Use Biome for code formatting to close #743

biome.json

@@ -0,0 +1,68 @@
+{
+	"assist": {
+		"actions": {
+			"source": {
+				"organizeImports": "off"
+			}
+		}
+	},
+	"formatter": {
+		"indentStyle": "tab",
+		"lineWidth": 100,
+		"bracketSpacing": false
+	},
+	"javascript": {
+		"formatter": {
+			"quoteStyle": "single",
+			"trailingCommas": "es5",
+			"arrowParentheses": "asNeeded"
+		}
+	},
+	"json": {
+		"formatter": {"indentStyle": "tab"}
+	},
+	"linter": {
+		"enabled": true,
+		"includes": ["**", "!bench/**", "!test/manual/**"],
+		"rules": {
+			"correctness": {
+				"preset": "recommended"
+			},
+			"suspicious": {
+				"preset": "recommended",
+				"noApproximativeNumericConstant": "off",
+				"noExplicitAny": "off"
+			},
+			"style": {
+				"preset": "recommended",
+				"useTemplate": "off"
+			},
+			"complexity": {
+				"preset": "recommended"
+			}
+		}
+	},
+	"overrides": [
+		{
+			"includes": ["test/**"],
+			"linter": {
+				"rules": {
+					"correctness": {
+						"noUnusedVariables": "off",
+						"noUnusedImports": "off",
+						"noUnusedFunctionParameters": "off"
+					},
+					"suspicious": {
+						"noImplicitAnyLet": "off"
+					},
+					"complexity": {
+						"useLiteralKeys": "off"
+					}
+				}
+			}
+		}
+	],
+	"files": {
+		"includes": ["**", "!**/dist", "!**/bin", "!**/node_modules"]
+	}
+}

devguide.md

@@ -10,6 +10,7 @@ How we like the code in RexReplace to be.
 - **Comments say why, not what.** Write them in plain, simple English. Leave the comment out if the code already says it.
 - **No sloppy shortcuts.** If two cases need different calls, write a plain `if`/`else` instead of one call that only half fits both.
 - **Everything is printed with `write()` in `src/output.ts`,** so `--nl` knows how each stream ends.
+- **The engine never touches the process.** It resolves with the status report of the run, or throws a panic when the run can not go on. Only `src/cli.ts` reads `argv` and stdin, sets the exit code and ends the process.
 - **stdout is the result.** That is the names of the affected files, or the content from `--output`, `--output-match` or piped data. Everything else goes to stderr, so the result can always be piped.
 
 ## Telling what is going on
@@ -21,22 +22,19 @@ All output goes through `src/output.ts`. Pick the function by who the message is
 | `print(item, delimiter, tail, stream)` | Always | The result. Puts the delimiter after each item, or only between them without a tail. Without a delimiter it is a line break, unless the item already ends with one. | A name, the content of a file, a match |
 | `printDone()` | At the end of a run, also when it is stopped | Ends stdout and stderr with a line break when `--nl` is set | |
 | `info(name)` | Unless `--quiet` | The name of an affected file. stdout, or stderr when stdout has content. | `a.md` |
-| `warn(msg)` | Unless `--quiet` | Something is likely a mistake, but the run goes on | `Data is piped in, but no flag tells what to do with it` |
-| `error(msg, data)` | Unless `--quiet-total` | Something went wrong. The run goes on, unless `--halt` is set. | `File not found: a.md` |
-| `die(msg, data, help)` | Unless `--quiet-total` | Something went wrong and the run can not go on. Exits with 1. | `No data piped into replacement` |
-| `chat(msg)` | `--verbose` (or `--debug`) | The user: what happens to each file | `Open sync: a.md`, `Nothing changed in: a.md` |
-| `debug(data)` | `--debug` | The developer: what happens inside, at points that matter | `Work on content from: a.md` |
-| `step(data)` | `--verbose` and `--debug` | The developer: a trace of every step, with the data at that step | `Get final regex`, the full config |
-
-- The three levels of telling go from little to a lot: `chat`, then `debug`, then `step`.
-- `chat` falls back to `debug` without `--verbose`, so `--debug` alone also shows what happens to each file.
-- `debug` and `step` print their data as JSON. That keeps line breaks and spaces visible.
-- `chat`, `debug` and `step` only ever write to stderr.
+| `warn(msg)` | Unless `--quiet` | Something is likely a mistake, but the run goes on. Also added to `status.warnings`. | `Data is piped in, but no flag tells what to do with it` |
+| `error(msg, data)` | Unless `--quiet-total` | Something went wrong. The run goes on, unless `--halt` is set: then a panic is thrown. Also added to `status.errors`, so the CLI gives the exit code 1. | `File not found: a.md` |
+| `die(msg, data, help)` | Unless `--quiet-total` | Something went wrong and the run can not go on. Throws a panic, and the CLI exits with 1. Also added to `status.errors`. | `No data piped into replacement` |
+| `chat(msg)` | `--verbose`, also with `--quiet`, but not with `--quiet-total` | The user: what happens to each file. Only ever to stderr. Also kept in `engine.steps` of the status report. | `Open sync: a.md`, `Nothing changed in: a.md` |
+
+- What the run did is in the status report: the engine resolves with it, and `--status` prints it. So there is no extra debug output to print along the way.
+- `--debug` prints only the status report, with what went into the engine and what it did.
+- `warn()`, `error()` and `die()` add to the status report as they go, also when the quiet flags hide what they print.
 
