattern implements Pattern
 {
     use IsPattern;
 
     public function getPattern(): string
     {
-        return Escape::INJECTION_TOKEN . '(?<match>(.|\n)*?)' . Escape::INJECTION_TOKEN;
+        return Escape::INJECTION_TOKEN . '(?<match>[\s\S]*?)' . Escape::INJECTION_TOKEN;
     }
 
     public function getTokenType(): TokenTypeEnum
diff --git a/src/Languages/Blade/Injections/BladeEchoInjection.php b/src/Languages/Blade/Injections/BladeEchoInjection.php
index d9ab491b..daab067d 100644
--- a/src/Languages/Blade/Injections/BladeEchoInjection.php
+++ b/src/Languages/Blade/Injections/BladeEchoInjection.php
@@ -7,7 +7,9 @@
 use Tempest\Highlight\Highlighter;
 use Tempest\Highlight\Injection;
 use Tempest\Highlight\IsInjection;
+use Tempest\Highlight\RequiresSubstring;
 
+#[RequiresSubstring('{{')]
 final readonly class BladeEchoInjection implements Injection
 {
     use IsInjection;
diff --git a/src/Languages/Blade/Injections/BladeKeywordInjection.php b/src/Languages/Blade/Injections/BladeKeywordInjection.php
index 79ead7b0..5cdda8d7 100644
--- a/src/Languages/Blade/Injections/BladeKeywordInjection.php
+++ b/src/Languages/Blade/Injections/BladeKeywordInjection.php
@@ -7,7 +7,9 @@
 use Tempest\Highlight\Highlighter;
 use Tempest\Highlight\Injection;
 use Tempest\Highlight\IsInjection;
+use Tempest\Highlight\RequiresSubstring;
 
+#[RequiresSubstring('@')]
 final readonly class BladeKeywordInjection implements Injection
 {
     use IsInjection;
diff --git a/src/Languages/Blade/Injections/BladePhpInjection.php b/src/Languages/Blade/Injections/BladePhpInjection.php
index a3bd9bf5..5166a1fb 100644
--- a/src/Languages/Blade/Injections/BladePhpInjection.php
+++ b/src/Languages/Blade/Injections/BladePhpInjection.php
@@ -7,14 +7,17 @@
 use Tempest\Highlight\Highlighter;
 use Tempest\Highlight\Injection;
 use Tempest\Highlight\IsInjection;
+use Tempest\Highlight\RequiresSubstring;
 
+#[RequiresSubstring('@endphp')]
 final readonly class BladePhpInjection implements Injection
 {
     use IsInjection;
 
     public function getPattern(): string
     {
-        return '\@php(?<match>(.|\n)*?)\@endphp';
+        // (*COMMIT) stops the search when an opener has no closer: later openers cannot have one either.
+        return '\@php(*COMMIT)(?<match>[\s\S]*?)\@endphp';
     }
 
     public function parseContent(string $content, Highlighter $highlighter): string
diff --git a/src/Languages/Blade/Injections/BladeRawEchoInjection.php b/src/Languages/Blade/Injections/BladeRawEchoInjection.php
index 85361ca3..52460b5a 100644
--- a/src/Languages/Blade/Injections/BladeRawEchoInjection.php
+++ b/src/Languages/Blade/Injections/BladeRawEchoInjection.php
@@ -7,7 +7,9 @@
 use Tempest\Highlight\Highlighter;
 use Tempest\Highlight\Injection;
 use Tempest\Highlight\IsInjection;
+use Tempest\Highlight\RequiresSubstring;
 
+#[RequiresSubstring('{!!')]
 final readonly class BladeRawEchoInjection implements Injection
 {
     use IsInjection;
diff --git a/src/Languages/Blade/Patterns/BladeCommentPattern.php b/src/Languages/Blade/Patterns/BladeCommentPattern.php
index 7a69df23..df52fc88 100644
--- a/src/Languages/Blade/Patterns/BladeCommentPattern.php
+++ b/src/Languages/Blade/Patterns/BladeCommentPattern.php
@@ -19,7 +19,8 @@
 
     public function getPattern(): string
     {
-        return '(?<match>\{\{\-\-(.|\n)*?\-\-\}\})';
+        // (*COMMIT) stops the search when an opener has no closer: later openers cannot have one either.
+        return '(?<match>\{\{\-\-(?:[\s\S]*?\-\-\}\}|(*COMMIT)(*FAIL)))';
     }
 
     public function getTokenType(): TokenTypeEnum
diff --git a/src/Languages/Css/Patterns/CssCommentPattern.php b/src/Languages/Css/Patterns/CssCommentPattern.php
index af72ec6b..66114fa0 100644
--- a/src/Languages/Css/Patterns/CssCommentPattern.php
+++ b/src/Languages/Css/Patterns/CssCommentPattern.php
@@ -22,7 +22,8 @@
 
     public function getPattern(): string
     {
-        return '/(?<match>\/\*(.|\n)*?\*\/)/m';
+        // (*COMMIT) stops the search when an opener has no closer: later openers cannot have one either.
+        return '/(?<match>\/\*(?:[\s\S]*?\*\/|(*COMMIT)(*FAIL)))/m';
     }
 
     public function getTokenType(): TokenTypeEnum
diff --git a/src/Languages/Diff/Injections/DiffAdditionInjection.php b/src/Languages/Diff/Injections/DiffAdditionInjection.php
index 2e89e2f8..34341308 100644
--- a/src/Languages/Diff/Injections/DiffAdditionInjection.php
+++ b/src/Languages/Diff/Injections/DiffAdditionInjection.php
@@ -8,8 +8,10 @@
 use Tempest\Highlight\Injection;
 use Tempest\Highlight\Languages\Diff\DiffTokenType;
 use Tempest\Highlight\ParsedInjection;
+use Tempest\Highlight\RequiresSubstring;
 use Tempest\Highlight\Tokens\Token;
 
+#[RequiresSubstring('+')]
 class DiffAdditionInjection implements Injection
 {
     public function parse(string $content, Highlighter $highlighter): ParsedInjection
diff --git a/src/Languages/Diff/Injections/DiffDeletionInjection.php b/src/Languages/Diff/Injections/DiffDeletionInjection.php
index bc4b2253..c4c9dfe6 100644
--- a/src/Languages/Diff/Injections/DiffDeletionInjection.php
+++ b/src/Languages/Diff/Injections/DiffDeletionInjection.php
@@ -8,8 +8,10 @@
 use Tempest\Highlight\Injection;
 use Tempest\Highlight\Languages\Diff\DiffTokenType;
 use Tempest\Highlight\ParsedInjection;
+use Tempest\Highlight\RequiresSubstring;
 use Tempest\Highlight\Tokens\Token;
 
+#[RequiresSubstring('-')]
 class DiffDeletionInjection implements Injection
 {
     public function parse(string $content, Highlighter $highlighter): ParsedInjection
diff --git a/src/Languages/Dockerfile/Patterns/DoubleQuoteValuePattern.php b/src/Languages/Dockerfile/Patterns/DoubleQuoteValuePattern.php
index 8dbebe0a..5101e8e9 100644
--- a/src/Languages/Dockerfile/Patterns/DoubleQuoteValuePattern.php
+++ b/src/Languages/Dockerfile/Patterns/DoubleQuoteValuePattern.php
@@ -17,7 +17,7 @@
 
     public function getPattern(): string
     {
-        return '(?<match>"(\\\"|.)*?")';
+        return '(?<match>"(?:[^"\\\\\n]++|\\\\"|\\\\)*+"|"[^\n]*\\\\")';
     }
 
     public function getTokenType(): TokenTypeEnum
diff --git a/src/Languages/Dockerfile/Patterns/SingleQuoteValuePattern.php b/src/Languages/Dockerfile/Patterns/SingleQuoteValuePattern.php
index 3d5e93fc..50226426 100644
--- a/src/Languages/Dockerfile/Patterns/SingleQuoteValuePattern.php
+++ b/src/Languages/Dockerfile/Patterns/SingleQuoteValuePattern.php
@@ -16,7 +16,7 @@
 
     public function getPattern(): string
     {
-        return "(?<match>'(\\\'|.)*?')";
+        return '(?<match>\'(?:[^\'\\\\\n]++|\\\\\'|\\\\)*+\'|\'[^\n]*\\\\\')';
     }
 
     public function getTokenType(): TokenTypeEnum
diff --git a/src/Languages/Ellison/Injections/ParserInjection.php b/src/Languages/Ellison/Injections/ParserInjection.php
index b60adad0..96ef981a 100644
--- a/src/Languages/Ellison/Injections/ParserInjection.php
+++ b/src/Languages/Ellison/Injections/ParserInjection.php
@@ -16,7 +16,7 @@
 
     public function getPattern(): string
     {
-        return '(?<match>(.|\n)*)';
+        return '(?<match>[\s\S]*)';
     }
 
     public function parseContent(string $content, Highlighter $highlighter): string
diff --git a/src/Languages/Gdscript/GdscriptLanguage.php b/src/Languages/Gdscript/GdscriptLanguage.php
index 9e4fd79c..357d2944 100644
--- a/src/Languages/Gdscript/GdscriptLanguage.php
+++ b/src/Languages/Gdscript/GdscriptLanguage.php
@@ -9,11 +9,11 @@
 use Tempest\Highlight\Languages\Gdscript\Patterns\AnnotationPattern;
 use Tempest\Highlight\Languages\Gdscript\Patterns\AsTypePattern;
 use Tempest\Highlight\Languages\Gdscript\Patterns\ClassNamePattern;
+use Tempest\Highlight\Languages\Gdscript\Patterns\CombinedGdscriptKeywordPattern;
 use Tempest\Highlight\Languages\Gdscript\Patterns\DoubleQuoteValuePattern;
 use Tempest\Highlight\Languages\Gdscript\Patterns\ExtendsPattern;
 use Tempest\Highlight\Languages\Gdscript\Patterns\FunctionCallPattern;
 use Tempest\Highlight\Languages\Gdscript\Patterns\FunctionNamePattern;
-use Tempest\Highlight\Languages\Gdscript\Patterns\KeywordPattern;
 use Tempest\Highlight\Languages\Gdscript\Patterns\OperatorPattern;
 use Tempest\Highlight\Languages\Gdscript\Patterns\PropertyAccessPattern;
 use Tempest\Highlight\Languages\Gdscript\Patterns\ReturnTypePattern;
@@ -68,7 +68,6 @@ public function getPatterns(): array
             new OperatorPattern('+'),
             new OperatorPattern('-'),
             new OperatorPattern('*'),
-            new OperatorPattern('/'),
             new OperatorPattern('&'),
             new OperatorPattern('^'),
             new OperatorPattern('|'),
@@ -76,42 +75,44 @@ public function getPatterns(): array
             new OperatorPattern('>'),
             new OperatorPattern('!'),
 
-            new KeywordPattern('if'),
-            new KeywordPattern('elif'),
-            new KeywordPattern('else'),
-            new KeywordPattern('for'),
-            new KeywordPattern('while'),
-            new KeywordPattern('match'),
-            new KeywordPattern('break'),
-            new KeywordPattern('continue'),
-            new KeywordPattern('pass'),
-            new KeywordPattern('return'),
-            new KeywordPattern('class'),
-            new KeywordPattern('class_name'),
-            new KeywordPattern('extends'),
-            new KeywordPattern('is'),
-            new KeywordPattern('not'),
-            new KeywordPattern('and'),
-            new KeywordPattern('or'),
-            new KeywordPattern('in'),
-            new KeywordPattern('as'),
-            new KeywordPattern('self'),
-            new KeywordPattern('signal'),
-            new KeywordPattern('func'),
-            new KeywordPattern('static'),
-            new KeywordPattern('const'),
-            new KeywordPattern('enum'),
-            new KeywordPattern('var'),
-            new KeywordPattern('breakpoint'),
-            new KeywordPattern('preload'),
-            new KeywordPattern('await'),
-            new KeywordPattern('yield'),
-            new KeywordPattern('assert'),
-            new KeywordPattern('super'),
-            new KeywordPattern('PI'),
-            new KeywordPattern('INF'),
-            new KeywordPattern('TAU'),
-            new KeywordPattern('NAN'),
+            new CombinedGdscriptKeywordPattern([
+                'if',
+                'elif',
+                'else',
+                'for',
+                'while',
+                'match',
+                'break',
+                'continue',
+                'pass',
+                'return',
+                'class',
+                'class_name',
+                'extends',
+                'is',
+                'not',
+                'and',
+                'or',
+                'in',
+                'as',
+                'self',
+                'signal',
+                'func',
+                'static',
+                'const',
+                'enum',
+                'var',
+                'breakpoint',
+                'preload',
+                'await',
+                'yield',
+                'assert',
+                'super',
+                'PI',
+                'INF',
+                'TAU',
+                'NAN',
+            ]),
 
             new SinglelineCommentPattern(),
 
diff --git a/src/Languages/Gdscript/Patterns/CombinedGdscriptKeywordPattern.php b/src/Languages/Gdscript/Patterns/CombinedGdscriptKeywordPattern.php
new file mode 100644
index 00000000..7e848a94
--- /dev/null
+++ b/src/Languages/Gdscript/Patterns/CombinedGdscriptKeywordPattern.php
@@ -0,0 +1,50 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tempest\Highlight\Languages\Gdscript\Patterns;
+
+use InvalidArgumentException;
+use Tempest\Highlight\Pattern;
+use Tempest\Highlight\Tokens\TokenTypeEnum;
+
+final readonly class CombinedGdscriptKeywordPattern implements Pattern
+{
+    private string $compiledPattern;
+
+    /**
+     * @param string[] $keywords
+     */
+    public function __construct(array $keywords)
+    {
+        $keywords = array_values(array_unique($keywords));
+
+        if ($keywords === []) {
+            throw new InvalidArgumentException('At least one keyword is required.');
+        }
+
+        usort($keywords, static fn (string $a, string $b): int => strlen($b) <=> strlen($a));
+
+        $alternation = implode(
+            '|',
+            array_map(
+                static fn (string $keyword): string => preg_quote($keyword, '/'),
+                $keywords,
+            ),
+        );
+
+        $this->compiledPattern = "/\b(?<match>(?:{$alternation}))\b/";
+    }
+
+    public function match(string $content): array
+    {
+        preg_match_all($this->compiledPattern, $content, $matches, PREG_OFFSET_CAPTURE);
+
+        return $matches;
+    }
+
+    public function getTokenType(): TokenTypeEnum
+    {
+        return TokenTypeEnum::KEYWORD;
+    }
+}
diff --git a/src/Languages/Gdscript/Patterns/SinglelineCommentPattern.php b/src/Languages/Gdscript/Patterns/SinglelineCommentPattern.php
index 48db0391..f8cb3b3f 100644
--- a/src/Languages/Gdscript/Patterns/SinglelineCommentPattern.php
+++ b/src/Languages/Gdscript/Patterns/SinglelineCommentPattern.php
@@ -16,7 +16,7 @@
 
     public function getPattern(): string
     {
-        return '(?<match>#(.)*)';
+        return '(?<match>#.*)';
     }
 
     public function getTokenType(): TokenTypeEnum
diff --git a/src/Languages/Graphql/Patterns/GraphqlFieldPattern.php b/src/Languages/Graphql/Patterns/GraphqlFieldPattern.php
index 184fbf2e..941ab7df 100644
--- a/src/Languages/Graphql/Patterns/GraphqlFieldPattern.php
+++ b/src/Languages/Graphql/Patterns/GraphqlFieldPattern.php
@@ -16,7 +16,7 @@ final class GraphqlFieldPattern implements Pattern
 
     public function getPattern(): string
     {
-        return '(?<match>[_A-Za-z][_0-9A-Za-z]*)(?=\s*:)';
+        return '(?<![_0-9A-Za-z])[0-9]*+(?<match>[_A-Za-z][_0-9A-Za-z]*+)(?=\s*:)';
     }
 
     public function getTokenType(): TokenTypeEnum
diff --git a/src/Languages/Graphql/Patterns/GraphqlStringPattern.php b/src/Languages/Graphql/Patterns/GraphqlStringPattern.php
index 92ee0f75..40e62849 100644
--- a/src/Languages/Graphql/Patterns/GraphqlStringPattern.php
+++ b/src/Languages/Graphql/Patterns/GraphqlStringPattern.php
@@ -16,7 +16,8 @@ final class GraphqlStringPattern implements Pattern
 
     public function getPattern(): string
     {
-        return '"(?<match>([^"\\\\]|\\\\.)*)"';
+        // An unclosed string would be rescanned from each escaped quote inside it, so skip past it
+        return '"(?<match>(?:[^"\\\\]++|\\\\.)*+)(?:"|(*SKIP)(*FAIL))';
     }
 
     public function getTokenType(): TokenTypeEnum
diff --git a/src/Languages/Html/Injections/CssAttributeInHtmlInjection.php b/src/Languages/Html/Injections/CssAttributeInHtmlInjection.php
index f53a3c38..f786d1e0 100644
--- a/src/Languages/Html/Injections/CssAttributeInHtmlInjection.php
+++ b/src/Languages/Html/Injections/CssAttributeInHtmlInjection.php
@@ -7,14 +7,16 @@
 use Tempest\Highlight\Highlighter;
 use Tempest\Highlight\Injection;
 use Tempest\Highlight\IsInjection;
+use Tempest\Highlight\RequiresSubstring;
 
+#[RequiresSubstring('style="')]
 final readonly class CssAttributeInHtmlInjection implements Injection
 {
     use IsInjection;
 
     public function getPattern(): string
     {
-        return 'style="(?<match>(.|\n)*?)"';
+        return 'style="(?<match>[\s\S]*?)"';
     }
 
     public function parseContent(string $content, Highlighter $highlighter): string
diff --git a/src/Languages/Html/Injections/CssInHtmlInjection.php b/src/Languages/Html/Injections/CssInHtmlInjection.php
index 5f51cabc..0ff96b9a 100644
--- a/src/Languages/Html/Injections/CssInHtmlInjection.php
+++ b/src/Languages/Html/Injections/CssInHtmlInjection.php
@@ -7,14 +7,17 @@
 use Tempest\Highlight\Highlighter;
 use Tempest\Highlight\Injection;
 use Tempest\Highlight\IsInjection;
+use Tempest\Highlight\RequiresSubstring;
 
+#[RequiresSubstring('</style>')]
 final readonly class CssInHtmlInjection implements Injection
 {
     use IsInjection;
 
     public function getPattern(): string
     {
-        return '<style>(?<match>(.|\n)*?)<\/style>';
+        // (*COMMIT) stops the search when an opener has no closer: later openers cannot have one either.
+        return '<style>(*COMMIT)(?<match>[\s\S]*?)<\/style>';
     }
 
     public function parseContent(string $content, Highlighter $highlighter): string
diff --git a/src/Languages/Html/Injections/JavaScriptInHtmlInjection.php b/src/Languages/Html/Injections/JavaScriptInHtmlInjection.php
index ef37d9f8..9eb7ceab 100644
--- a/src/Languages/Html/Injections/JavaScriptInHtmlInjection.php
+++ b/src/Languages/Html/Injections/JavaScriptInHtmlInjection.php
@@ -8,18 +8,24 @@
 use Tempest\Highlight\Injection;
 use Tempest\Highlight\IsInjection;
 use Tempest\Highlight\Languages\JavaScript\JavaScriptLanguage;
+use Tempest\Highlight\RequiresSubstring;
 
