Add Swift highlighting

.changeset/swift.md

@@ -0,0 +1,5 @@
+---
+"@tanstack/highlight": minor
+---
+
+Add an isolated Swift language definition. Core and existing selective bundles are unchanged.

README.md

@@ -195,7 +195,7 @@ Available themes: Aurora X, Dracula, GitHub Dark, GitHub Light, Gruvbox Dark, Gr
 
 ## Languages
 
-`apache`, `cmake`, `cpp`, `csharp`, `css`, `dart`, `diff`, `dockerfile`, `ejs`, `env`, `go`, `html`, `http`, `java`, `js`, `json`, `jsx`, `kotlin`, `lua`, `markdown`, `mermaid`, `nginx`, `perl`, `php`, `plaintext`, `python`, `ruby`, `rust`, `scheme`, `shell`, `sql`, `svelte`, `toml`, `ts`, `tsrx`, `tsx`, `vue`, and `yaml`.
+`apache`, `cmake`, `cpp`, `csharp`, `css`, `dart`, `diff`, `dockerfile`, `ejs`, `env`, `go`, `html`, `http`, `java`, `js`, `json`, `jsx`, `kotlin`, `lua`, `markdown`, `mermaid`, `nginx`, `perl`, `php`, `plaintext`, `python`, `ruby`, `rust`, `scheme`, `shell`, `sql`, `svelte`, `swift`, `toml`, `ts`, `tsrx`, `tsx`, `vue`, and `yaml`.
 
 Each language is available from `@tanstack/highlight/languages/<name>`. The aggregate `@tanstack/highlight/languages` entry can tree-shake, while direct subpaths make isolation explicit. Importing only core helpers from the root entry also removes unused language registrations in a compatible bundler.
 
@@ -218,7 +218,7 @@ Local browser bundles, minified with esbuild and compressed independently. KB us
 | Core + TSX | 10.11 KB | 4.26 KB | 3.90 KB |
 | Octane MDX + TypeScript | 13.86 KB | 5.59 KB | 5.17 KB |
 | Nine-language docs set | 16.04 KB | 6.20 KB | 5.66 KB |
-| All 38 languages | 49.99 KB | 16.82 KB | 15.19 KB |
+| All 39 languages | 52.74 KB | 17.73 KB | 15.93 KB |
 
 The following comparison was measured before the 1.0 property-context correction. Re-run the comparison commands below for current timings.
 

docs/guides/performance.md

@@ -8,15 +8,15 @@ CI measures selective browser bundles and highlighting performance on real docum
 
 ## Bundle profiles
 
-`pnpm run size` builds twenty-five browser profiles with esbuild and measures minified, gzip, and Brotli bytes independently. It also checks that helper, adapter, and selective language imports retain only the requested modules.
+`pnpm run size` builds twenty-six browser profiles with esbuild and measures minified, gzip, and Brotli bytes independently. It also checks that helper, adapter, and selective language imports retain only the requested modules.
 
 | Profile | Registered languages | Current gzip | CI budget |
 | --- | --- | ---: | ---: |
 | Core | None | 1.82 KB | 2.0 KB |
 | TSX | TSX | 4.26 KB | 4.35 KB |
 | Octane | TypeScript plus Octane MDX adapter | 5.59 KB | 5.7 KB |
 | Docs | CSS, HTML, JS, JSON, JSX, Markdown, Shell, TS, TSX | 6.20 KB | 6.3 KB |
-| All | All 38 definitions | 16.82 KB | 17.1 KB |
+| All | All 39 definitions | 17.73 KB | 18.0 KB |
 
 KB uses 1,000 bytes. Core helpers imported from the root tree-shake to the same engine size. The standalone theme helper is 695 gzip bytes.
 
@@ -26,7 +26,7 @@ Selective profiles are the primary metric. The all-language profile exists to pr
 
 The committed corpus contains 334 real code fences sampled from TanStack documentation, with up to twenty samples per normalized language.
 
-`pnpm run bench` measures tokenization, HTML, Markdown, HAST, line numbers, long decorated blocks, and dedicated C#, C++, CMake, Dart, Java, Kotlin, Lua, Perl, PHP, Ruby, and Rust samples. Each profile reports the median of three samples after two warmup passes, with a 1.2 second CI budget. The main highlighting profile processes at least 10,000 blocks.
+`pnpm run bench` measures tokenization, HTML, Markdown, HAST, line numbers, long decorated blocks, and dedicated C#, C++, CMake, Dart, Java, Kotlin, Lua, Perl, PHP, Ruby, Rust, and Swift samples. Each profile reports the median of three samples after two warmup passes, with a 1.2 second CI budget. The main highlighting profile processes at least 10,000 blocks.
 