 ## Tests
 
 - **Tests are strict, lean and focused too.** One thing per test, and the name of the test says what it is.
-- Expect the full result where it matters (`{out, err, exit}`), so nothing extra slips through.
+- Expect the full result where it matters (`{out, err, exit}` from `rr()`), so nothing extra slips through. Use `rrStatus()` for the status of the same run.
 - A known bug is a `test.todo('BUG #<issue>: ...')` until it is fixed. Then it becomes a real test.
 - A test for an issue goes in `test/js/fix/<issue>.test.js`.
 - Use Bun native file IO (`Bun.write`, `Bun.file`) and `Bun.spawnSync` in new tests (#734).

package.json

@@ -43,8 +43,8 @@
 		"test-speed": "bash test/speed/run.sh",
 		"rebase": "yarn is-git-clean && git fetch && git rebase origin/main",
 		"load-options": "# rr -h | rr 'Options:(.+)Examples:' _ -ms | rr '\\n {26,}|\\n\\n *' ' ' | rr \"'\" '`'  | rr '^  (-.+?), (--[^ ]+) *' '`€1` | **`€2`** ' | rr '(^---- . ----).+?(## Good to know)' '€1 + nl + pipe + nl + nl + €2' readme.md -jspT",
-		"test-format": "prettier . --list-different || (echo 'Please correct file formatting using `yarn format` and try again.' && exit 1)",
-		"format": "prettier . --write",
+		"test-format": "biome format || (echo 'Please correct file formatting using `yarn format` and try again.' && exit 1)",
+		"format": "biome format --write",
 		"is-git-clean": "(git diff --quiet --exit-code --cached && git diff --quiet --exit-code) || (echo Please commit or stash changes && exit 1)",
 		"release": "yarn version",
 		"prerelease": "yarn is-git-clean && yarn test && yarn test-minify && yarn load-options",
@@ -60,9 +60,9 @@
 		"sed"
 	],
 	"devDependencies": {
+		"@biomejs/biome": "2.5.15",
 		"@types/node": "24.19.1",
 		"assert": "^2.0.0",
-		"prettier": "3.9.9",
 		"yarn": "1.22.22"
 	},
 	"resolutions": {

src/alias.ts

@@ -1,7 +1,7 @@
 // The `€` and `§` aliases are for the shell, where `$` and `\` are hard to type, so the CLI uses them and not the engine.
 // Globs, file names and piped data never use them, as `€` and `§` can be part of the text.
 export function alias(config) {
-	const swap = (str) => {
+	const swap = str => {
 		if (!str) {
 			return str;
 		}