+#[RequiresSubstring('</script>')]
 final readonly class JavaScriptInHtmlInjection implements Injection
 {
     use IsInjection;
 
     public function getPattern(): string
     {
-        return '<script>(?<match>(.|\n)*)<\/script>';
+        // (*COMMIT) stops the search when an opener has no closer: later openers cannot have one either.
+        return '<script>(*COMMIT)(?<match>[\s\S]*)<\/script>';
     }
 
     public function parseContent(string $content, Highlighter $highlighter): string
     {
-        return $highlighter->parse($content, new JavaScriptLanguage());
+        // One shared instance, so the highlighter's per-language caches hit on every match
+        static $language = new JavaScriptLanguage();
+
+        return $highlighter->parse($content, $language);
     }
 }
diff --git a/src/Languages/Html/Injections/PhpInHtmlInjection.php b/src/Languages/Html/Injections/PhpInHtmlInjection.php
index 21d34b6b..9acafdd4 100644
--- a/src/Languages/Html/Injections/PhpInHtmlInjection.php
+++ b/src/Languages/Html/Injections/PhpInHtmlInjection.php
@@ -7,14 +7,17 @@
 use Tempest\Highlight\Highlighter;
 use Tempest\Highlight\Injection;
 use Tempest\Highlight\IsInjection;
+use Tempest\Highlight\RequiresSubstring;
 
+#[RequiresSubstring('<?php')]
 final readonly class PhpInHtmlInjection implements Injection
 {
     use IsInjection;
 
     public function getPattern(): string
     {
-        return '\<\?php(?<match>(.|\n)*?)\?>';
+        // (*COMMIT) stops the search when an opener has no closer: later openers cannot have one either.
+        return '\<\?php(*COMMIT)(?<match>[\s\S]*?)\?>';
     }
 
     public function parseContent(string $content, Highlighter $highlighter): string
diff --git a/src/Languages/Html/Injections/PhpShortEchoInHtmlInjection.php b/src/Languages/Html/Injections/PhpShortEchoInHtmlInjection.php
index 845afc59..00508b67 100644
--- a/src/Languages/Html/Injections/PhpShortEchoInHtmlInjection.php
+++ b/src/Languages/Html/Injections/PhpShortEchoInHtmlInjection.php
@@ -7,7 +7,9 @@
 use Tempest\Highlight\Highlighter;
 use Tempest\Highlight\Injection;
 use Tempest\Highlight\IsInjection;
+use Tempest\Highlight\RequiresSubstring;
 
+#[RequiresSubstring('<?=')]
 final readonly class PhpShortEchoInHtmlInjection implements Injection
 {
     use IsInjection;
diff --git a/src/Languages/JavaScript/Injections/JsDocInjection.php b/src/Languages/JavaScript/Injections/JsDocInjection.php
index 717fe07f..d7ab4d86 100644
--- a/src/Languages/JavaScript/Injections/JsDocInjection.php
+++ b/src/Languages/JavaScript/Injections/JsDocInjection.php
@@ -8,18 +8,24 @@
 use Tempest\Highlight\Injection;
 use Tempest\Highlight\IsInjection;
 use Tempest\Highlight\Languages\JavaScript\JsDocLanguage;
+use Tempest\Highlight\RequiresSubstring;
 
+#[RequiresSubstring('/**')]
 final readonly class JsDocInjection implements Injection
 {
     use IsInjection;
 
     public function getPattern(): string
     {
-        return '/(?<match>\/\*\*(.|\n)*?\*\/)/m';
+        // (*COMMIT) stops the search when an opener has no closer: later openers cannot have one either.
+        return '/(?<match>\/\*\*(*COMMIT)[\s\S]*?\*\/)/m';
     }
 
     public function parseContent(string $content, Highlighter $highlighter): string
     {
-        return $highlighter->parse($content, new JsDocLanguage());
+        // One shared instance, so the highlighter's per-language caches hit on every match
+        static $language = new JsDocLanguage();
+
+        return $highlighter->parse($content, $language);
     }
 }
diff --git a/src/Languages/JavaScript/Patterns/JsDoubleQuoteValuePattern.php b/src/Languages/JavaScript/Patterns/JsDoubleQuoteValuePattern.php
index 98e9eec9..2a29b69a 100644
--- a/src/Languages/JavaScript/Patterns/JsDoubleQuoteValuePattern.php
+++ b/src/Languages/JavaScript/Patterns/JsDoubleQuoteValuePattern.php
@@ -19,7 +19,7 @@
 
     public function getPattern(): string
     {
-        return '(?<match>"(\\\"|.)*?")';
+        return '(?<match>"(?:[^"\\\\\n]++|\\\\"|\\\\)*+"|"[^\n]*\\\\")';
     }
 
     public function getTokenType(): TokenTypeEnum
diff --git a/src/Languages/JavaScript/Patterns/JsMultilineCommentPattern.php b/src/Languages/JavaScript/Patterns/JsMultilineCommentPattern.php
index 51a43500..20197668 100644
--- a/src/Languages/JavaScript/Patterns/JsMultilineCommentPattern.php
+++ b/src/Languages/JavaScript/Patterns/JsMultilineCommentPattern.php
@@ -23,7 +23,8 @@
 
     public function getPattern(): string
     {
-        return '/(?<match>\/\*(.|\n)*?\*\/)/m';
+        // (*COMMIT) stops the search when an opener has no closer: later openers cannot have one either.
+        return '/(?<match>\/\*(?:[\s\S]*?\*\/|(*COMMIT)(*FAIL)))/m';
     }
 
     public function getTokenType(): TokenTypeEnum
diff --git a/src/Languages/JavaScript/Patterns/JsSingleQuoteValuePattern.php b/src/Languages/JavaScript/Patterns/JsSingleQuoteValuePattern.php
index c2630f62..6cb7b707 100644
--- a/src/Languages/JavaScript/Patterns/JsSingleQuoteValuePattern.php
+++ b/src/Languages/JavaScript/Patterns/JsSingleQuoteValuePattern.php
@@ -19,7 +19,7 @@
 
     public function getPattern(): string
     {
-        return "(?<match>'(\\\'|.)*?')";
+        return '(?<match>\'(?:[^\'\\\\\n]++|\\\\\'|\\\\)*+\'|\'[^\n]*\\\\\')';
     }
 
     public function getTokenType(): TokenTypeEnum
diff --git a/src/Languages/JavaScript/Patterns/JsSinglelineCommentPattern.php b/src/Languages/JavaScript/Patterns/JsSinglelineCommentPattern.php
index 2a1e08f3..bf5760fe 100644
--- a/src/Languages/JavaScript/Patterns/JsSinglelineCommentPattern.php
+++ b/src/Languages/JavaScript/Patterns/JsSinglelineCommentPattern.php
@@ -16,7 +16,7 @@
 
     public function getPattern(): string
     {
-        return '(?<match>\/\/(.)*)';
+        return '(?<match>\/\/.*)';
     }
 
     public function getTokenType(): TokenTypeEnum
diff --git a/src/Languages/Php/Injections/PhpAttributeInstanceInjection.php b/src/Languages/Php/Injections/PhpAttributeInstanceInjection.php
index e2f487b1..6f71edae 100644
--- a/src/Languages/Php/Injections/PhpAttributeInstanceInjection.php
+++ b/src/Languages/Php/Injections/PhpAttributeInstanceInjection.php
@@ -8,15 +8,18 @@
 use Tempest\Highlight\Highlighter;
 use Tempest\Highlight\Injection;
 use Tempest\Highlight\IsInjection;
+use Tempest\Highlight\RequiresSubstring;
 use Tempest\Highlight\Tokens\TokenTypeEnum;
 
+#[RequiresSubstring('#[')]
 final readonly class PhpAttributeInstanceInjection implements Injection
 {
     use IsInjection;
 
     public function getPattern(): string
     {
-        return '(?<match>\#\[[\w]+\((.|\n)*?\)\])';
+        // (*COMMIT) stops the search when an opener has no closer: later openers cannot have one either.
+        return '(?<match>\#\[[\w]+\((*COMMIT)[\s\S]*?\)\])';
     }
 
     public function parseContent(string $content, Highlighter $highlighter): string
diff --git a/src/Languages/Php/Injections/PhpAttributePlainInjection.php b/src/Languages/Php/Injections/PhpAttributePlainInjection.php
index 401a01b2..73943460 100644
--- a/src/Languages/Php/Injections/PhpAttributePlainInjection.php
+++ b/src/Languages/Php/Injections/PhpAttributePlainInjection.php
@@ -8,8 +8,10 @@
 use Tempest\Highlight\Highlighter;
 use Tempest\Highlight\Injection;
 use Tempest\Highlight\IsInjection;
+use Tempest\Highlight\RequiresSubstring;
 use Tempest\Highlight\Tokens\TokenTypeEnum;
 
+#[RequiresSubstring('#[')]
 final readonly class PhpAttributePlainInjection implements Injection
 {
     use IsInjection;
diff --git a/src/Languages/Php/Injections/PhpDocCommentInjection.php b/src/Languages/Php/Injections/PhpDocCommentInjection.php
index b4e87129..1238f86c 100644
--- a/src/Languages/Php/Injections/PhpDocCommentInjection.php
+++ b/src/Languages/Php/Injections/PhpDocCommentInjection.php
@@ -8,14 +8,17 @@
 use Tempest\Highlight\Injection;
 use Tempest\Highlight\IsInjection;
 use Tempest\Highlight\Languages\Php\PhpDocCommentLanguage;
+use Tempest\Highlight\RequiresSubstring;
 
+#[RequiresSubstring('/**')]
 final readonly class PhpDocCommentInjection implements Injection
 {
     use IsInjection;
 
     public function getPattern(): string
     {
-        return '/(?<match>\/\*\*(.|\n)*?\*\/)/m';
+        // (*COMMIT) stops the search when an opener has no closer: later openers cannot have one either.
+        return '/(?<match>\/\*\*(*COMMIT)[\s\S]*?\*\/)/m';
     }
 
     public function parseContent(string $content, Highlighter $highlighter): string
diff --git a/src/Languages/Php/Injections/PhpFunctionParametersInjection.php b/src/Languages/Php/Injections/PhpFunctionParametersInjection.php
index 9be18ec9..96159f1d 100644
--- a/src/Languages/Php/Injections/PhpFunctionParametersInjection.php
+++ b/src/Languages/Php/Injections/PhpFunctionParametersInjection.php
@@ -9,14 +9,17 @@
 use Tempest\Highlight\Injection;
 use Tempest\Highlight\IsInjection;
 use Tempest\Highlight\Languages\Php\PhpTypeLanguage;
+use Tempest\Highlight\RequiresSubstring;
 
+#[RequiresSubstring('function', 'fn')]
 final readonly class PhpFunctionParametersInjection implements Injection
 {
     use IsInjection;
 
     public function getPattern(): string
     {
-        return '(function|fn)[\s\w]*\((?<match>(.|\n)*?)(use\s*\(|{|\)[\s]*({|;|:|=>))';
+        // (*COMMIT) stops the search when an opener has no closer: later openers cannot have one either.
+        return '(function|fn)[\s\w]*\((*COMMIT)(?<match>[\s\S]*?)(use\s*\(|{|\)[\s]*({|;|:|=>))';
     }
 
     public function parseContent(string $content, Highlighter $highlighter): string
diff --git a/src/Languages/Php/Injections/PhpGenericTypeInjection.php b/src/Languages/Php/Injections/PhpGenericTypeInjection.php
index 20339de9..ca82ca75 100644
--- a/src/Languages/Php/Injections/PhpGenericTypeInjection.php
+++ b/src/Languages/Php/Injections/PhpGenericTypeInjection.php
@@ -8,8 +8,10 @@
 use Tempest\Highlight\Highlighter;
 use Tempest\Highlight\Injection;
 use Tempest\Highlight\ParsedInjection;
+use Tempest\Highlight\RequiresSubstring;
 use Tempest\Highlight\Tokens\TokenTypeEnum;
 
+#[RequiresSubstring('@template', '<')]
 final readonly class PhpGenericTypeInjection implements Injection
 {
     public function parse(string $content, Highlighter $highlighter): ParsedInjection
@@ -28,18 +30,23 @@ public function parse(string $content, Highlighter $highlighter): ParsedInjectio
             $genericTypes[$genericMatch] = $genericMatch;
         }
 
-        $theme = $highlighter->getTheme();
-
-        foreach ($genericTypes as $genericType) {
-            $content = preg_replace(
-                '/\b' . $genericType . '\b/',
-                Escape::tokens($theme->before(TokenTypeEnum::GENERIC))
-                . $genericType
-                . Escape::tokens($theme->after(TokenTypeEnum::GENERIC)),
-                (string) $content,
-            );
+        if ($genericTypes === []) {
+            return new ParsedInjection($content);
         }
 
+        $theme = $highlighter->getTheme();
+        $before = Escape::tokens($theme->before(TokenTypeEnum::GENERIC));
+        $after = Escape::tokens($theme->after(TokenTypeEnum::GENERIC));
+
+        // One constant pattern instead of one per type name: user-derived patterns would churn PHP's regex cache
+        $content = preg_replace_callback(
+            '/\w+/',
+            fn (array $match): string => isset($genericTypes[$match[0]])
+                ? $before . $match[0] . $after
+                : $match[0],
+            $content,
+        );
+
         return new ParsedInjection($content);
     }
 }
diff --git a/src/Languages/Php/Injections/PhpHeredocInjection.php b/src/Languages/Php/Injections/PhpHeredocInjection.php
index 56293425..2856acd7 100644
--- a/src/Languages/Php/Injections/PhpHeredocInjection.php
+++ b/src/Languages/Php/Injections/PhpHeredocInjection.php
@@ -8,8 +8,10 @@
 use Tempest\Highlight\Highlighter;
 use Tempest\Highlight\Injection;
 use Tempest\Highlight\ParsedInjection;
+use Tempest\Highlight\RequiresSubstring;
 use Tempest\Highlight\Tokens\TokenTypeEnum;
 
+#[RequiresSubstring('<<<')]
 final readonly class PhpHeredocInjection implements Injection
 {
     public function parse(string $content, Highlighter $highlighter): ParsedInjection
@@ -21,8 +23,24 @@ public function parse(string $content, Highlighter $highlighter): ParsedInjectio
 
         // First we'll search for all Heredoc open tags,
         // which we need in order to find the close tag, and so the whole Heredoc block
+        $unmatched = [];
+
         foreach ($languageMatches['language'] as $language) {
-            preg_match_all('/<<<' . $language . '(?<match>(.|\n)*?)' . $language . '(?:;|\s|\))/', $content, $matches);
+            // Content only changes when a tag matches, so a tag that found nothing finds nothing again until then
+            if (isset($unmatched[$language])) {
+                continue;
+            }
+
+            // (*COMMIT) stops the search when an opener has no closer: later openers cannot have one either.
+            preg_match_all('/<<<' . $language . '(*COMMIT)(?<match>[\s\S]*?)' . $language . '(?:;|\s|\))/', $content, $matches);
+
+            if ($matches['match'] === []) {
+                $unmatched[$language] = true;
+
+                continue;
+            }
+
+            $unmatched = [];
 
             foreach ($matches['match'] as $key => $match) {
                 $fullMatch = $matches[0][$key];
diff --git a/src/Languages/Php/Patterns/CombinedKeywordPattern.php b/src/Languages/Php/Patterns/CombinedKeywordPattern.php
index bf58b3e2..ba09ba8d 100644
--- a/src/Languages/Php/Patterns/CombinedKeywordPattern.php
+++ b/src/Languages/Php/Patterns/CombinedKeywordPattern.php
@@ -37,7 +37,7 @@ public function __construct(
 
         $flags = $this->caseInsensitive ? 'i' : '';
 
-        $this->compiledPattern = "/\b(?<!\$)(?<!->)(?<match>(?:{$alternation}))(\$|,|\)|;|:|\s|\()/{$flags}";
+        $this->compiledPattern = "/\b(?<!\\$)(?<!->)(?<match>(?:{$alternation}))(\$|,|\)|;|:|\s|\()/{$flags}";
     }
 
     public function match(string $content): array
diff --git a/src/Languages/Php/Patterns/DoubleQuoteValuePattern.php b/src/Languages/Php/Patterns/DoubleQuoteValuePattern.php
index eadadee1..40a77034 100644
--- a/src/Languages/Php/Patterns/DoubleQuoteValuePattern.php
+++ b/src/Languages/Php/Patterns/DoubleQuoteValuePattern.php
@@ -19,7 +19,7 @@
 
     public function getPattern(): string
     {
-        return '(?<match>"(\\\"|.)*?")';
+        return '(?<match>"(?:[^"\\\\\n]++|\\\\"|\\\\)*+"|"[^\n]*\\\\")';
     }
 
     public function getTokenType(): TokenTypeEnum
diff --git a/src/Languages/Php/Patterns/MultilineSingleDocCommentPattern.php b/src/Languages/Php/Patterns/MultilineSingleDocCommentPattern.php
index 73c23f75..3d27f3ee 100644
--- a/src/Languages/Php/Patterns/MultilineSingleDocCommentPattern.php
+++ b/src/Languages/Php/Patterns/MultilineSingleDocCommentPattern.php
@@ -14,7 +14,8 @@
 
     public function getPattern(): string
     {
-        return '/(?<match>\/\*(.|\n)*?\*\/)/m';
+        // (*COMMIT) stops the search when an opener has no closer: later openers cannot have one either.
+        return '/(?<match>\/\*(?:[\s\S]*?\*\/|(*COMMIT)(*FAIL)))/m';
     }
 
     public function getTokenType(): TokenTypeEnum
diff --git a/src/Languages/Php/Patterns/OperatorPattern.php b/src/Languages/Php/Patterns/OperatorPattern.php
index c7b4526a..501582a3 100644
--- a/src/Languages/Php/Patterns/OperatorPattern.php
+++ b/src/Languages/Php/Patterns/OperatorPattern.php
@@ -12,7 +12,7 @@ final class OperatorPattern implements Pattern
 {
     use IsPattern;
 
-    public function __construct(private string $operator)
+    public function __construct(private readonly string $operator)
     {
     }
 
diff --git a/src/Languages/Php/Patterns/SingleQuoteValuePattern.php b/src/Languages/Php/Patterns/SingleQuoteValuePattern.php
index e6246467..4ce7af49 100644
--- a/src/Languages/Php/Patterns/SingleQuoteValuePattern.php
+++ b/src/Languages/Php/Patterns/SingleQuoteValuePattern.php
@@ -27,7 +27,7 @@
 
     public function getPattern(): string
     {
-        return "(?<match>'(\\\'|.)*?')";
+        return '(?<match>\'(?:[^\'\\\\\n]++|\\\\\'|\\\\)*+\'|\'[^\n]*\\\\\')';
     }
 
     public function getTokenType(): TokenTypeEnum
diff --git a/src/Languages/Php/Patterns/SinglelineCommentPattern.php b/src/Languages/Php/Patterns/SinglelineCommentPattern.php
index 5b1dd0c9..d328f377 100644
--- a/src/Languages/Php/Patterns/SinglelineCommentPattern.php
+++ b/src/Languages/Php/Patterns/SinglelineCommentPattern.php
@@ -14,7 +14,7 @@
 
     public function getPattern(): string
     {
-        return '(?<match>(?:\/\/|#[^\[])(.)*)';
+        return '(?<match>(?:\/\/|#[^\[]).*)';
     }
 
     public function getTokenType(): TokenTypeEnum
diff --git a/src/Languages/Php/Patterns/StaticClassCallPattern.php b/src/Languages/Php/Patterns/StaticClassCallPattern.php
index 1271aeff..1a3fddc0 100644
--- a/src/Languages/Php/Patterns/StaticClassCallPattern.php
+++ b/src/Languages/Php/Patterns/StaticClassCallPattern.php
@@ -18,7 +18,7 @@
 
     public function getPattern(): string
     {
-        return '(?<!\\$)(?<match>[\\\\\w]+)\:\:';
+        return '(?:(?<=\\$)[\\\\\w]|(?<![\\\\\w$]))(?<match>[\\\\\w]+)\:\:';
     }
 
     public function getTokenType(): TokenTypeEnum
diff --git a/src/Languages/Python/Patterns/PyCaseWildcardPattern.php b/src/Languages/Python/Patterns/PyCaseWildcardPattern.php
new file mode 100644
index 00000000..0198e931
--- /dev/null
+++ b/src/Languages/Python/Patterns/PyCaseWildcardPattern.php
@@ -0,0 +1,287 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tempest\Highlight\Languages\Python\Patterns;
+
+use Tempest\Highlight\Pattern;
+use Tempest\Highlight\PatternTest;
+use Tempest\Highlight\RequiresSubstring;
+use Tempest\Highlight\Tokens\TokenTypeEnum;
+
+#[PatternTest(input: 'case _:', output: '_')]
+#[PatternTest(input: "match x:\n    case [y, *_] if _:\n        return _", output: '_')]
+#[PatternTest(input: "if x:\n    case _:", output: null)]
+#[PatternTest(input: "# Special case\n_: int = 1", output: null)]
+#[RequiresSubstring('case')]
+final readonly class PyCaseWildcardPattern implements Pattern
+{
+    /**
+     * Finds `_` wildcards in the patterns of `case` clauses whose enclosing block is a `match` statement (or the snippet's top level).
+     */
+    public function match(string $content): array
+    {
+        if (! preg_match('/(?:^|(?<=[\r\n]))[ \t\f]*+case(?![\w\x80-\xff])/', $content)) {
+            return ['match' => []];
+        }
+
+        $strings = $this->multiLineStrings($content);
+        $string = 0;
+        $wildcards = [];
+        $blocks = [];
+        $scannedUntil = 0;
+        $length = strlen($content);
+        $lineStart = 0;
+
+        while ($lineStart < $length) {
+            while (isset($strings[$string]) && $strings[$string][1] <= $lineStart) {
+                $string++;
+            }
+
+            $insideString = ($strings[$string][0] ?? $lineStart) < $lineStart;
+
+            // Lines that continue an earlier header, clause or string are not statements and do not affect indentation
+            if ($insideString || $lineStart < $scannedUntil) {
+                $lineStart = $this->nextLine($content, max($scannedUntil, $insideString ? $strings[$string][1] : 0));
+
+                continue;
+            }
+
+            $indentLength = strspn($content, " \t\f", $lineStart);
+            $first = $lineStart + $indentLength;
+
+            if (str_contains("#\r\n", $content[$first] ?? "\n")) {
+                $lineStart = $this->nextLine($content, $first);
+
+                continue;
+            }
+
+            $indent = $this->indentWidth(substr($content, $lineStart, $indentLength));
+
+            while ($blocks !== [] && $blocks[array_key_last($blocks)][0] >= $indent) {
+                array_pop($blocks);
+            }
+
+            $enclosedByMatch = $blocks === [] || $blocks[array_key_last($blocks)][1];
+            $isMatchHeader = false;
+
+            if (preg_match('/\G(?:match|case)(?![\w\x80-\xff])/', $content, $keyword, 0, $first)) {
+                [$scannedUntil, $isStatement, $clauseWildcards] = $this->scan($content, $first + strlen($keyword[0]), $keyword[0] === 'case');
+
+                if ($keyword[0] === 'match') {
+                    $isMatchHeader = $isStatement;
+                } elseif ($isStatement && $enclosedByMatch) {
+                    array_push($wildcards, ...$clauseWildcards);
+                }
+            }
+
+            $blocks[] = [$indent, $isMatchHeader];
+            $lineStart = $this->nextLine($content, max($first, $scannedUntil));
+        }
+
+        return ['match' => $wildcards];
+    }
+
+    public function getTokenType(): TokenTypeEnum
+    {
+        return TokenTypeEnum::KEYWORD;
+    }
+
+    /**
+     * Scans a `match` or `case` header from just after its keyword up to its top-level colon.
+     *
+     * @return array{int, bool, array<int, array{string, int}>}
+     */
+    private function scan(string $content, int $index, bool $inPattern): array
+    {
+        $index += strspn($content, " \t\f", $index);
+
+        if (str_contains("=.:)]},#\r\n", $content[$index] ?? "\n")) {
+            return [$index, false, []];
+        }
+
+        $length = strlen($content);
+        $depth = 0;
+        $previous = '';
+        $wildcards = [];
+
+        while ($index < $length) {
+            $char = $content[$index];
+
+            if ($char === ' ' || $char === "\t" || $char === "\f") {
+                $index++;
+
+                continue;
+            }
+
+            if ($char === "\n" || $char === "\r") {
+                if ($depth === 0) {
+                    return [$index, false, []];
+                }
+
+                $index++;
+
+                continue;
+            }
+
+            if ($char === '#') {
+                $index += strcspn($content, "\r\n", $index);
+
+                continue;
+            }
+
+            if ($char === '\\') {
+                $index = $this->skipEscape($content, $index);
+
+                continue;
+            }
+
+            if ($char === ':' && $depth === 0) {
+                return [$index, true, $wildcards];
+            }
+
+            if ($char === '"' || $char === "'") {
+                $index = $this->skipString($content, $index);
+                $previous = '"';
+
+                continue;
+            }
+
+            if (preg_match('/\G[\w\x80-\xff]+/', $content, $word, 0, $index)) {
+                $word = $word[0];
+                $next = $index + strlen($word);
+
+                if (($content[$next] ?? '') === '"' || ($content[$next] ?? '') === "'") {
+                    if (preg_match('/^[rbuft]{1,2}$/i', $word)) {
+                        $index = $this->skipString($content, $next);
+                        $previous = '"';
+
+                        continue;
+                    }
+                }
+
+                if ($word === 'if' && $depth === 0) {
+                    $inPattern = false;
+                } elseif ($inPattern && $word === '_' && $previous !== '.' && ! preg_match('/\G[ \t\f]*(?:=(?!=)|\.)/', $content, $nameOrAttribute, 0, $next)) {
+                    $wildcards[] = ['_', $index];
+                }
+
+                $index = $next;
+                $previous = 'a';
+
+                continue;
+            }
+
+            // A pattern never assigns, calls or subscripts at the top level, so this is an ordinary statement using `case` as a name
+            if ($inPattern && $depth === 0 && (
+                ($char === '=' && $previous !== '=' && ($content[$index + 1] ?? '') !== '=')
+                || (($char === '(' || $char === '[') && in_array($previous, [')', ']', '}'], true))
+            )) {
+                return [$index, false, []];
+            }
+
+            if ($char === '(' || $char === '[' || $char === '{') {
+                $depth++;
+            } elseif ($char === ')' || $char === ']' || $char === '}') {
+                $depth = max(0, $depth - 1);
+            }
+
+            $previous = $char;
+            $index++;
+        }
+
+        return [$index, false, []];
+    }
+
+    /**
+     * @return array<int, array{int, int}> start and end offsets of the strings that span several lines
+     */
+    private function multiLineStrings(string $content): array
+    {
+        // Comments and single-line strings are skipped, so only strings that may span lines are returned
+        preg_match_all(
+            <<<'REGEX'
+            /
+                (?: \#[^\r\n]*+
+                  | "(?!"")(?:[^"\\\r\n]++|\\[^\r\n])*+(?:"|(?=[\r\n]|\z))
+                  | '(?!'')(?:[^'\\\r\n]++|\\[^\r\n])*+(?:'|(?=[\r\n]|\z))
+                ) (*SKIP)(*FAIL)
+              | """(?:[^"\\]++|\\[\s\S]?|"(?!""))*+(?:"""|\z)
+              | '''(?:[^'\\]++|\\[\s\S]?|'(?!''))*+(?:'''|\z)
+              | "(?:[^"\\\r\n]++|\\[\s\S]?)*+"?
+              | '(?:[^'\\\r\n]++|\\[\s\S]?)*+'?
+            /x
+            REGEX,
+            $content,
+            $tokens,
+            PREG_OFFSET_CAPTURE,
+        );
+
+        $strings = [];
+
+        foreach ($tokens[0] as [$token, $offset]) {
+            if (strpbrk($token, "\r\n") !== false) {
+                $strings[] = [$offset, $offset + strlen($token)];
+            }
+        }
+
+        return $strings;
+    }
+
+    private function skipString(string $content, int $index): int
+    {
+        $quote = $content[$index];
+        $delimiter = substr($content, $index, 3) === $quote . $quote . $quote ? $quote . $quote . $quote : $quote;
+        $index += strlen($delimiter);
+        $length = strlen($content);
+
+        while ($index < $length) {
+            $index += strcspn($content, "\\\r\n" . $quote, $index);
+            $char = $content[$index] ?? '';
+
+            if ($char === '\\') {
+                $index = $this->skipEscape($content, $index);
+            } elseif ($char !== $quote) {
+                // An unterminated single-line string ends at the newline
+                if ($delimiter === $quote) {
+                    return $index;
+                }
+
+                $index++;
+            } elseif (substr_compare($content, $delimiter, $index, strlen($delimiter)) === 0) {
+                return $index + strlen($delimiter);
+            } else {
+                $index++;
+            }
+        }
+
+        return $length;
+    }
+
+    private function nextLine(string $content, int $offset): int
+    {
+        $offset += strcspn($content, "\r\n", $offset);
+
+        return $offset + (substr($content, $offset, 2) === "\r\n" ? 2 : 1);
+    }
+
+    private function skipEscape(string $content, int $index): int
+    {
+        return $index + (substr_compare($content, "\\\r\n", $index, 3) === 0 ? 3 : 2);
+    }
+
+    private function indentWidth(string $indentation): int
+    {
+        $width = 0;
+
+        for ($i = 0, $length = strlen($indentation); $i < $length; $i++) {
+            $width = match ($indentation[$i]) {
+                "\t" => intdiv($width, 8) * 8 + 8,
+                "\f" => 0,
+                default => $width + 1,
+            };
+        }
+
+        return $width;
+    }
+}
diff --git a/src/Languages/Python/Patterns/PyKeywordPattern.php b/src/Languages/Python/Patterns/PyKeywordPattern.php
index eb13e4cb..ce43cb61 100644
--- a/src/Languages/Python/Patterns/PyKeywordPattern.php
+++ b/src/Languages/Python/Patterns/PyKeywordPattern.php
@@ -25,7 +25,7 @@ public function getPattern(): string
     {
         $keywords = implode('|', $this->keywords);
 
-        return "\b(?<match>(?:_(?=\s*:){$keywords}))\b";
+        return "\b(?<match>(?:{$keywords}))\b";
     }
 
     public function getTokenType(): TokenTypeEnum
diff --git a/src/Languages/Python/Patterns/PyTripleDoubleQuoteStringPattern.php b/src/Languages/Python/Patterns/PyTripleDoubleQuoteStringPattern.php
index 7f249b7d..463a4004 100644
--- a/src/Languages/Python/Patterns/PyTripleDoubleQuoteStringPattern.php
+++ b/src/Languages/Python/Patterns/PyTripleDoubleQuoteStringPattern.php
@@ -14,7 +14,7 @@
 
     public function getPattern(): string
     {
-        return '/(?<match>"""(.|\n)*?""")/m';
+        return '/(?<match>"""[\s\S]*?""")/m';
     }
 
     public function getTokenType(): TokenTypeEnum
diff --git a/src/Languages/Python/Patterns/PyTripleSingleQuoteStringPattern.php b/src/Languages/Python/Patterns/PyTripleSingleQuoteStringPattern.php
index 7f120249..a46a582e 100644
--- a/src/Languages/Python/Patterns/PyTripleSingleQuoteStringPattern.php
+++ b/src/Languages/Python/Patterns/PyTripleSingleQuoteStringPattern.php
@@ -14,7 +14,7 @@
 
     public function getPattern(): string
     {
-        return '/(?<match>\'\'\'(.|\n)*?\'\'\')/m';
+        return '/(?<match>\'\'\'[\s\S]*?\'\'\')/m';
     }
 
     public function getTokenType(): TokenTypeEnum
diff --git a/src/Languages/Python/PythonLanguage.php b/src/Languages/Python/PythonLanguage.php
index e9dc4ae2..a2a4d18e 100644
--- a/src/Languages/Python/PythonLanguage.php
+++ b/src/Languages/Python/PythonLanguage.php
@@ -10,6 +10,7 @@
 use Tempest\Highlight\Languages\Php\Patterns\SingleQuoteValuePattern;
 use Tempest\Highlight\Languages\Python\Patterns\PyArgumentPattern;
 use Tempest\Highlight\Languages\Python\Patterns\PyBuiltinPattern;
+use Tempest\Highlight\Languages\Python\Patterns\PyCaseWildcardPattern;
 use Tempest\Highlight\Languages\Python\Patterns\PyClassNamePattern;
 use Tempest\Highlight\Languages\Python\Patterns\PyCommentPattern;
 use Tempest\Highlight\Languages\Python\Patterns\PyDecoratorPattern;
@@ -50,6 +51,7 @@ public function getPatterns(): array
 
             // KEYWORDS
             new PyKeywordPattern(),
+            new PyCaseWildcardPattern(),
 
             // PROPERTY
             new PyClassNamePattern(),
diff --git a/src/Languages/Ruby/Patterns/RubyCommentPattern.php b/src/Languages/Ruby/Patterns/RubyCommentPattern.php
index 32c2fc76..092b93ee 100644
--- a/src/Languages/Ruby/Patterns/RubyCommentPattern.php
+++ b/src/Languages/Ruby/Patterns/RubyCommentPattern.php
@@ -28,9 +28,14 @@
 )]
 final readonly class RubyCommentPattern implements Pattern
 {
+    public function __construct(
+        private RubyLexer $lexer = new RubyLexer(),
+    ) {
+    }
+
     public function match(string $content): array
     {
-        return ['match' => new RubyLexer()->lex($content)['comment']];
+        return ['match' => $this->lexer->lex($content)['comment']];
     }
 
     public function getTokenType(): TokenTypeEnum
diff --git a/src/Languages/Ruby/Patterns/RubyConstantPattern.php b/src/Languages/Ruby/Patterns/RubyConstantPattern.php
index f1ccee51..bb176727 100644
--- a/src/Languages/Ruby/Patterns/RubyConstantPattern.php
+++ b/src/Languages/Ruby/Patterns/RubyConstantPattern.php
@@ -19,9 +19,14 @@
         match as matchContent;
     }
 
+    public function __construct(
+        private RubyLexer $lexer = new RubyLexer(),
+    ) {
+    }
+
     public function match(string $content): array
     {
-        return $this->matchContent(new RubyLexer()->code($content));
+        return $this->matchContent($this->lexer->code($content));
     }
 
     public function getPattern(): string
diff --git a/src/Languages/Ruby/Patterns/RubyHashKeyPattern.php b/src/Languages/Ruby/Patterns/RubyHashKeyPattern.php
index 6cc65e44..450c501e 100644
--- a/src/Languages/Ruby/Patterns/RubyHashKeyPattern.php
+++ b/src/Languages/Ruby/Patterns/RubyHashKeyPattern.php
@@ -23,9 +23,14 @@
         match as matchContent;
     }
 
+    public function __construct(
+        private RubyLexer $lexer = new RubyLexer(),
+    ) {
+    }
+
     public function match(string $content): array
     {
-        return $this->matchContent(new RubyLexer()->code($content));
+        return $this->matchContent($this->lexer->code($content));
     }
 
     public function getPattern(): string
diff --git a/src/Languages/Ruby/Patterns/RubyHeredocPattern.php b/src/Languages/Ruby/Patterns/RubyHeredocPattern.php
index d399285e..99bbb0f3 100644
--- a/src/Languages/Ruby/Patterns/RubyHeredocPattern.php
+++ b/src/Languages/Ruby/Patterns/RubyHeredocPattern.php
@@ -26,9 +26,14 @@
 #[PatternTest(input: 'items << item', output: null)]
 final readonly class RubyHeredocPattern implements Pattern
 {
+    public function __construct(
+        private RubyLexer $lexer = new RubyLexer(),
+    ) {
+    }
+
     public function match(string $content): array
     {
-        return ['match' => new RubyLexer()->lex($content)['heredoc']];
+        return ['match' => $this->lexer->lex($content)['heredoc']];
     }
 
     public function getTokenType(): TokenTypeEnum
diff --git a/src/Languages/Ruby/Patterns/RubyKeywordPattern.php b/src/Languages/Ruby/Patterns/RubyKeywordPattern.php
index 7f240ee2..aa926c03 100644
--- a/src/Languages/Ruby/Patterns/RubyKeywordPattern.php
+++ b/src/Languages/Ruby/Patterns/RubyKeywordPattern.php
@@ -23,7 +23,7 @@
 
     public function match(string $content): array
     {
-        return $this->matchContent(new RubyLexer()->code($content));
+        return $this->matchContent($this->lexer->code($content));
     }
 
     public function __construct(private array $keywords = [
@@ -35,7 +35,7 @@ public function __construct(private array $keywords = [
         'attr_accessor', 'attr_reader', 'attr_writer', 'extend', 'include',
         'module_function', 'prepend', 'private', 'private_constant', 'protected',
         'public', 'raise', 'require', 'require_relative',
-    ])
+    ], private RubyLexer $lexer = new RubyLexer())
     {
     }
 
diff --git a/src/Languages/Ruby/Patterns/RubyLiteralPattern.php b/src/Languages/Ruby/Patterns/RubyLiteralPattern.php
index d50012ed..56f4c803 100644
--- a/src/Languages/Ruby/Patterns/RubyLiteralPattern.php
+++ b/src/Languages/Ruby/Patterns/RubyLiteralPattern.php
@@ -19,9 +19,14 @@
         match as matchContent;
     }
 
+    public function __construct(
+        private RubyLexer $lexer = new RubyLexer(),
+    ) {
+    }
+
     public function match(string $content): array
     {
-        return $this->matchContent(new RubyLexer()->code($content));
+        return $this->matchContent($this->lexer->code($content));
     }
 
     public function getPattern(): string
diff --git a/src/Languages/Ruby/Patterns/RubyMethodNamePattern.php b/src/Languages/Ruby/Patterns/RubyMethodNamePattern.php
index 1a5ff0ba..641d04c0 100644
--- a/src/Languages/Ruby/Patterns/RubyMethodNamePattern.php
+++ b/src/Languages/Ruby/Patterns/RubyMethodNamePattern.php
@@ -22,9 +22,14 @@
         match as matchContent;
     }
 
+    public function __construct(
+        private RubyLexer $lexer = new RubyLexer(),
+    ) {
+    }
+
     public function match(string $content): array
     {
-        return $this->matchContent(new RubyLexer()->code($content));
+        return $this->matchContent($this->lexer->code($content));
     }
 
     public function getPattern(): string
diff --git a/src/Languages/Ruby/Patterns/RubyNumberPattern.php b/src/Languages/Ruby/Patterns/RubyNumberPattern.php
index ab3e2fac..b773c424 100644
--- a/src/Languages/Ruby/Patterns/RubyNumberPattern.php
+++ b/src/Languages/Ruby/Patterns/RubyNumberPattern.php
@@ -22,9 +22,14 @@
         match as matchContent;
     }
 
+    public function __construct(
+        private RubyLexer $lexer = new RubyLexer(),
+    ) {
+    }
+
     public function match(string $content): array
     {
-        return $this->matchContent(new RubyLexer()->code($content));
+        return $this->matchContent($this->lexer->code($content));
     }
 
     public function getPattern(): string
diff --git a/src/Languages/Ruby/Patterns/RubyOperatorPattern.php b/src/Languages/Ruby/Patterns/RubyOperatorPattern.php
index 7b4c1faa..eb467868 100644
--- a/src/Languages/Ruby/Patterns/RubyOperatorPattern.php
+++ b/src/Languages/Ruby/Patterns/RubyOperatorPattern.php
@@ -22,9 +22,14 @@
         match as matchContent;
     }
 
+    public function __construct(
+        private RubyLexer $lexer = new RubyLexer(),
+    ) {
+    }
+
     public function match(string $content): array
     {
-        return $this->matchContent(new RubyLexer()->code($content));
+        return $this->matchContent($this->lexer->code($content));
     }
 
     public function getPattern(): string
diff --git a/src/Languages/Ruby/Patterns/RubyPercentLiteralPattern.php b/src/Languages/Ruby/Patterns/RubyPercentLiteralPattern.php
index 7cf46573..a038c3f2 100644
--- a/src/Languages/Ruby/Patterns/RubyPercentLiteralPattern.php
+++ b/src/Languages/Ruby/Patterns/RubyPercentLiteralPattern.php
@@ -17,9 +17,14 @@
 #[PatternTest(input: 'x = 10 %q[0]', output: null)]
 final readonly class RubyPercentLiteralPattern implements Pattern
 {
+    public function __construct(
+        private RubyLexer $lexer = new RubyLexer(),
+    ) {
+    }
+
     public function match(string $content): array
     {
-        return ['match' => new RubyLexer()->lex($content)['percent']];
+        return ['match' => $this->lexer->lex($content)['percent']];
     }
 
     public function getTokenType(): TokenTypeEnum
diff --git a/src/Languages/Ruby/Patterns/RubyRegexPattern.php b/src/Languages/Ruby/Patterns/RubyRegexPattern.php
index 9e76ddb1..a4f6c89c 100644
--- a/src/Languages/Ruby/Patterns/RubyRegexPattern.php
+++ b/src/Languages/Ruby/Patterns/RubyRegexPattern.php
@@ -15,9 +15,14 @@
 #[PatternTest(input: 'ratio = total/count', output: null)]
 final readonly class RubyRegexPattern implements Pattern
 {
+    public function __construct(
+        private RubyLexer $lexer = new RubyLexer(),
+    ) {
+    }
+
     public function match(string $content): array
     {
-        return ['match' => new RubyLexer()->lex($content)['regex']];
+        return ['match' => $this->lexer->lex($content)['regex']];
     }
 
     public function getTokenType(): TokenTypeEnum
diff --git a/src/Languages/Ruby/Patterns/RubyStringPattern.php b/src/Languages/Ruby/Patterns/RubyStringPattern.php
index 05715714..f55063df 100644
--- a/src/Languages/Ruby/Patterns/RubyStringPattern.php
+++ b/src/Languages/Ruby/Patterns/RubyStringPattern.php
@@ -21,9 +21,14 @@
 #[PatternTest(input: "words = %w[it's]", output: null)]
 final readonly class RubyStringPattern implements Pattern
 {
+    public function __construct(
+        private RubyLexer $lexer = new RubyLexer(),
+    ) {
+    }
+
     public function match(string $content): array
     {
-        return ['match' => new RubyLexer()->lex($content)['string']];
+        return ['match' => $this->lexer->lex($content)['string']];
     }
 
     public function getTokenType(): TokenTypeEnum
diff --git a/src/Languages/Ruby/Patterns/RubySymbolPattern.php b/src/Languages/Ruby/Patterns/RubySymbolPattern.php
index d010635a..2750cbb4 100644
--- a/src/Languages/Ruby/Patterns/RubySymbolPattern.php
+++ b/src/Languages/Ruby/Patterns/RubySymbolPattern.php
@@ -24,12 +24,17 @@
         match as matchBareSymbols;
     }
 
+    public function __construct(
+        private RubyLexer $lexer = new RubyLexer(),
+    ) {
+    }
+
     public function match(string $content): array
     {
         return [
             'match' => [
-                ...$this->matchBareSymbols(new RubyLexer()->code($content))['match'] ?? [],
-                ...new RubyLexer()->lex($content)['symbol'],
+                ...$this->matchBareSymbols($this->lexer->code($content))['match'] ?? [],
+                ...$this->lexer->lex($content)['symbol'],
             ],
         ];
     }
diff --git a/src/Languages/Ruby/Patterns/RubyVariablePattern.php b/src/Languages/Ruby/Patterns/RubyVariablePattern.php
index 4aac5b18..4f8550a4 100644
--- a/src/Languages/Ruby/Patterns/RubyVariablePattern.php
+++ b/src/Languages/Ruby/Patterns/RubyVariablePattern.php
@@ -20,9 +20,14 @@
         match as matchContent;
     }
 
+    public function __construct(
+        private RubyLexer $lexer = new RubyLexer(),
+    ) {
+    }
+
     public function match(string $content): array
     {
-        return $this->matchContent(new RubyLexer()->code($content));
+        return $this->matchContent($this->lexer->code($content));
     }
 
     public function getPattern(): string
diff --git a/src/Languages/Ruby/RubyLanguage.php b/src/Languages/Ruby/RubyLanguage.php
index ad100e46..2b97641b 100644
--- a/src/Languages/Ruby/RubyLanguage.php
+++ b/src/Languages/Ruby/RubyLanguage.php
@@ -37,40 +37,42 @@ public function getAliases(): array
     #[Override]
     public function getPatterns(): array
     {
+        $lexer = new RubyLexer();
+
         return [
             ...parent::getPatterns(),
 
             // COMMENTS
-            new RubyCommentPattern(),
+            new RubyCommentPattern(lexer: $lexer),
 
             // VALUES
-            new RubyHeredocPattern(),
-            new RubyPercentLiteralPattern(),
-            new RubyStringPattern(),
-            new RubyRegexPattern(),
+            new RubyHeredocPattern(lexer: $lexer),
+            new RubyPercentLiteralPattern(lexer: $lexer),
+            new RubyStringPattern(lexer: $lexer),
+            new RubyRegexPattern(lexer: $lexer),
 
             // PROPERTIES
-            new RubyMethodNamePattern(),
-            new RubyHashKeyPattern(),
+            new RubyMethodNamePattern(lexer: $lexer),
+            new RubyHashKeyPattern(lexer: $lexer),
 
             // KEYWORDS
-            new RubyKeywordPattern(),
+            new RubyKeywordPattern(lexer: $lexer),
 
             // TYPES
-            new RubyConstantPattern(),
+            new RubyConstantPattern(lexer: $lexer),
 
             // LITERALS
-            new RubyLiteralPattern(),
-            new RubySymbolPattern(),
+            new RubyLiteralPattern(lexer: $lexer),
+            new RubySymbolPattern(lexer: $lexer),
 
             // VARIABLES
-            new RubyVariablePattern(),
+            new RubyVariablePattern(lexer: $lexer),
 
             // NUMBERS
-            new RubyNumberPattern(),
+            new RubyNumberPattern(lexer: $lexer),
 
             // OPERATORS
-            new RubyOperatorPattern(),
+            new RubyOperatorPattern(lexer: $lexer),
         ];
     }
 }
diff --git a/src/Languages/Ruby/RubyLexer.php b/src/Languages/Ruby/RubyLexer.php
index be5e530d..15937237 100644
--- a/src/Languages/Ruby/RubyLexer.php
+++ b/src/Languages/Ruby/RubyLexer.php
@@ -44,32 +44,32 @@ final class RubyLexer
     /** @var array<int, ?int> */
     private array $interpolationEnds = [];
 
-    private static ?string $lastContent = null;
+    private ?string $lastContent = null;
 
-    private static array $lastLiterals = [];
+    private array $lastLiterals = [];
 
-    private static ?string $lastCode = null;
+    private ?string $lastCode = null;
 
     /**
      * @return array{comment: list<array{string, int}>, heredoc: list<array{string, int}>, percent: list<array{string, int}>, regex: list<array{string, int}>, string: list<array{string, int}>, symbol: list<array{string, int}>}
      */
     public function lex(string $content): array
     {
-        if ($content !== self::$lastContent) {
-            self::$lastLiterals = $this->scan($content);
-            self::$lastContent = $content;
-            self::$lastCode = null;
+        if ($content !== $this->lastContent) {
+            $this->lastLiterals = $this->scan($content);
+            $this->lastContent = $content;
+            $this->lastCode = null;
         }
 
-        return self::$lastLiterals;
+        return $this->lastLiterals;
     }
 
     public function code(string $content): string
     {
         $literals = $this->lex($content);
 
-        if (self::$lastCode !== null) {
-            return self::$lastCode;
+        if ($this->lastCode !== null) {
+            return $this->lastCode;
         }
 
         $regions = array_merge(...array_values($literals));
@@ -87,7 +87,7 @@ public function code(string $content): string
 
         $parts[] = substr($content, $cursor);
 
-        return self::$lastCode = implode('', $parts);
+        return $this->lastCode = implode('', $parts);
     }
 
     private function scan(string $content): array
diff --git a/src/Languages/Sql/Patterns/SqlMultilineCommentPattern.php b/src/Languages/Sql/Patterns/SqlMultilineCommentPattern.php
index 22b25bc7..83a2df82 100644
--- a/src/Languages/Sql/Patterns/SqlMultilineCommentPattern.php
+++ b/src/Languages/Sql/Patterns/SqlMultilineCommentPattern.php
@@ -23,7 +23,8 @@
 
     public function getPattern(): string
     {
-        return '/(?<match>\/\*(.|\n)*?\*\/)/m';
+        // (*COMMIT) stops the search when an opener has no closer: later openers cannot have one either.
+        return '/(?<match>\/\*(?:[\s\S]*?\*\/|(*COMMIT)(*FAIL)))/m';
     }
 
     public function getTokenType(): TokenTypeEnum
diff --git a/src/Languages/Sql/Patterns/SqlSinglelineCommentPattern.php b/src/Languages/Sql/Patterns/SqlSinglelineCommentPattern.php
index 61a45869..c9b07d34 100644
--- a/src/Languages/Sql/Patterns/SqlSinglelineCommentPattern.php
+++ b/src/Languages/Sql/Patterns/SqlSinglelineCommentPattern.php
@@ -16,7 +16,7 @@
 
     public function getPattern(): string
     {
-        return '(?<match>\-\-(.)*)';
+        return '(?<match>\-\-.*)';
     }
 
     public function getTokenType(): TokenTypeEnum
diff --git a/src/Languages/Svelte/Injections/SvelteBlockExpressionInjection.php b/src/Languages/Svelte/Injections/SvelteBlockExpressionInjection.php
index 77ab5163..050b5eca 100644
--- a/src/Languages/Svelte/Injections/SvelteBlockExpressionInjection.php
+++ b/src/Languages/Svelte/Injections/SvelteBlockExpressionInjection.php
@@ -7,7 +7,9 @@
 use Tempest\Highlight\Highlighter;
 use Tempest\Highlight\Injection;
 use Tempest\Highlight\IsInjection;
+use Tempest\Highlight\RequiresSubstring;
 
+#[RequiresSubstring('{#', '{@', '{:', '{/')]
 final class SvelteBlockExpressionInjection implements Injection
 {
     use IsInjection;
diff --git a/src/Languages/Svelte/Injections/SvelteExpressionInjection.php b/src/Languages/Svelte/Injections/SvelteExpressionInjection.php
index be60d58a..f100229c 100644
--- a/src/Languages/Svelte/Injections/SvelteExpressionInjection.php
+++ b/src/Languages/Svelte/Injections/SvelteExpressionInjection.php
@@ -8,11 +8,13 @@
 use Tempest\Highlight\Injection;
 use Tempest\Highlight\IsInjection;
 use Tempest\Highlight\PatternTest;
+use Tempest\Highlight\RequiresSubstring;
 
 #[PatternTest(input: '{role}', output: 'role')]
 #[PatternTest(input: '{role.id}', output: 'role.id')]
 #[PatternTest(input: 'onclick={() => count++}', output: '() => count++')]
 #[PatternTest(input: 'onclick={() => { updateTab() }}', output: '() => { updateTab() }')]
+#[RequiresSubstring('{')]
 final class SvelteExpressionInjection implements Injection
 {
     use IsInjection;
diff --git a/src/Languages/Svelte/Injections/SvelteTypeScriptInjection.php b/src/Languages/Svelte/Injections/SvelteTypeScriptInjection.php
index c62ecf86..012edb77 100644
--- a/src/Languages/Svelte/Injections/SvelteTypeScriptInjection.php
+++ b/src/Languages/Svelte/Injections/SvelteTypeScriptInjection.php
@@ -7,7 +7,9 @@
 use Tempest\Highlight\Highlighter;
 use Tempest\Highlight\Injection;
 use Tempest\Highlight\IsInjection;
+use Tempest\Highlight\RequiresSubstring;
 
+#[RequiresSubstring('lang="ts">')]
 final class SvelteTypeScriptInjection implements Injection
 {
     use IsInjection;
diff --git a/src/Languages/Twig/Injections/TwigEchoInjection.php b/src/Languages/Twig/Injections/TwigEchoInjection.php
index 480cf227..edf6fea7 100644
--- a/src/Languages/Twig/Injections/TwigEchoInjection.php
+++ b/src/Languages/Twig/Injections/TwigEchoInjection.php
@@ -9,18 +9,24 @@
 use Tempest\Highlight\Injection;
 use Tempest\Highlight\IsInjection;
 use Tempest\Highlight\Languages\Twig\TwigEchoLanguage;
+use Tempest\Highlight\RequiresSubstring;
 
+#[RequiresSubstring('{{')]
 class TwigEchoInjection implements Injection
 {
     use IsInjection;
 
     public function getPattern(): string
     {
-        return '(?<match>({{(.|\n)*?}}))';
+        // (*COMMIT) stops the search when an opener has no closer: later openers cannot have one either.
+        return '(?<match>({{(*COMMIT)[\s\S]*?}}))';
     }
 
     public function parseContent(string $content, Highlighter $highlighter): string
     {
-        return Escape::injection($highlighter->parse($content, new TwigEchoLanguage()));
+        // One shared instance, so the highlighter's per-language caches hit on every match
+        static $language = new TwigEchoLanguage();
+
+        return Escape::injection($highlighter->parse($content, $language));
     }
 }
diff --git a/src/Languages/Twig/Injections/TwigTagInjection.php b/src/Languages/Twig/Injections/TwigTagInjection.php
index 5a73bb3a..5b1c9631 100644
--- a/src/Languages/Twig/Injections/TwigTagInjection.php
+++ b/src/Languages/Twig/Injections/TwigTagInjection.php
@@ -9,18 +9,24 @@
 use Tempest\Highlight\Injection;
 use Tempest\Highlight\IsInjection;
 use Tempest\Highlight\Languages\Twig\TwigTagLanguage;
+use Tempest\Highlight\RequiresSubstring;
 
+#[RequiresSubstring('{%')]
 class TwigTagInjection implements Injection
 {
     use IsInjection;
 
     public function getPattern(): string
     {
-        return '(?<match>({%(.|\n)*?%}))';
+        // (*COMMIT) stops the search when an opener has no closer: later openers cannot have one either.
+        return '(?<match>({%(*COMMIT)[\s\S]*?%}))';
     }
 
     public function parseContent(string $content, Highlighter $highlighter): string
     {
-        return Escape::injection($highlighter->parse($content, new TwigTagLanguage()));
+        // One shared instance, so the highlighter's per-language caches hit on every match
+        static $language = new TwigTagLanguage();
+
+        return Escape::injection($highlighter->parse($content, $language));
     }
 }
diff --git a/src/Languages/Twig/Patterns/CombinedTwigKeywordPattern.php b/src/Languages/Twig/Patterns/CombinedTwigKeywordPattern.php
new file mode 100644
index 00000000..c6097602
--- /dev/null
+++ b/src/Languages/Twig/Patterns/CombinedTwigKeywordPattern.php
@@ -0,0 +1,50 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tempest\Highlight\Languages\Twig\Patterns;
+
+use InvalidArgumentException;
+use Tempest\Highlight\Pattern;
+use Tempest\Highlight\Tokens\TokenTypeEnum;
+
+final readonly class CombinedTwigKeywordPattern implements Pattern
+{
+    private string $compiledPattern;
+
+    /**
+     * @param string[] $keywords
+     */
+    public function __construct(array $keywords)
+    {
+        $keywords = array_values(array_unique($keywords));
+
+        if ($keywords === []) {
+            throw new InvalidArgumentException('At least one keyword is required.');
+        }
+
+        usort($keywords, static fn (string $a, string $b): int => strlen($b) <=> strlen($a));
+
+        $alternation = implode(
+            '|',
+            array_map(
+                static fn (string $keyword): string => preg_quote($keyword, '/'),
+                $keywords,
+            ),
+        );
+
+        $this->compiledPattern = "/\b(?<match>(?:{$alternation}))\b/";
+    }
+
+    public function match(string $content): array
+    {
+        preg_match_all($this->compiledPattern, $content, $matches, PREG_OFFSET_CAPTURE);
+
+        return $matches;
+    }
+
+    public function getTokenType(): TokenTypeEnum
+    {
+        return TokenTypeEnum::KEYWORD;
+    }
+}
diff --git a/src/Languages/Twig/Patterns/TwigCommentPattern.php b/src/Languages/Twig/Patterns/TwigCommentPattern.php
index 02af7781..aff03cc8 100644
--- a/src/Languages/Twig/Patterns/TwigCommentPattern.php
+++ b/src/Languages/Twig/Patterns/TwigCommentPattern.php
@@ -24,7 +24,8 @@
 
     public function getPattern(): string
     {
-        return '(?<match>\{#(.|\n)*?#})';
+        // (*COMMIT) stops the search when an opener has no closer: later openers cannot have one either.
+        return '(?<match>\{#(?:[\s\S]*?#}|(*COMMIT)(*FAIL)))';
     }
 
     public function getTokenType(): TokenTypeEnum
diff --git a/src/Languages/Twig/Patterns/TwigKeywordPattern.php b/src/Languages/Twig/Patterns/TwigKeywordPattern.php
index 2f351c71..bf0712be 100644
--- a/src/Languages/Twig/Patterns/TwigKeywordPattern.php
+++ b/src/Languages/Twig/Patterns/TwigKeywordPattern.php
@@ -12,7 +12,7 @@ final class TwigKeywordPattern implements Pattern
 {
     use IsPattern;
 
-    public function __construct(private string $keyword)
+    public function __construct(private readonly string $keyword)
     {
     }
 
diff --git a/src/Languages/Twig/TwigTagLanguage.php b/src/Languages/Twig/TwigTagLanguage.php
index 3d8c1f6d..4389db9d 100644
--- a/src/Languages/Twig/TwigTagLanguage.php
+++ b/src/Languages/Twig/TwigTagLanguage.php
@@ -6,10 +6,10 @@
 
 use Override;
 use Tempest\Highlight\Languages\Base\BaseLanguage;
+use Tempest\Highlight\Languages\Twig\Patterns\CombinedTwigKeywordPattern;
 use Tempest\Highlight\Languages\Twig\Patterns\TwigArrayKeyPattern;
 use Tempest\Highlight\Languages\Twig\Patterns\TwigDoubleQuoteValuePattern;
 use Tempest\Highlight\Languages\Twig\Patterns\TwigFilterPattern;
-use Tempest\Highlight\Languages\Twig\Patterns\TwigKeywordPattern;
 use Tempest\Highlight\Languages\Twig\Patterns\TwigMethodPattern;
 use Tempest\Highlight\Languages\Twig\Patterns\TwigNamedArgumentPattern;
 use Tempest\Highlight\Languages\Twig\Patterns\TwigPropertyPattern;
@@ -40,44 +40,45 @@ public function getPatterns(): array
             new TwigSingleQuoteValuePattern(),
 
             // KEYWORDS
-            new TwigKeywordPattern('set'),
-            new TwigKeywordPattern('apply'),
-            new TwigKeywordPattern('autoescape'),
-            new TwigKeywordPattern('endautoescape'),
-            new TwigKeywordPattern('block'),
-            new TwigKeywordPattern('endblock'),
-            new TwigKeywordPattern('cache'),
-            new TwigKeywordPattern('deprecated'),
-            new TwigKeywordPattern('do'),
-            new TwigKeywordPattern('embed'),
-            new TwigKeywordPattern('extends'),
-            new TwigKeywordPattern('flush'),
-            new TwigKeywordPattern('for'),
-            new TwigKeywordPattern('endfor'),
-            new TwigKeywordPattern('from'),
-            new TwigKeywordPattern('if'),
-            new TwigKeywordPattern('else'),
-            new TwigKeywordPattern('elseif'),
-            new TwigKeywordPattern('endif'),
-            new TwigKeywordPattern('import'),
-            new TwigKeywordPattern('include'),
-            new TwigKeywordPattern('macro'),
-            new TwigKeywordPattern('endmacro'),
-            new TwigKeywordPattern('sandbox'),
-            new TwigKeywordPattern('set'),
-            new TwigKeywordPattern('use'),
-            new TwigKeywordPattern('verbatim'),
-            new TwigKeywordPattern('with'),
-            new TwigKeywordPattern('end'),
-            new TwigKeywordPattern('as'),
-            new TwigKeywordPattern('in'),
-            new TwigKeywordPattern('endapply'),
-            new TwigKeywordPattern('endcache'),
-            new TwigKeywordPattern('endembed'),
-            new TwigKeywordPattern('endset'),
-            new TwigKeywordPattern('endsandbox'),
-            new TwigKeywordPattern('endverbatim'),
-            new TwigKeywordPattern('endwith'),
+            new CombinedTwigKeywordPattern([
+                'set',
+                'apply',
+                'autoescape',
+                'endautoescape',
+                'block',
+                'endblock',
+                'cache',
+                'deprecated',
+                'do',
+                'embed',
+                'extends',
+                'flush',
+                'for',
+                'endfor',
+                'from',
+                'if',
+                'else',
+                'elseif',
+                'endif',
+                'import',
+                'include',
+                'macro',
+                'endmacro',
+                'sandbox',
+                'use',
+                'verbatim',
+                'with',
+                'end',
+                'as',
+                'in',
+                'endapply',
+                'endcache',
+                'endembed',
+                'endset',
+                'endsandbox',
+                'endverbatim',
+                'endwith',
+            ]),
         ];
     }
 }
diff --git a/src/Languages/Vue/Injections/VueInterpolationInjection.php b/src/Languages/Vue/Injections/VueInterpolationInjection.php
index 72cf9838..f555706a 100644
--- a/src/Languages/Vue/Injections/VueInterpolationInjection.php
+++ b/src/Languages/Vue/Injections/VueInterpolationInjection.php
@@ -8,10 +8,12 @@
 use Tempest\Highlight\Injection;
 use Tempest\Highlight\IsInjection;
 use Tempest\Highlight\PatternTest;
+use Tempest\Highlight\RequiresSubstring;
 
 #[PatternTest(input: '{{ name }}', output: ' name ')]
 #[PatternTest(input: '{{ user.id }}', output: ' user.id ')]
 #[PatternTest(input: '{{ count + 1 }}', output: ' count + 1 ')]
+#[RequiresSubstring('{{')]
 final class VueInterpolationInjection implements Injection
 {
     use IsInjection;
diff --git a/src/Languages/Vue/Injections/VueScriptSetupInjection.php b/src/Languages/Vue/Injections/VueScriptSetupInjection.php
index adec40dc..16d03c43 100644
--- a/src/Languages/Vue/Injections/VueScriptSetupInjection.php
+++ b/src/Languages/Vue/Injections/VueScriptSetupInjection.php
@@ -7,7 +7,9 @@
 use Tempest\Highlight\Highlighter;
 use Tempest\Highlight\Injection;
 use Tempest\Highlight\IsInjection;
+use Tempest\Highlight\RequiresSubstring;
 
+#[RequiresSubstring('</script>')]
 final class VueScriptSetupInjection implements Injection
 {
     use IsInjection;
diff --git a/src/Languages/Vue/Injections/VueStyleScopedInjection.php b/src/Languages/Vue/Injections/VueStyleScopedInjection.php
index e80abd65..07a0613b 100644
--- a/src/Languages/Vue/Injections/VueStyleScopedInjection.php
+++ b/src/Languages/Vue/Injections/VueStyleScopedInjection.php
@@ -7,7 +7,9 @@
 use Tempest\Highlight\Highlighter;
 use Tempest\Highlight\Injection;
 use Tempest\Highlight\IsInjection;
+use Tempest\Highlight\RequiresSubstring;
 
+#[RequiresSubstring('</style>')]
 final class VueStyleScopedInjection implements Injection
 {
     use IsInjection;
diff --git a/src/Languages/Vue/Injections/VueStyleScssInjection.php b/src/Languages/Vue/Injections/VueStyleScssInjection.php
index b333ba3a..1182dac2 100644
--- a/src/Languages/Vue/Injections/VueStyleScssInjection.php
+++ b/src/Languages/Vue/Injections/VueStyleScssInjection.php
@@ -7,7 +7,9 @@
 use Tempest\Highlight\Highlighter;
 use Tempest\Highlight\Injection;
 use Tempest\Highlight\IsInjection;
+use Tempest\Highlight\RequiresSubstring;
 
+#[RequiresSubstring('lang="s')]
 final class VueStyleScssInjection implements Injection
 {
     use IsInjection;
diff --git a/src/Languages/Vue/Injections/VueTypeScriptInjection.php b/src/Languages/Vue/Injections/VueTypeScriptInjection.php
index a9e45c17..77f67661 100644
--- a/src/Languages/Vue/Injections/VueTypeScriptInjection.php
+++ b/src/Languages/Vue/Injections/VueTypeScriptInjection.php
@@ -7,7 +7,9 @@
 use Tempest\Highlight\Highlighter;
 use Tempest\Highlight\Injection;
 use Tempest\Highlight\IsInjection;
+use Tempest\Highlight\RequiresSubstring;
 
+#[RequiresSubstring('lang="ts"')]
 final class VueTypeScriptInjection implements Injection
 {
     use IsInjection;
diff --git a/src/Languages/Xml/Patterns/XmlCommentPattern.php b/src/Languages/Xml/Patterns/XmlCommentPattern.php
index 13ff8451..f17bcd26 100644
--- a/src/Languages/Xml/Patterns/XmlCommentPattern.php
+++ b/src/Languages/Xml/Patterns/XmlCommentPattern.php
@@ -26,7 +26,8 @@
 
     public function getPattern(): string
     {
-        return '/(?<match>\<!--(.|\n)*-->)/mU';
+        // (*COMMIT) stops the search when an opener has no closer: later openers cannot have one either.
+        return '/(?<match>\<!--(?:[\s\S]*-->|(*COMMIT)(*FAIL)))/mU';
     }
 
     public function getTokenType(): TokenTypeEnum
diff --git a/src/Languages/Yaml/Patterns/YamlCommentPattern.php b/src/Languages/Yaml/Patterns/YamlCommentPattern.php
index 0f5ab4d6..f3f9d81b 100644
--- a/src/Languages/Yaml/Patterns/YamlCommentPattern.php
+++ b/src/Languages/Yaml/Patterns/YamlCommentPattern.php
@@ -16,7 +16,7 @@
 
     public function getPattern(): string
     {
-        return '(?<match>\#(.)*)';
+        return '(?<match>\#.*)';
     }
 
     public function getTokenType(): TokenTypeEnum
diff --git a/src/RequiresSubstring.php b/src/RequiresSubstring.php
new file mode 100644
index 00000000..18ac2371
--- /dev/null
+++ b/src/RequiresSubstring.php
@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tempest\Highlight;
+
+use Attribute;
+
+/**
+ * Marks a pattern or injection that can only have an effect when the content
+ * contains at least one of the given substrings, so the highlighter may skip it.
+ * Without substrings it imposes no requirement.
+ */
+#[Attribute(Attribute::TARGET_CLASS)]
+final readonly class RequiresSubstring
+{
+    /** @var string[] */
+    public array $substrings;
+
+    public function __construct(string ...$substrings)
+    {
+        $this->substrings = $substrings;
+    }
+}
diff --git a/src/Themes/InlineTheme.php b/src/Themes/InlineTheme.php
index 437ca94f..7b91be9d 100644
--- a/src/Themes/InlineTheme.php
+++ b/src/Themes/InlineTheme.php
@@ -26,7 +26,7 @@ public function __construct(string $themePath)
             throw new Exception("No valid CSS file found at path {$themePath}");
         }
 
-        preg_match_all('/(?<selector>[\w,\.\s\-]+){(?<style>(.|\n)*?)}/', $contents, $matches);
+        preg_match_all('/(?<selector>[\w,\.\s\-]+){(?<style>[\s\S]*?)}/', $contents, $matches);
 
         foreach (array_keys($matches[0]) as $key) {
             $selector = trim($matches['selector'][$key]);
diff --git a/src/Tokens/GroupTokens.php b/src/Tokens/GroupTokens.php
index 970c8077..2fb9bc0e 100644
--- a/src/Tokens/GroupTokens.php
+++ b/src/Tokens/GroupTokens.php
@@ -19,7 +19,7 @@ public function __invoke(array $tokens): array
         }
 
         // Sort tokens in the right order
-        $this->sortTokens($tokens);
+        $tokens = $this->sortTokens($tokens);
 
         // Group tokens by parent and child
         /** @var Token[] $groupedTokens */
@@ -32,7 +32,8 @@ public function __invoke(array $tokens): array
             }
 
             $token = $tokens[$i];
-            $token->resetHierarchy();
+            $token->children = [];
+            $token->parent = null;
             $tokenEnd = $token->end;
 
             // Since tokens are sorted by start, only check subsequent tokens
@@ -72,10 +73,56 @@ public function __invoke(array $tokens): array
      * Sort tokens by start position ascending, then by end position descending,
      * so that longer/parent tokens come before shorter/child tokens at the same start.
      *
+     * Ties keep their original order.
+     *
      * @param Token[] $tokens
+     * @return Token[]
      */
-    private function sortTokens(array &$tokens): void
+    private function sortTokens(array $tokens): array
     {
+        $low = PHP_INT_MAX;
+        $high = PHP_INT_MIN;
+
+        foreach ($tokens as $token) {
+            if ($token->start < $low) {
+                $low = $token->start;
+            }
+
+            if ($token->end < $low) {
+                $low = $token->end;
+            }
+
+            if ($token->start > $high) {
+                $high = $token->start;
+            }
+
+            if ($token->end > $high) {
+                $high = $token->end;
+            }
+        }
+
+        $range = $high - $low + 1;
+
+        // One packed key per token uses far less memory than array_multisort over four arrays.
+        // Both key parts lie in [0, $range), so a key is unique per (start, end) and below $range ** 2.
+        if ($range <= (int) sqrt(PHP_INT_MAX) && array_is_list($tokens)) {
+            $keys = [];
+
+            foreach ($tokens as $token) {
+                $keys[] = ($token->start - $low) * $range + ($high - $token->end);
+            }
+
+            asort($keys);
+
+            $sorted = [];
+
+            foreach ($keys as $index => $key) {
+                $sorted[] = $tokens[$index];
+            }
+
+            return $sorted;
+        }
+
         $starts = [];
         $negatedEnds = [];
         $indices = [];
@@ -98,5 +145,7 @@ private function sortTokens(array &$tokens): void
             SORT_NUMERIC,
             $tokens,
         );
+
+        return $tokens;
     }
 }
diff --git a/src/Tokens/ParseTokens.php b/src/Tokens/ParseTokens.php
index 6f3e0415..ee0fb80e 100644
--- a/src/Tokens/ParseTokens.php
+++ b/src/Tokens/ParseTokens.php
@@ -4,8 +4,11 @@
 
 namespace Tempest\Highlight\Tokens;
 
+use ReflectionClass;
+use Tempest\Highlight\IsPattern;
 use Tempest\Highlight\Language;
 use Tempest\Highlight\Languages\Php\Patterns\GenericPattern;
+use Tempest\Highlight\Pattern;
 
 final readonly class ParseTokens
 {
@@ -23,10 +26,21 @@ public function __invoke(string $content, Language $language): array
      */
     public function parse(string $content, array $patterns): array
     {
-        $tokens = [];
-        $seen = [];
+        return $this->parseCompiled($content, $this->compile($patterns));
+    }
+
+    /**
+     * Patterns from this package that use IsPattern::match() and only hold readonly state get their final regex and token type resolved once.
+     * Every other pattern keeps calling its own match() and getTokenType() on each parse.
+     *
+     * @internal
+     * @param array<int|string, mixed> $patterns
+     * @return array<int|string, array{?string, Pattern, ?TokenType, ?string}>
+     */
+    public function compile(array $patterns): array
+    {
+        $compiled = [];
 
-        // Match tokens from patterns
         foreach ($patterns as $key => $pattern) {
             if ($pattern instanceof TokenTypeEnum) {
                 $pattern = new GenericPattern(
@@ -35,7 +49,43 @@ public function parse(string $content, array $patterns): array
                 );
             }
 
-            $matches = $pattern->match($content);
+            if (! $this->usesBuiltInMatch($pattern)) {
+                $compiled[$key] = [null, $pattern, null, null];
+
+                continue;
+            }
+
+            $regex = $pattern->getPattern();
+
+            if (($regex[0] ?? '') !== '/') {
+                $regex = "/{$regex}/";
+            }
+
+            $tokenType = $pattern->getTokenType();
+
+            $compiled[$key] = [$regex, $pattern, $tokenType, $tokenType->getValue()];
+        }
+
+        return $compiled;
+    }
+
+    /**
+     * @internal
+     * @param array<int|string, array{?string, Pattern, ?TokenType, ?string}> $compiled
+     * @return Token[]
+     */
+    public function parseCompiled(string $content, array $compiled): array
+    {
+        $tokens = [];
+        $seen = [];
+
+        // Match tokens from patterns
+        foreach ($compiled as [$regex, $pattern, $tokenType, $tokenTypeValue]) {
+            if ($regex !== null) {
+                preg_match_all($regex, $content, $matches, PREG_OFFSET_CAPTURE);
+            } else {
+                $matches = $pattern->match($content);
+            }
 
             $match = $matches['match'] ?? null;
 
@@ -43,8 +93,15 @@ public function parse(string $content, array $patterns): array
                 continue;
             }
 
-            $tokenType = $pattern->getTokenType();
-            $tokenTypeValue = $tokenType->getValue();
+            // Built-in patterns have pure token types, so cloning one prototype equals constructing each token
+            $prototype = null;
+
+            if ($tokenType === null) {
+                $tokenType = $pattern->getTokenType();
+                $tokenTypeValue = $tokenType->getValue();
+            } else {
+                $prototype = new Token(0, '', $tokenType, $pattern, 0);
+            }
 
             foreach ($match as $item) {
                 $offset = $item[1];
@@ -58,16 +115,55 @@ public function parse(string $content, array $patterns): array
 
                 $seen[$hashKey] = true;
 
-                $tokens[] = new Token(
-                    offset: $offset,
-                    value: $value,
-                    type: $tokenType,
-                    pattern: $pattern,
-                    length: strlen((string) $value),
-                );
+                if ($prototype === null) {
+                    $tokens[] = new Token($offset, $value, $tokenType, $pattern, strlen((string) $value));
+
+                    continue;
+                }
+
+                $token = clone $prototype;
+                $token->offset = $token->start = $offset;
+                $token->value = $value;
+                $token->length = strlen($value);
+                $token->end = $offset + $token->length;
+                $tokens[] = $token;
             }
         }
 
         return $tokens;
     }
+
+    private function usesBuiltInMatch(Pattern $pattern): bool
+    {
+        static $builtIn = [];
+
+        $class = $pattern::class;
+
+        if (! isset($builtIn[$class])) {
+            $reflection = new ReflectionClass($class);
+
+            $builtIn[$class] = ! $reflection->isAnonymous()
+                && str_starts_with((string) $reflection->getFileName(), dirname(__DIR__) . DIRECTORY_SEPARATOR)
+                && $reflection->getMethod('match')->getFileName() === new ReflectionClass(IsPattern::class)->getFileName()
+                && $this->hasOnlyReadonlyState($reflection);
+        }
+
+        return $builtIn[$class];
+    }
+
+    /**
+     * @param ReflectionClass<object> $reflection
+     */
+    private function hasOnlyReadonlyState(ReflectionClass $reflection): bool
+    {
+        do {
+            foreach ($reflection->getProperties() as $property) {
+                if (! $property->isReadOnly()) {
+                    return false;
+                }
+            }
+        } while ($reflection = $reflection->getParentClass());
+
+        return true;
+    }
 }
diff --git a/src/Tokens/RenderTokens.php b/src/Tokens/RenderTokens.php
index 5c929cb1..3817609d 100644
--- a/src/Tokens/RenderTokens.php
+++ b/src/Tokens/RenderTokens.php
@@ -6,10 +6,11 @@
 
 use Tempest\Highlight\Escape;
 use Tempest\Highlight\Theme;
+use UnitEnum;
 
 final class RenderTokens
 {
-    /** @var array<string, array{string, string}> */
+    /** @var array<class-string, array<string, array{string, string}>> */
     private array $tokenMarkup = [];
 
     public function __construct(
@@ -31,55 +32,53 @@ public function __invoke(
         }
 
         $markup = $this->tokenMarkup;
-        $parts = [];
+        $output = '';
         $cursor = 0;
 
         foreach ($tokens as $currentToken) {
             $relativeOffset = $currentToken->offset - $baseOffset;
 
             if ($relativeOffset > $cursor) {
-                $parts[] = substr($content, $cursor, $relativeOffset - $cursor);
+                $output .= substr($content, $cursor, $relativeOffset - $cursor);
             }
 
-            [$beforeMarkup, $afterMarkup] = $this->getTokenMarkup($currentToken, $markup);
+            $type = $currentToken->type;
 
-            $parts[] = $beforeMarkup;
-            $parts[] = $currentToken->children !== []
-                ? ($this)(
-                    content: $currentToken->value,
-                    tokens: $currentToken->children,
-                    baseOffset: $currentToken->offset,
-                )
-                : $currentToken->value;
-            $parts[] = $afterMarkup;
+            [$beforeMarkup, $afterMarkup] = $type instanceof UnitEnum && isset($markup[$type::class][$type->name])
+                ? $markup[$type::class][$type->name]
+                : $this->getTokenMarkup($type, $markup);
+
+            $output .= $beforeMarkup
+                . ($currentToken->children !== []
+                    ? $this->__invoke($currentToken->value, $currentToken->children, $currentToken->offset)
+                    : $currentToken->value)
+                . $afterMarkup;
 
             $cursor = $relativeOffset + $currentToken->length;
         }
 
-        $contentLength = strlen($content);
-        if ($cursor < $contentLength) {
-            $parts[] = substr($content, $cursor);
+        if ($cursor < strlen($content)) {
+            $output .= substr($content, $cursor);
         }
 
-        return implode('', $parts);
+        return $output;
     }
 
     /**
-     * @param array<string, array{string, string}> $markup
+     * Only enum types are cached: they are finite and their case identifies the markup.
+     *
+     * @param array<class-string, array<string, array{string, string}>> $markup
      * @return array{string, string}
      */
-    private function getTokenMarkup(Token $token, array &$markup): array
+    private function getTokenMarkup(TokenType $type, array &$markup): array
     {
-        if (isset($markup[$token->typeValue])) {
-            return $markup[$token->typeValue];
-        }
+        $tokenMarkup = [Escape::tokens($this->theme->before($type)), Escape::tokens($this->theme->after($type))];
 
-        $beforeMarkup = Escape::tokens($this->theme->before($token->type));
-        $afterMarkup = Escape::tokens($this->theme->after($token->type));
-
-        $markup[$token->typeValue] = [$beforeMarkup, $afterMarkup];
-        $this->tokenMarkup[$token->typeValue] = [$beforeMarkup, $afterMarkup];
+        if ($type instanceof UnitEnum) {
+            $markup[$type::class][$type->name] = $tokenMarkup;
+            $this->tokenMarkup[$type::class][$type->name] = $tokenMarkup;
+        }
 
-        return $markup[$token->typeValue];
+        return $tokenMarkup;
     }
 }
diff --git a/tests/Bench/EdgeCaseBench.php b/tests/Bench/EdgeCaseBench.php
new file mode 100644
index 00000000..76d9722b
--- /dev/null
+++ b/tests/Bench/EdgeCaseBench.php
@@ -0,0 +1,46 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tempest\Highlight\Tests\Bench;
+
+use PhpBench\Attributes as Bench;
+use Tempest\Highlight\Highlighter;
+use Tempest\Highlight\Themes\CssTheme;
+
+/**
+ * Guards inputs that once blew up: unclosed markers, long string literals and very large files.
+ */
+#[Bench\Warmup(1)]
+#[Bench\Iterations(3)]
+#[Bench\OutputTimeUnit('milliseconds')]
+final class EdgeCaseBench
+{
+    private Highlighter $highlighter;
+
+    private string $php;
+
+    public function __construct()
+    {
+        $this->highlighter = new Highlighter(new CssTheme());
+        $this->php = file_get_contents(__DIR__ . '/Fixtures/php.txt');
+    }
+
+    #[Bench\Revs(3)]
+    public function benchUnclosedMarkers(): void
+    {
+        $this->highlighter->parse(str_repeat("{-1: 'neg'}\n", 8_500), 'txt');
+    }
+
+    #[Bench\Revs(5)]
+    public function benchLongStringLiteral(): void
+    {
+        $this->highlighter->parse("<?php\n\$s = '" . str_repeat('a', 7_000) . "';\n" . $this->php, 'php');
+    }
+
+    #[Bench\Revs(1)]
+    public function benchOneMegabytePhp(): void
+    {
+        $this->highlighter->parse(str_repeat($this->php . "\n", 335), 'php');
+    }
+}
diff --git a/tests/HighlighterTest.php b/tests/HighlighterTest.php
index f92e672e..7103ec8e 100644
--- a/tests/HighlighterTest.php
+++ b/tests/HighlighterTest.php
@@ -12,6 +12,8 @@
 use Tempest\Highlight\IsInjection;
 use Tempest\Highlight\Language;
 use Tempest\Highlight\Languages\Php\PhpLanguage;
+use Tempest\Highlight\Languages\Sql\SqlLanguage;
+use Tempest\Highlight\Languages\Text\TextLanguage;
 use Tempest\Highlight\Themes\InlineTheme;
 use Tempest\Highlight\Tokens\TokenTypeEnum;
 
@@ -171,4 +173,49 @@ public function text_language_does_not_use_the_configured_fallback_language(): v
         $this->assertSame('resources/list', $highlighter->parse('resources/list', 'text'));
         $this->assertSame('Sec-Fetch-Site', $highlighter->parse('Sec-Fetch-Site', 'txt'));
     }
+
+    #[Test]
+    #[DataProvider('provide_large_multiline_blocks_are_highlighted_cases')]
+    public function large_multiline_blocks_are_highlighted(string $language, string $before, string $after, string $expected): void
+    {
+        // Large enough to exhaust the PCRE JIT stack with a `(.|\n)*?` pattern
+        $content = $before . str_repeat("lorem ipsum dolor\n", 6000) . $after;
+
+        $this->assertStringContainsString($expected, new Highlighter()->parse($content, $language));
+    }
+
+    public static function provide_large_multiline_blocks_are_highlighted_cases(): iterable
+    {
+        yield 'php comment' => ['php', "<?php\n/*", "*/\n", '<span class="hl-comment">/*'];
+        yield 'php doc comment' => ['php', "<?php\n/**", "*/\n", '<span class="hl-comment">/**'];
+        yield 'javascript comment' => ['javascript', '/*', '*/', '<span class="hl-comment">/*'];
+        yield 'css comment' => ['css', '/*', '*/', '<span class="hl-comment">/*'];
+        yield 'sql comment' => ['sql', '/*', '*/', '<span class="hl-comment">/*'];
+        yield 'xml comment' => ['xml', '<!--', '-->', '<span class="hl-comment">&lt;!--'];
+        yield 'twig comment' => ['twig', '{#', '#}', '<span class="hl-comment">{#'];
+        yield 'blade comment' => ['blade', '{{--', '--}}', '<span class="hl-comment">{{--'];
+        yield 'python string' => ['python', 'x = """', '"""', '<span class="hl-value">&quot;&quot;&quot;'];
+        yield 'html script' => ['html', '<script>', 'const x = 1;</script>', '<span class="hl-keyword">const</span>'];
+        yield 'addition' => ['php', '{+', '+}', '<span class="hl-addition">'];
+    }
+
+    #[Test]
+    public function freed_language_cache_is_not_reused_by_a_new_language(): void
+    {
+        $base = new Highlighter();
+        $base->parse('SELECT * FROM users', new SqlLanguage());
+
+        $highlighter = $base->withGutter();
+        unset($base);
+
+        // Drops the last reference to the SqlLanguage, so PHP can hand its
+        // object id to the next object, here the PhpLanguage below
+        $highlighter->setCurrentLanguage(new TextLanguage());
+        $highlighted = $highlighter->parse('<?php echo $foo;', new PhpLanguage());
+
+        $this->assertSame(
+            '<span class="hl-gutter">1</span><span class="hl-keyword">&lt;?php</span> <span class="hl-keyword">echo</span> <span class="hl-variable">$foo</span>;',
+            $highlighted,
+        );
+    }
 }
diff --git a/tests/Languages/Base/Injections/GutterInjectionStateTest.php b/tests/Languages/Base/Injections/GutterInjectionStateTest.php
new file mode 100644
index 00000000..61394d0f
--- /dev/null
+++ b/tests/Languages/Base/Injections/GutterInjectionStateTest.php
@@ -0,0 +1,47 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tempest\Highlight\Tests\Languages\Base\Injections;
+
+use PHPUnit\Framework\TestCase;
+use Tempest\Highlight\Highlighter;
+
+class GutterInjectionStateTest extends TestCase
+{
+    public function test_reused_gutter_does_not_show_marks_from_a_previous_parse(): void
+    {
+        $highlighter = (new Highlighter())->withGutter();
+
+        $withMarks = $highlighter->parse("a\n{+b+}\nc\n{-d-}\ne", 'txt');
+        $withoutMarks = $highlighter->parse("a\nb\nc\nd\ne", 'txt');
+
+        $this->assertSame(<<<'TXT'
+<span class="hl-gutter">  1</span>a
+<span class="hl-gutter hl-gutter-addition">2 +</span><span class="hl-addition">b</span>
+<span class="hl-gutter">  3</span>c
+<span class="hl-gutter hl-gutter-deletion">4 -</span><span class="hl-deletion">d</span>
+<span class="hl-gutter">  5</span>e
+TXT, $withMarks);
+
+        $this->assertSame(<<<'TXT'
+<span class="hl-gutter">1</span>a
+<span class="hl-gutter">2</span>b
+<span class="hl-gutter">3</span>c
+<span class="hl-gutter">4</span>d
+<span class="hl-gutter">5</span>e
+TXT, $withoutMarks);
+    }
+
+    public function test_gutter_with_invalid_utf8(): void
+    {
+        $input = "<?php echo 'caf\xE9';\necho 1;";
+
+        [$first, $second] = explode("\n", (new Highlighter())->parse($input, 'php'));
+
+        $this->assertSame(
+            '<span class="hl-gutter">1</span>' . $first . "\n" . '<span class="hl-gutter">2</span>' . $second,
+            (new Highlighter())->withGutter()->parse($input, 'php'),
+        );
+    }
+}
diff --git a/tests/Languages/Base/Injections/UnclosedMarkerTest.php b/tests/Languages/Base/Injections/UnclosedMarkerTest.php
new file mode 100644
index 00000000..96e6e006
--- /dev/null
+++ b/tests/Languages/Base/Injections/UnclosedMarkerTest.php
@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tempest\Highlight\Tests\Languages\Base\Injections;
+
+use PHPUnit\Framework\TestCase;
+use Tempest\Highlight\Highlighter;
+
+class UnclosedMarkerTest extends TestCase
+{
+    public function test_diff_markers_after_the_last_closer_stay_plain(): void
+    {
+        $this->assertSame(
+            '<span class="hl-addition">a</span> <span class="hl-deletion">b</span> {+c' . "\n" . '{-d -}} {-e',
+            (new Highlighter())->parse("{+a+} {-b-} {+c\n{-d -}} {-e", 'txt'),
+        );
+    }
+
+    public function test_highlight_markers_after_the_last_closer_stay_plain(): void
+    {
+        $this->assertSame(
+            '<span style="display: none">{*</span><span class="hl-strong">a</span><span style="display: none">*}</span> {*b *}} {*c <span class="x">y</span> {:z:w',
+            (new Highlighter())->parse('{*a*} {*b *}} {*c {:x:y:} {:z:w', 'txt'),
+        );
+    }
+}
diff --git a/tests/Languages/Dockerfile/DockerfileLongLineTest.php b/tests/Languages/Dockerfile/DockerfileLongLineTest.php
new file mode 100644
index 00000000..2c7d5b0f
--- /dev/null
+++ b/tests/Languages/Dockerfile/DockerfileLongLineTest.php
@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tempest\Highlight\Tests\Languages\Dockerfile;
+
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\TestCase;
+use Tempest\Highlight\Highlighter;
+
+final class DockerfileLongLineTest extends TestCase
+{
+    #[DataProvider('provide_long_literal_keeps_later_tokens_cases')]
+    public function test_long_literal_keeps_later_tokens(string $content, string $expected): void
+    {
+        $highlighter = new Highlighter();
+
+        $this->assertStringContainsString($expected, $highlighter->parse($content, 'dockerfile'));
+    }
+
+    public static function provide_long_literal_keeps_later_tokens_cases(): iterable
+    {
+        $long = str_repeat('a', 7000);
+
+        yield 'double quote' => [
+            "RUN [\"{$long}\"]\nRUN [\"x\"]",
+            '<span class="hl-value">&quot;x&quot;</span>',
+        ];
+
+        yield 'single quote' => [
+            "RUN ['{$long}']\nRUN ['x']",
+            "<span class=\"hl-value\">'x'</span>",
+        ];
+    }
+}
diff --git a/tests/Languages/Gdscript/GdscriptLongLineTest.php b/tests/Languages/Gdscript/GdscriptLongLineTest.php
new file mode 100644
index 00000000..3e608e3b
--- /dev/null
+++ b/tests/Languages/Gdscript/GdscriptLongLineTest.php
@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tempest\Highlight\Tests\Languages\Gdscript;
+
+use PHPUnit\Framework\TestCase;
+use Tempest\Highlight\Highlighter;
+
+final class GdscriptLongLineTest extends TestCase
+{
+    public function test_long_comment_keeps_later_comments(): void
+    {
+        $highlighter = new Highlighter();
+
+        $this->assertStringContainsString(
+            '<span class="hl-comment"># x</span>',
+            $highlighter->parse('# ' . str_repeat('a', 14000) . "\n# x", 'gdscript'),
+        );
+    }
+}
diff --git a/tests/Languages/Gdscript/Patterns/CombinedGdscriptKeywordPatternTest.php b/tests/Languages/Gdscript/Patterns/CombinedGdscriptKeywordPatternTest.php
new file mode 100644
index 00000000..54501847
--- /dev/null
+++ b/tests/Languages/Gdscript/Patterns/CombinedGdscriptKeywordPatternTest.php
@@ -0,0 +1,78 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tempest\Highlight\Tests\Languages\Gdscript\Patterns;
+
+use InvalidArgumentException;
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\TestCase;
+use Tempest\Highlight\Languages\Gdscript\Patterns\CombinedGdscriptKeywordPattern;
+use Tempest\Highlight\Languages\Gdscript\Patterns\KeywordPattern;
+use Tempest\Highlight\Tokens\TokenTypeEnum;
+
+final class CombinedGdscriptKeywordPatternTest extends TestCase
+{
+    private const array KEYWORDS = ['class', 'class_name', 'func', 'var', 'if', 'in', 'is', 'not', 'and', 'self', 'PI', 'INF'];
+
+    /**
+     * @param array<array{string, int}> $expected
+     */
+    #[DataProvider('provide_matches_with_offsets_cases')]
+    public function test_matches_with_offsets(string $content, array $expected): void
+    {
+        $matches = new CombinedGdscriptKeywordPattern(self::KEYWORDS)->match($content);
+
+        $this->assertSame($expected, $matches['match']);
+    }
+
+    public static function provide_matches_with_offsets_cases(): iterable
+    {
+        yield 'multiple matches' => ['if x is not y and z', [['if', 0], ['is', 5], ['not', 8], ['and', 14]]];
+        yield 'keyword that prefixes another' => ['class_name Foo', [['class_name', 0]]];
+        yield 'keyword inside identifier' => ['classy inside island variable PIE', []];
+        yield 'keyword next to underscore or digit' => ['var_x func2 _self', []];
+        yield 'keyword next to punctuation' => ['self.x(PI)', [['self', 0], ['PI', 7]]];
+        yield 'case sensitive' => ['Func VAR pi inf', []];
+        yield 'no keywords' => ['x = 1', []];
+    }
+
+    public function test_matches_the_same_tokens_as_one_pattern_per_keyword(): void
+    {
+        $content = file_get_contents(__DIR__ . '/../../../Bench/Fixtures/gdscript.txt');
+
+        $expected = [];
+
+        foreach (self::KEYWORDS as $keyword) {
+            foreach (new KeywordPattern($keyword)->match($content)['match'] as $match) {
+                $expected[] = $match;
+            }
+        }
+
+        $actual = new CombinedGdscriptKeywordPattern(self::KEYWORDS)->match($content)['match'];
+
+        usort($expected, static fn (array $a, array $b): int => $a[1] <=> $b[1]);
+
+        $this->assertNotEmpty($actual);
+        $this->assertSame($expected, $actual);
+    }
+
+    public function test_duplicate_keywords_match_once(): void
+    {
+        $matches = new CombinedGdscriptKeywordPattern(['var', 'var'])->match('var x');
+
+        $this->assertSame([['var', 0]], $matches['match']);
+    }
+
+    public function test_token_type_is_keyword(): void
+    {
+        $this->assertSame(TokenTypeEnum::KEYWORD, new CombinedGdscriptKeywordPattern(['var'])->getTokenType());
+    }
+
+    public function test_requires_a_keyword(): void
+    {
+        $this->expectException(InvalidArgumentException::class);
+
+        new CombinedGdscriptKeywordPattern([]);
+    }
+}
diff --git a/tests/Languages/Graphql/GraphqlLongLineTest.php b/tests/Languages/Graphql/GraphqlLongLineTest.php
new file mode 100644
index 00000000..8ff5e09f
--- /dev/null
+++ b/tests/Languages/Graphql/GraphqlLongLineTest.php
@@ -0,0 +1,44 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tempest\Highlight\Tests\Languages\Graphql;
+
+use PHPUnit\Framework\TestCase;
+use Tempest\Highlight\Highlighter;
+
+final class GraphqlLongLineTest extends TestCase
+{
+    public function test_long_string_keeps_later_strings(): void
+    {
+        $highlighter = new Highlighter();
+
+        $this->assertStringContainsString(
+            '&quot;<span class="hl-value">x</span>&quot;',
+            $highlighter->parse('f(a: "' . str_repeat('a', 7000) . "\")\nf(b: \"x\")", 'graphql'),
+        );
+    }
+
+    public function test_long_word_keeps_later_fields(): void
+    {
+        $highlighter = new Highlighter();
+
+        $this->assertStringContainsString(
+            '<span class="hl-property">field</span>',
+            $highlighter->parse(str_repeat('a', 600000) . "\nfield: String", 'graphql'),
+        );
+    }
+
+    public function test_unterminated_string_with_escaped_quotes_is_parsed_in_linear_time(): void
+    {
+        $highlighter = new Highlighter();
+        $content = 'f(a: "' . str_repeat('text \\" ', 32768) . "\\\n" . 'f(b: "x")';
+
+        $startedAt = hrtime(true);
+        $output = $highlighter->parse($content, 'graphql');
+        $elapsedSeconds = (hrtime(true) - $startedAt) / 1_000_000_000;
+
+        $this->assertStringContainsString('&quot;<span class="hl-value">x</span>&quot;', $output);
+        $this->assertLessThan(1.0, $elapsedSeconds);
+    }
+}
diff --git a/tests/Languages/JavaScript/JavaScriptLongLineTest.php b/tests/Languages/JavaScript/JavaScriptLongLineTest.php
new file mode 100644
index 00000000..1a5a456a
--- /dev/null
+++ b/tests/Languages/JavaScript/JavaScriptLongLineTest.php
@@ -0,0 +1,49 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tempest\Highlight\Tests\Languages\JavaScript;
+
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\TestCase;
+use Tempest\Highlight\Highlighter;
+
+final class JavaScriptLongLineTest extends TestCase
+{
+    #[DataProvider('provide_long_literal_keeps_later_tokens_cases')]
+    public function test_long_literal_keeps_later_tokens(string $language, string $content, string $expected): void
+    {
+        $highlighter = new Highlighter();
+
+        $this->assertStringContainsString($expected, $highlighter->parse($content, $language));
+    }
+
+    public static function provide_long_literal_keeps_later_tokens_cases(): iterable
+    {
+        $long = str_repeat('a', 7000);
+
+        yield 'double quote' => [
+            'javascript',
+            "a = \"{$long}\";\nb = \"x\";",
+            '<span class="hl-value">&quot;x&quot;</span>',
+        ];
+
+        yield 'single quote' => [
+            'javascript',
+            "a = '{$long}';\nb = 'x';",
+            "<span class=\"hl-value\">'x'</span>",
+        ];
+
+        yield 'line comment' => [
+            'javascript',
+            "// {$long}{$long}\n// x",
+            '<span class="hl-comment">// x</span>',
+        ];
+
+        yield 'terraform line comment' => [
+            'terraform',
+            "// {$long}{$long}\n// x",
+            '<span class="hl-comment">// x</span>',
+        ];
+    }
+}
diff --git a/tests/Languages/Php/Injections/PhpGenericTypeInjectionTest.php b/tests/Languages/Php/Injections/PhpGenericTypeInjectionTest.php
new file mode 100644
index 00000000..6dc850ee
--- /dev/null
+++ b/tests/Languages/Php/Injections/PhpGenericTypeInjectionTest.php
@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tempest\Highlight\Tests\Languages\Php\Injections;
+
+use PHPUnit\Framework\TestCase;
+use Tempest\Highlight\Escape;
+use Tempest\Highlight\Highlighter;
+use Tempest\Highlight\Languages\Php\Injections\PhpGenericTypeInjection;
+
+class PhpGenericTypeInjectionTest extends TestCase
+{
+    public function test_generic_type_named_like_theme_markup_does_not_corrupt_earlier_highlights(): void
+    {
+        $generic = fn (string $type): string => Escape::tokens('<span class="hl-generic">') . $type . Escape::tokens('</span>');
+
+        $parsed = new PhpGenericTypeInjection()->parse(' * Wraps <b> in <span>', new Highlighter());
+
+        $this->assertSame(
+            ' * Wraps <' . $generic('b') . '> in <' . $generic('span') . '>',
+            $parsed->content,
+        );
+    }
+}
diff --git a/tests/Languages/Php/PhpLongLineTest.php b/tests/Languages/Php/PhpLongLineTest.php
new file mode 100644
index 00000000..37e848da
--- /dev/null
+++ b/tests/Languages/Php/PhpLongLineTest.php
@@ -0,0 +1,55 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tempest\Highlight\Tests\Languages\Php;
+
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\TestCase;
+use Tempest\Highlight\Highlighter;
+
+final class PhpLongLineTest extends TestCase
+{
+    #[DataProvider('provide_long_literal_keeps_later_tokens_cases')]
+    public function test_long_literal_keeps_later_tokens(string $content, string $expected): void
+    {
+        $highlighter = new Highlighter();
+
+        $this->assertStringContainsString($expected, $highlighter->parse($content, 'php'));
+    }
+
+    public static function provide_long_literal_keeps_later_tokens_cases(): iterable
+    {
+        $long = str_repeat('a', 7000);
+
+        yield 'double quote' => [
+            "<?php \$a = \"{$long}\";\n\$b = \"x\";",
+            '<span class="hl-value">&quot;x&quot;</span>',
+        ];
+
+        yield 'single quote' => [
+            "<?php \$a = '{$long}';\n\$b = 'x';",
+            "<span class=\"hl-value\">'x'</span>",
+        ];
+
+        yield 'escaped double quotes' => [
+            '<?php $a = "' . str_repeat('\\"', 7000) . "\";\n\$b = \"x\";",
+            '<span class="hl-value">&quot;x&quot;</span>',
+        ];
+
+        yield 'line comment' => [
+            "<?php // {$long}{$long}\n// x",
+            '<span class="hl-comment">// x</span>',
+        ];
+    }
+
+    public function test_variable_named_like_keyword_in_parameters(): void
+    {
+        $highlighter = new Highlighter();
+
+        $this->assertSame(
+            '<span class="hl-keyword">&lt;?php</span> <span class="hl-keyword">function</span> <span class="hl-property">swap</span>(<span class="hl-injection">$old, $new, $true</span>) {}',
+            $highlighter->parse('<?php function swap($old, $new, $true) {}', 'php'),
+        );
+    }
+}
diff --git a/tests/Languages/Python/PythonPatternBugsTest.php b/tests/Languages/Python/PythonPatternBugsTest.php
new file mode 100644
index 00000000..beffc4dc
--- /dev/null
+++ b/tests/Languages/Python/PythonPatternBugsTest.php
@@ -0,0 +1,158 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tempest\Highlight\Tests\Languages\Python;
+
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\TestCase;
+use Tempest\Highlight\Highlighter;
+
+final class PythonPatternBugsTest extends TestCase
+{
+    #[DataProvider('provide_highlight_cases')]
+    public function test_highlight(string $content, string $expected): void
+    {
+        $highlighter = new Highlighter();
+
+        $this->assertSame($expected, $highlighter->parse($content, 'python'));
+    }
+
+    public static function provide_highlight_cases(): iterable
+    {
+        yield 'and keyword' => [
+            'a and b',
+            'a <span class="hl-keyword">and</span> b',
+        ];
+
+        yield 'wildcard case' => [
+            'case _:',
+            'case <span class="hl-keyword">_</span>:',
+        ];
+
+        yield 'wildcard case in match block' => [
+            "match x:\n    case _:\n        pass",
+            "match x:\n    case <span class=\"hl-keyword\">_</span>:\n        <span class=\"hl-keyword\">pass</span>",
+        ];
+
+        yield 'underscore parameter' => [
+            'def consume(_: int): pass',
+            '<span class="hl-keyword">def</span> <span class="hl-property">consume</span>(_: <span class="hl-type">int</span>): <span class="hl-keyword">pass</span>',
+        ];
+
+        yield 'underscore annotated variable' => [
+            '_: int = 1',
+            '_: <span class="hl-type">int</span> <span class="hl-operator">=</span> <span class="hl-number">1</span>',
+        ];
+
+        yield 'underscore dictionary key' => [
+            'mapping = {_: "translated"}',
+            'mapping <span class="hl-operator">=</span> {_: <span class="hl-value">&quot;translated&quot;</span>}',
+        ];
+
+        yield 'underscore lambda parameter' => [
+            'lambda _: 0',
+            '<span class="hl-keyword">lambda</span> _: <span class="hl-number">0</span>',
+        ];
+
+        yield 'wildcard case after two spaces' => [
+            "match value:\n    case  _:\n        pass",
+            "match value:\n    case  <span class=\"hl-keyword\">_</span>:\n        <span class=\"hl-keyword\">pass</span>",
+        ];
+
+        yield 'wildcard case after space and tab' => [
+            "match value:\n    case \t_:\n        pass",
+            "match value:\n    case \t<span class=\"hl-keyword\">_</span>:\n        <span class=\"hl-keyword\">pass</span>",
+        ];
+
+        yield 'underscore after comment ending in case' => [
+            "# Special case\n_: int = 1",
+            "<span class=\"hl-comment\"># Special case</span>\n_: <span class=\"hl-type\">int</span> <span class=\"hl-operator\">=</span> <span class=\"hl-number\">1</span>",
+        ];
+
+        yield 'wildcard in or pattern' => [
+            "match x:\n    case 1 | _:\n        pass",
+            "match x:\n    case <span class=\"hl-number\">1</span> <span class=\"hl-operator\">|</span> <span class=\"hl-keyword\">_</span>:\n        <span class=\"hl-keyword\">pass</span>",
+        ];
+
+        yield 'wildcard in sequence pattern' => [
+            "match x:\n    case (_, x):\n        pass",
+            "match x:\n    case (<span class=\"hl-keyword\">_</span>, x):\n        <span class=\"hl-keyword\">pass</span>",
+        ];
+
+        yield 'wildcard star pattern' => [
+            "match x:\n    case [x, *_]:\n        pass",
+            "match x:\n    case [x, <span class=\"hl-operator\">*</span><span class=\"hl-keyword\">_</span>]:\n        <span class=\"hl-keyword\">pass</span>",
+        ];
+
+        yield 'wildcard in class pattern' => [
+            "match x:\n    case Point(x=_):\n        pass",
+            "match x:\n    case Point(<span class=\"hl-variable\">x</span><span class=\"hl-operator\">=</span><span class=\"hl-keyword\">_</span>):\n        <span class=\"hl-keyword\">pass</span>",
+        ];
+
+        yield 'wildcard in mapping pattern' => [
+            "match x:\n    case {\"k\": _}:\n        pass",
+            "match x:\n    case {<span class=\"hl-value\">&quot;k&quot;</span>: <span class=\"hl-keyword\">_</span>}:\n        <span class=\"hl-keyword\">pass</span>",
+        ];
+
+        yield 'underscore in guard' => [
+            "match x:\n    case _ if _ > 0:\n        pass",
+            "match x:\n    case <span class=\"hl-keyword\">_</span> <span class=\"hl-keyword\">if</span> _ <span class=\"hl-operator\">&gt;</span> <span class=\"hl-number\">0</span>:\n        <span class=\"hl-keyword\">pass</span>",
+        ];
+
+        yield 'underscore in one-line case body' => [
+            "match x:\n    case _: return _",
+            "match x:\n    case <span class=\"hl-keyword\">_</span>: <span class=\"hl-keyword\">return</span> _",
+        ];
+
+        yield 'underscore in case string' => [
+            "match x:\n    case \"_\":\n        pass",
+            "match x:\n    case <span class=\"hl-value\">&quot;_&quot;</span>:\n        <span class=\"hl-keyword\">pass</span>",
+        ];
+
+        yield 'underscore in case comment' => [
+            "match x:\n    case _:  # _ comment\n        pass",
+            "match x:\n    case <span class=\"hl-keyword\">_</span>:  <span class=\"hl-comment\"># _ comment</span>\n        <span class=\"hl-keyword\">pass</span>",
+        ];
+
+        yield 'underscore value pattern attribute' => [
+            "match x:\n    case Color._:\n        pass",
+            "match x:\n    case Color._:\n        <span class=\"hl-keyword\">pass</span>",
+        ];
+
+        yield 'case identifier with lambda' => [
+            "case = lambda _: _",
+            "case <span class=\"hl-operator\">=</span> <span class=\"hl-keyword\">lambda</span> _: _",
+        ];
+
+        yield 'case outside match block' => [
+            "if x:\n    case _:\n        pass",
+            "<span class=\"hl-keyword\">if</span> x:\n    case _:\n        <span class=\"hl-keyword\">pass</span>",
+        ];
+
+        yield 'case subscript assigned a lambda' => [
+            "case = {}\ncase[_] = lambda _: _",
+            "case <span class=\"hl-operator\">=</span> {}\ncase[_] <span class=\"hl-operator\">=</span> <span class=\"hl-keyword\">lambda</span> _: _",
+        ];
+
+        yield 'case call subscript annotation' => [
+            "case(_)[0]: int = 1",
+            "case(_)[<span class=\"hl-number\">0</span>]: <span class=\"hl-type\">int</span> <span class=\"hl-operator\">=</span> <span class=\"hl-number\">1</span>",
+        ];
+
+        yield 'underscore attribute in mapping key' => [
+            "match x:\n    case {_.y: _, 1: z}:\n        pass",
+            "match x:\n    case {_.y: <span class=\"hl-keyword\">_</span>, <span class=\"hl-number\">1</span>: z}:\n        <span class=\"hl-keyword\">pass</span>",
+        ];
+
+        yield 'wildcard after multi-line match subject' => [
+            "match (x,\ny):\n    case _:\n        pass",
+            "match (x,\ny):\n    case <span class=\"hl-keyword\">_</span>:\n        <span class=\"hl-keyword\">pass</span>",
+        ];
+
+        yield 'wildcard after multi-line string in case body' => [
+            "match x:\n    case 1:\n        s = \"\"\"\ndoc\n\"\"\"\n    case _:\n        pass",
+            "match x:\n    case <span class=\"hl-number\">1</span>:\n        s <span class=\"hl-operator\">=</span> <span class=\"hl-value\">&quot;&quot;&quot;\ndoc\n&quot;&quot;&quot;</span>\n    case <span class=\"hl-keyword\">_</span>:\n        <span class=\"hl-keyword\">pass</span>",
+        ];
+    }
+}
diff --git a/tests/Languages/Sql/SqlLongLineTest.php b/tests/Languages/Sql/SqlLongLineTest.php
new file mode 100644
index 00000000..43e7e926
--- /dev/null
+++ b/tests/Languages/Sql/SqlLongLineTest.php
@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tempest\Highlight\Tests\Languages\Sql;
+
+use PHPUnit\Framework\TestCase;
+use Tempest\Highlight\Highlighter;
+
+final class SqlLongLineTest extends TestCase
+{
+    public function test_long_comment_keeps_later_comments(): void
+    {
+        $highlighter = new Highlighter();
+
+        $this->assertStringContainsString(
+            '<span class="hl-comment">-- x</span>',
+            $highlighter->parse('-- ' . str_repeat('a', 14000) . "\n-- x", 'sql'),
+        );
+    }
+}
diff --git a/tests/Languages/Twig/Patterns/CombinedTwigKeywordPatternTest.php b/tests/Languages/Twig/Patterns/CombinedTwigKeywordPatternTest.php
new file mode 100644
index 00000000..dac0f6b7
--- /dev/null
+++ b/tests/Languages/Twig/Patterns/CombinedTwigKeywordPatternTest.php
@@ -0,0 +1,78 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tempest\Highlight\Tests\Languages\Twig\Patterns;
+
+use InvalidArgumentException;
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\TestCase;
+use Tempest\Highlight\Languages\Twig\Patterns\CombinedTwigKeywordPattern;
+use Tempest\Highlight\Languages\Twig\Patterns\TwigKeywordPattern;
+use Tempest\Highlight\Tokens\TokenTypeEnum;
+
+final class CombinedTwigKeywordPatternTest extends TestCase
+{
+    private const array KEYWORDS = ['set', 'if', 'endif', 'end', 'for', 'endfor', 'in', 'as', 'with', 'endwith'];
+
+    /**
+     * @param array<array{string, int}> $expected
+     */
+    #[DataProvider('provide_matches_with_offsets_cases')]
+    public function test_matches_with_offsets(string $content, array $expected): void
+    {
+        $matches = new CombinedTwigKeywordPattern(self::KEYWORDS)->match($content);
+
+        $this->assertSame($expected, $matches['match']);
+    }
+
+    public static function provide_matches_with_offsets_cases(): iterable
+    {
+        yield 'multiple matches' => ['for item in items', [['for', 0], ['in', 9]]];
+        yield 'keyword that prefixes another' => ['endif end endfor', [['endif', 0], ['end', 6], ['endfor', 10]]];
+        yield 'keyword inside identifier' => ['settings ending format inside', []];
+        yield 'keyword next to underscore or digit' => ['set_x if1 _for', []];
+        yield 'keyword next to punctuation' => ['{%if(x)%}{%endif%}', [['if', 2], ['endif', 11]]];
+        yield 'case sensitive' => ['SET If FOR', []];
+        yield 'no keywords' => ['{{ name }}', []];
+    }
+
+    public function test_matches_the_same_tokens_as_one_pattern_per_keyword(): void
+    {
+        $content = file_get_contents(__DIR__ . '/../../../Bench/Fixtures/twig.txt');
+
+        $expected = [];
+
+        foreach (self::KEYWORDS as $keyword) {
+            foreach (new TwigKeywordPattern($keyword)->match($content)['match'] as $match) {
+                $expected[] = $match;
+            }
+        }
+
+        $actual = new CombinedTwigKeywordPattern(self::KEYWORDS)->match($content)['match'];
+
+        usort($expected, static fn (array $a, array $b): int => $a[1] <=> $b[1]);
+
+        $this->assertNotEmpty($actual);
+        $this->assertSame($expected, $actual);
+    }
+
+    public function test_duplicate_keywords_match_once(): void
+    {
+        $matches = new CombinedTwigKeywordPattern(['if', 'if'])->match('if x');
+
+        $this->assertSame([['if', 0]], $matches['match']);
+    }
+
+    public function test_token_type_is_keyword(): void
+    {
+        $this->assertSame(TokenTypeEnum::KEYWORD, new CombinedTwigKeywordPattern(['if'])->getTokenType());
+    }
+
+    public function test_requires_a_keyword(): void
+    {
+        $this->expectException(InvalidArgumentException::class);
+
+        new CombinedTwigKeywordPattern([]);
+    }
+}
diff --git a/tests/Languages/Yaml/YamlLongLineTest.php b/tests/Languages/Yaml/YamlLongLineTest.php
new file mode 100644
index 00000000..f864006b
--- /dev/null
+++ b/tests/Languages/Yaml/YamlLongLineTest.php
@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tempest\Highlight\Tests\Languages\Yaml;
+
+use PHPUnit\Framework\TestCase;
+use Tempest\Highlight\Highlighter;
+
+final class YamlLongLineTest extends TestCase
+{
+    public function test_long_comment_keeps_later_comments(): void
+    {
+        $highlighter = new Highlighter();
+
+        $this->assertStringContainsString(
+            '<span class="hl-comment"># x</span>',
+            $highlighter->parse('# ' . str_repeat('a', 14000) . "\n# x", 'yaml'),
+        );
+    }
+}
diff --git a/tests/Tokens/CompiledPatternsTest.php b/tests/Tokens/CompiledPatternsTest.php
new file mode 100644
index 00000000..b0035c9d
--- /dev/null
+++ b/tests/Tokens/CompiledPatternsTest.php
@@ -0,0 +1,127 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tempest\Highlight\Tests\Tokens;
+
+use ArrayObject;
+use PHPUnit\Framework\Attributes\Test;
+use PHPUnit\Framework\TestCase;
+use Tempest\Highlight\Highlighter;
+use Tempest\Highlight\IsPattern;
+use Tempest\Highlight\Language;
+use Tempest\Highlight\Languages\Php\Patterns\KeywordPattern;
+use Tempest\Highlight\Pattern;
+use Tempest\Highlight\Tests\Tokens\Fixtures\ConfigurablePattern;
+use Tempest\Highlight\Tests\Tokens\Fixtures\CustomMatchPattern;
+use Tempest\Highlight\Tokens\TokenTypeEnum;
+
+class CompiledPatternsTest extends TestCase
+{
+    #[Test]
+    public function overridden_match_is_still_called(): void
+    {
+        $highlighter = new Highlighter();
+        $language = $this->language([new CustomMatchPattern()]);
+
+        $this->assertSame('foo <span class="hl-keyword">b</span>ar', $highlighter->parse('foo bar', $language));
+        $this->assertSame('foo <span class="hl-keyword">b</span>ar', $highlighter->parse('foo bar', $language));
+    }
+
+    #[Test]
+    public function third_party_patterns_are_asked_for_their_pattern_and_type_on_every_parse(): void
+    {
+        $pattern = new class () implements Pattern {
+            use IsPattern;
+
+            public string $word = 'foo';
+
+            public TokenTypeEnum $type = TokenTypeEnum::KEYWORD;
+
+            public function getPattern(): string
+            {
+                return "(?<match>{$this->word})";
+            }
+
+            public function getTokenType(): TokenTypeEnum
+            {
+                return $this->type;
+            }
+        };
+
+        $highlighter = new Highlighter();
+        $language = $this->language([$pattern]);
+
+        $this->assertSame('<span class="hl-keyword">foo</span> bar', $highlighter->parse('foo bar', $language));
+
+        $pattern->word = 'bar';
+        $pattern->type = TokenTypeEnum::TYPE;
+
+        $this->assertSame('foo <span class="hl-type">bar</span>', $highlighter->parse('foo bar', $language));
+    }
+
+    #[Test]
+    public function built_in_patterns_with_mutable_state_are_asked_again_on_every_parse(): void
+    {
+        $pattern = new KeywordPattern('select');
+        $highlighter = new Highlighter();
+        $language = $this->language([$pattern]);
+
+        $this->assertSame('<span class="hl-keyword">select</span> SELECT;', $highlighter->parse('select SELECT;', $language));
+
+        $pattern->caseInsensitive();
+
+        $this->assertSame(
+            '<span class="hl-keyword">select</span> <span class="hl-keyword">SELECT</span>;',
+            $highlighter->parse('select SELECT;', $language),
+        );
+    }
+
+    #[Test]
+    public function patterns_outside_the_package_are_asked_again_on_every_parse_even_in_its_namespace(): void
+    {
+        $config = new ArrayObject(['word' => 'foo', 'type' => TokenTypeEnum::KEYWORD]);
+        $highlighter = new Highlighter();
+        $language = $this->language([new ConfigurablePattern($config)]);
+
+        $this->assertSame('<span class="hl-keyword">foo</span> bar', $highlighter->parse('foo bar', $language));
+
+        $config['word'] = 'bar';
+        $config['type'] = TokenTypeEnum::TYPE;
+
+        $this->assertSame('foo <span class="hl-type">bar</span>', $highlighter->parse('foo bar', $language));
+    }
+
+    /**
+     * @param Pattern[] $patterns
+     */
+    private function language(array $patterns): Language
+    {
+        return new readonly class ($patterns) implements Language {
+            public function __construct(
+                private array $patterns,
+            ) {
+            }
+
+            public function getName(): string
+            {
+                return 'compiled-patterns-test';
+            }
+
+            public function getAliases(): array
+            {
+                return [];
+            }
+
+            public function getInjections(): array
+            {
+                return [];
+            }
+
+            public function getPatterns(): array
+            {
+                return $this->patterns;
+            }
+        };
+    }
+}
diff --git a/tests/Tokens/Fixtures/ConfigurablePattern.php b/tests/Tokens/Fixtures/ConfigurablePattern.php
new file mode 100644
index 00000000..4003ebf7
--- /dev/null
+++ b/tests/Tokens/Fixtures/ConfigurablePattern.php
@@ -0,0 +1,33 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tempest\Highlight\Tests\Tokens\Fixtures;
+
+use ArrayObject;
+use Tempest\Highlight\IsPattern;
+use Tempest\Highlight\Pattern;
+use Tempest\Highlight\Tokens\TokenTypeEnum;
+
+final readonly class ConfigurablePattern implements Pattern
+{
+    use IsPattern;
+
+    /**
+     * @param ArrayObject<string, mixed> $config
+     */
+    public function __construct(
+        private ArrayObject $config,
+    ) {
+    }
+
+    public function getPattern(): string
+    {
+        return "(?<match>{$this->config['word']})";
+    }
+
+    public function getTokenType(): TokenTypeEnum
+    {
+        return $this->config['type'];
+    }
+}
diff --git a/tests/Tokens/Fixtures/CustomMatchPattern.php b/tests/Tokens/Fixtures/CustomMatchPattern.php
new file mode 100644
index 00000000..ef37c79a
--- /dev/null
+++ b/tests/Tokens/Fixtures/CustomMatchPattern.php
@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tempest\Highlight\Tests\Tokens\Fixtures;
+
+use Tempest\Highlight\IsPattern;
+use Tempest\Highlight\Pattern;
+use Tempest\Highlight\Tokens\TokenTypeEnum;
+
+final class CustomMatchPattern implements Pattern
+{
+    use IsPattern;
+
+    public function getPattern(): string
+    {
+        return '(?<match>foo)';
+    }
+
+    public function match(string $content): array
+    {
+        return ['match' => [['b', 4]]];
+    }
+
+    public function getTokenType(): TokenTypeEnum
+    {
+        return TokenTypeEnum::KEYWORD;
+    }
+}
diff --git a/tests/Tokens/Fixtures/RequiresBarInjection.php b/tests/Tokens/Fixtures/RequiresBarInjection.php
new file mode 100644
index 00000000..389831b3
--- /dev/null
+++ b/tests/Tokens/Fixtures/RequiresBarInjection.php
@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tempest\Highlight\Tests\Tokens\Fixtures;
+
+use Tempest\Highlight\Highlighter;
+use Tempest\Highlight\Injection;
+use Tempest\Highlight\IsInjection;
+use Tempest\Highlight\RequiresSubstring;
+
+/** Deliberately declares a substring its regex does not need, so skipping it is visible in the output. */
+#[RequiresSubstring('bar')]
+class RequiresBarInjection implements Injection
+{
+    use IsInjection;
+
+    public function getPattern(): string
+    {
+        return '(?<match>foo)';
+    }
+
+    public function parseContent(string $content, Highlighter $highlighter): string
+    {
+        return strtoupper($content);
+    }
+}
diff --git a/tests/Tokens/Fixtures/RequiresBarPattern.php b/tests/Tokens/Fixtures/RequiresBarPattern.php
new file mode 100644
index 00000000..93b08ea7
--- /dev/null
+++ b/tests/Tokens/Fixtures/RequiresBarPattern.php
@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tempest\Highlight\Tests\Tokens\Fixtures;
+
+use Tempest\Highlight\IsPattern;
+use Tempest\Highlight\Pattern;
+use Tempest\Highlight\RequiresSubstring;
+use Tempest\Highlight\Tokens\TokenTypeEnum;
+
+/** Deliberately declares a substring its regex does not need, so skipping it is visible in the output. */
+#[RequiresSubstring('bar')]
+class RequiresBarPattern implements Pattern
+{
+    use IsPattern;
+
+    public function getPattern(): string
+    {
+        return '(?<match>foo)';
+    }
+
+    public function getTokenType(): TokenTypeEnum
+    {
+        return TokenTypeEnum::KEYWORD;
+    }
+}
diff --git a/tests/Tokens/GroupTokensSortTest.php b/tests/Tokens/GroupTokensSortTest.php
new file mode 100644
index 00000000..270b084f
--- /dev/null
+++ b/tests/Tokens/GroupTokensSortTest.php
@@ -0,0 +1,83 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tempest\Highlight\Tests\Tokens;
+
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\Attributes\Test;
+use PHPUnit\Framework\TestCase;
+use ReflectionMethod;
+use Tempest\Highlight\Tokens\GroupTokens;
+use Tempest\Highlight\Tokens\Token;
+use Tempest\Highlight\Tokens\TokenTypeEnum;
+
+class GroupTokensSortTest extends TestCase
+{
+    #[Test]
+    #[DataProvider('provide_sort_order_is_start_ascending_then_end_descending_then_original_index_cases')]
+    public function sort_order_is_start_ascending_then_end_descending_then_original_index(array $tokens): void
+    {
+        $sorted = new ReflectionMethod(GroupTokens::class, 'sortTokens')->invoke(new GroupTokens(), $tokens);
+
+        $this->assertSame(
+            array_map(spl_object_id(...), $this->referenceSort($tokens)),
+            array_map(spl_object_id(...), $sorted),
+        );
+    }
+
+    public static function provide_sort_order_is_start_ascending_then_end_descending_then_original_index_cases(): iterable
+    {
+        mt_srand(42);
+
+        for ($set = 0; $set < 20; $set++) {
+            $tokens = [];
+
+            for ($i = 0, $count = mt_rand(2, 300); $i < $count; $i++) {
+                $offset = mt_rand(-1, 60);
+                $tokens[] = new Token($offset, str_repeat('x', $offset === -1 ? 0 : mt_rand(0, 8)), TokenTypeEnum::KEYWORD);
+            }
+
+            yield "random {$set}" => [$tokens];
+        }
+
+        $duplicate = new Token(3, 'abc', TokenTypeEnum::TYPE);
+
+        yield 'duplicates and zero length' => [[
+            new Token(3, '', TokenTypeEnum::KEYWORD),
+            $duplicate,
+            new Token(3, 'abc', TokenTypeEnum::KEYWORD),
+            new Token(-1, '', TokenTypeEnum::KEYWORD),
+            new Token(0, 'abcd', TokenTypeEnum::KEYWORD),
+            new Token(3, '', TokenTypeEnum::TYPE),
+            $duplicate,
+        ]];
+
+        yield 'unmatched group offset before the widest token' => [[
+            new Token(0, 'abcdef', TokenTypeEnum::KEYWORD),
+            new Token(-1, '', TokenTypeEnum::KEYWORD),
+        ]];
+
+        yield 'range too large for a packed key' => [[
+            new Token(4_000_000_000, 'b', TokenTypeEnum::KEYWORD),
+            new Token(0, 'aa', TokenTypeEnum::KEYWORD),
+            new Token(0, 'a', TokenTypeEnum::KEYWORD),
+            new Token(0, 'aa', TokenTypeEnum::TYPE),
+        ]];
+    }
+
+    /**
+     * @param Token[] $tokens
+     * @return Token[]
+     */
+    private function referenceSort(array $tokens): array
+    {
+        $starts = array_map(fn (Token $token) => $token->start, $tokens);
+        $negatedEnds = array_map(fn (Token $token) => -$token->end, $tokens);
+        $indices = array_keys($tokens);
+
+        array_multisort($starts, SORT_ASC, SORT_NUMERIC, $negatedEnds, SORT_ASC, SORT_NUMERIC, $indices, SORT_ASC, SORT_NUMERIC, $tokens);
+
+        return $tokens;
+    }
+}
diff --git a/tests/Tokens/GroupTokensTest.php b/tests/Tokens/GroupTokensTest.php
index c6c8b6f7..e3507a32 100644
--- a/tests/Tokens/GroupTokensTest.php
+++ b/tests/Tokens/GroupTokensTest.php
@@ -46,4 +46,19 @@ public function test_exact_overlaps_within_children(): void
         $this->assertCount(1, $tokens);
         $this->assertCount(3, $tokens[0]->children);
     }
+
+    public function test_longer_token_wins_at_offsets_beyond_float_precision(): void
+    {
+        $tokens = [
+            new Token(0, 'a', TokenTypeEnum::KEYWORD),
+            new Token(100_000_000, '/', TokenTypeEnum::OPERATOR),
+            new Token(100_000_001, '/', TokenTypeEnum::OPERATOR),
+            new Token(100_000_000, '//', TokenTypeEnum::COMMENT),
+        ];
+
+        $grouped = (new GroupTokens())($tokens);
+
+        $this->assertCount(2, $grouped);
+        $this->assertSame(TokenTypeEnum::COMMENT, $grouped[1]->type);
+    }
 }
diff --git a/tests/Tokens/RenderTokensMarkupCacheTest.php b/tests/Tokens/RenderTokensMarkupCacheTest.php
new file mode 100644
index 00000000..1f1c9170
--- /dev/null
+++ b/tests/Tokens/RenderTokensMarkupCacheTest.php
@@ -0,0 +1,65 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tempest\Highlight\Tests\Tokens;
+
+use PHPUnit\Framework\Attributes\Test;
+use PHPUnit\Framework\TestCase;
+use ReflectionProperty;
+use Tempest\Highlight\Theme;
+use Tempest\Highlight\Themes\CssTheme;
+use Tempest\Highlight\Tokens\DynamicTokenType;
+use Tempest\Highlight\Tokens\RenderTokens;
+use Tempest\Highlight\Tokens\Token;
+use Tempest\Highlight\Tokens\TokenType;
+use Tempest\Highlight\Tokens\TokenTypeEnum;
+
+class RenderTokensMarkupCacheTest extends TestCase
+{
+    #[Test]
+    public function custom_token_type_with_a_built_in_value_gets_its_own_markup(): void
+    {
+        $theme = new class () implements Theme {
+            public function before(TokenType $tokenType): string
+            {
+                return '[' . ($tokenType instanceof TokenTypeEnum ? 'enum' : 'custom') . ']';
+            }
+
+            public function after(TokenType $tokenType): string
+            {
+                return '[/]';
+            }
+
+            public function escape(string $content): string
+            {
+                return $content;
+            }
+        };
+
+        $render = new RenderTokens($theme);
+
+        $this->assertSame('[enum]a[/]', $render('a', [new Token(0, 'a', TokenTypeEnum::KEYWORD)]));
+        $this->assertSame('[custom]a[/]', $render('a', [new Token(0, 'a', new DynamicTokenType('keyword'))]));
+        $this->assertSame('[enum]a[/] [custom]b[/]', $render('a b', [
+            new Token(0, 'a', TokenTypeEnum::KEYWORD),
+            new Token(2, 'b', new DynamicTokenType('keyword')),
+        ]));
+    }
+
+    #[Test]
+    public function markup_cache_does_not_grow_with_custom_class_names(): void
+    {
+        $render = new RenderTokens(new CssTheme());
+
+        for ($i = 0; $i < 100; $i++) {
+            $render('a', [new Token(0, 'a', new DynamicTokenType("hl-custom-{$i}"))]);
+        }
+
+        $render('a', [new Token(0, 'a', TokenTypeEnum::KEYWORD)]);
+
+        $cache = new ReflectionProperty(RenderTokens::class, 'tokenMarkup')->getValue($render);
+
+        $this->assertLessThan(10, count($cache, COUNT_RECURSIVE));
+    }
+}
diff --git a/tests/Tokens/RequiresSubstringTest.php b/tests/Tokens/RequiresSubstringTest.php
new file mode 100644
index 00000000..198f4a50
--- /dev/null
+++ b/tests/Tokens/RequiresSubstringTest.php
@@ -0,0 +1,165 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tempest\Highlight\Tests\Tokens;
+
+use PHPUnit\Framework\Attributes\Test;
+use PHPUnit\Framework\TestCase;
+use Tempest\Highlight\After;
+use Tempest\Highlight\Highlighter;
+use Tempest\Highlight\Injection;
+use Tempest\Highlight\IsInjection;
+use Tempest\Highlight\IsPattern;
+use Tempest\Highlight\Language;
+use Tempest\Highlight\Pattern;
+use Tempest\Highlight\RequiresSubstring;
+use Tempest\Highlight\Tests\Tokens\Fixtures\RequiresBarInjection;
+use Tempest\Highlight\Tests\Tokens\Fixtures\RequiresBarPattern;
+use Tempest\Highlight\Tokens\TokenTypeEnum;
+
+class RequiresSubstringTest extends TestCase
+{
+    #[Test]
+    public function pattern_is_skipped_when_content_lacks_every_required_substring(): void
+    {
+        $highlighter = new Highlighter();
+        $language = $this->language(patterns: [new RequiresBarPattern()]);
+
+        $this->assertSame('foo', $highlighter->parse('foo', $language));
+        $this->assertSame('foo BAR', $highlighter->parse('foo BAR', $language));
+        $this->assertSame('<span class="hl-keyword">foo</span> bar', $highlighter->parse('foo bar', $language));
+    }
+
+    #[Test]
+    public function any_one_of_the_required_substrings_is_enough(): void
+    {
+        $pattern = new #[RequiresSubstring('bar', 'baz')] class () implements Pattern {
+            use IsPattern;
+
+            public function getPattern(): string
+            {
+                return '(?<match>foo)';
+            }
+
+            public function getTokenType(): TokenTypeEnum
+            {
+                return TokenTypeEnum::KEYWORD;
+            }
+        };
+
+        $highlighter = new Highlighter();
+        $language = $this->language(patterns: [$pattern]);
+
+        $this->assertSame('foo', $highlighter->parse('foo', $language));
+        $this->assertSame('<span class="hl-keyword">foo</span> baz', $highlighter->parse('foo baz', $language));
+    }
+
+    #[Test]
+    public function empty_attribute_means_no_requirement(): void
+    {
+        $pattern = new #[RequiresSubstring()] class () implements Pattern {
+            use IsPattern;
+
+            public function getPattern(): string
+            {
+                return '(?<match>foo)';
+            }
+
+            public function getTokenType(): TokenTypeEnum
+            {
+                return TokenTypeEnum::KEYWORD;
+            }
+        };
+
+        $highlighter = new Highlighter();
+        $language = $this->language(patterns: [$pattern]);
+
+        $this->assertSame('<span class="hl-keyword">foo</span>', $highlighter->parse('foo', $language));
+    }
+
+    #[Test]
+    public function before_injection_is_skipped_when_content_lacks_every_required_substring(): void
+    {
+        $highlighter = new Highlighter();
+        $language = $this->language(injections: [new RequiresBarInjection()]);
+
+        $this->assertSame('foo', $highlighter->parse('foo', $language));
+        $this->assertSame('FOO bar', $highlighter->parse('foo bar', $language));
+    }
+
+    #[Test]
+    public function after_injection_is_skipped_when_content_lacks_every_required_substring(): void
+    {
+        $injection = new #[After(), RequiresSubstring('bar')] class () implements Injection {
+            use IsInjection;
+
+            public function getPattern(): string
+            {
+                return '(?<match>foo)';
+            }
+
+            public function parseContent(string $content, Highlighter $highlighter): string
+            {
+                return strtoupper($content);
+            }
+        };
+
+        $highlighter = new Highlighter();
+        $language = $this->language(injections: [$injection]);
+
+        $this->assertSame('foo', $highlighter->parse('foo', $language));
+        $this->assertSame('FOO bar', $highlighter->parse('foo bar', $language));
+    }
+
+    #[Test]
+    public function subclasses_do_not_inherit_the_requirement(): void
+    {
+        $highlighter = new Highlighter();
+        $language = $this->language(
+            patterns: [new class () extends RequiresBarPattern {}],
+            injections: [new class () extends RequiresBarInjection {}],
+        );
+
+        $this->assertSame('FOO', $highlighter->parse('foo', $language));
+
+        $language = $this->language(patterns: [new class () extends RequiresBarPattern {}]);
+
+        $this->assertSame('<span class="hl-keyword">foo</span>', $highlighter->parse('foo', $language));
+    }
+
+    /**
+     * @param Pattern[] $patterns
+     * @param Injection[] $injections
+     */
+    private function language(array $patterns = [], array $injections = []): Language
+    {
+        return new readonly class ($patterns, $injections) implements Language {
+            public function __construct(
+                private array $patterns,
+                private array $injections,
+            ) {
+            }
+
+            public function getName(): string
+            {
+                return 'requires-substring-test';
+            }
+
+            public function getAliases(): array
+            {
+                return [];
+            }
+
+            public function getInjections(): array
+            {
+                return $this->injections;
+            }
+
+            public function getPatterns(): array
+            {
+                return $this->patterns;
+            }
+        };
+    }
+}