 A local before-and-after review used the same minified bundle settings, fixtures, and benchmark harness on macOS arm64 with Node 24.15.0:
 

docs/installation.md

@@ -60,7 +60,7 @@ export const highlighter = createHighlighter({
 })
 ```
 
-The root entry is useful for prototypes, server-only scripts, or sites where the roughly 17 KB gzip all-language build is acceptable:
+The root entry is useful for prototypes, server-only scripts, or sites where the roughly 18 KB gzip all-language build is acceptable:
 
 ```ts
 import { highlight } from '@tanstack/highlight'

docs/language-support.md

@@ -42,6 +42,7 @@ Every language is an isolated definition imported from `@tanstack/highlight/lang
 | Shell | `shell` | `bash`, `sh`, `zsh`, `cmd`, `console` | Heredocs, parameter expansion, comment boundaries |
 | SQL | `sql` | - | Strings, comments, common SQL clauses |
 | Svelte | `svelte` | - | Markup plus optional script/style and expression delegation |
+| Swift | `swift` | - | Interpolated, multi-line, and raw strings with nested quotes, regex literals vs division, nested block comments, contextual keywords, attributes and directives |
 | TOML | `toml` | - | Strings, comments, tables, properties |
 | TypeScript | `ts` | `typescript`, `angular-ts` | JavaScript scanner plus TypeScript keywords/types |
 | TSRX | `tsrx` | `octane` | TypeScript, contextual JSX, Octane component shorthand and template directives |

docs/reference/default-entry.md

@@ -43,7 +43,7 @@ Returns the canonical registered language name for a name or alias. Names are tr
 function listLanguages(): Array<HighlightLanguage>
 ```
 
-Returns the 38 canonical language names registered in `defaultHighlighter`.
+Returns the 39 canonical language names registered in `defaultHighlighter`.
 
 ### `tokenize`
 

docs/reference/languages.md

@@ -53,13 +53,14 @@ const highlighter = createHighlighter({
 | `shell` | `@tanstack/highlight/languages/shell` | `bash`, `sh`, `zsh`, `cmd`, `console` |
 | `sql` | `@tanstack/highlight/languages/sql` | None |
 | `svelte` | `@tanstack/highlight/languages/svelte` | None |
+| `swift` | `@tanstack/highlight/languages/swift` | None |
 | `toml` | `@tanstack/highlight/languages/toml` | None |
 | `ts` | `@tanstack/highlight/languages/ts` | `typescript`, `angular-ts` |
 | `tsrx` | `@tanstack/highlight/languages/tsrx` | `octane` |
 | `tsx` | `@tanstack/highlight/languages/tsx` | None |
 | `vue` | `@tanstack/highlight/languages/vue` | None |
 | `yaml` | `@tanstack/highlight/languages/yaml` | `yml` |
 
-`@tanstack/highlight/languages` re-exports `apache`, `cmake`, `cpp`, `csharp`, `css`, `dart`, `diff`, `dockerfile`, `ejs`, `env`, `go`, `html`, `http`, `java`, `js`, `json`, `jsx`, `kotlin`, `lua`, `markdown`, `mermaid`, `nginx`, `perl`, `php`, `plaintext`, `python`, `ruby`, `rust`, `scheme`, `shell`, `sql`, `svelte`, `toml`, `ts`, `tsrx`, `tsx`, `vue`, and `yaml`. The barrel is convenient but individual subpaths make bundle intent explicit.
+`@tanstack/highlight/languages` re-exports `apache`, `cmake`, `cpp`, `csharp`, `css`, `dart`, `diff`, `dockerfile`, `ejs`, `env`, `go`, `html`, `http`, `java`, `js`, `json`, `jsx`, `kotlin`, `lua`, `markdown`, `mermaid`, `nginx`, `perl`, `php`, `plaintext`, `python`, `ruby`, `rust`, `scheme`, `shell`, `sql`, `svelte`, `swift`, `toml`, `ts`, `tsrx`, `tsx`, `vue`, and `yaml`. The barrel is convenient but individual subpaths make bundle intent explicit.
 
 See the [language support matrix](../language-support) for the context-aware behavior and current scope of each registration.

docs/test-strategy.md

@@ -19,21 +19,21 @@ The suite protects the package's actual product boundary: valid code commonly pu
 
 ## Size Profiles
 
-`pnpm run size` checks twenty-five independent browser profiles, including root helpers, language barrel imports, adapters, and themes. Each has minified, gzip, and Brotli budgets. The main highlighter profiles are:
+`pnpm run size` checks twenty-six independent browser profiles, including root helpers, language barrel imports, adapters, and themes. Each has minified, gzip, and Brotli budgets. The main highlighter profiles are:
 
 | Profile | Languages | Gzip budget |
 | --- | --- | ---: |
 | Core | None | 2.0 KB |
 | TSX | TSX | 4.35 KB |
 | Octane | TypeScript plus Octane MDX adapter | 5.7 KB |
 | Docs | CSS, HTML, JS, JSON, JSX, Markdown, Shell, TS, TSX | 6.3 KB |
-| All | All 38 definitions | 17.1 KB |
+| All | All 39 definitions | 18.0 KB |
 
 The selective profiles are the primary product metric. The all-language profile protects the convenience entry from unbounded growth. Bundle graphs reject unexpected language or theme code. Package tests repeat isolation checks through public exports after building.
 
 ## Throughput
 
-`pnpm run bench` measures highlighting, tokenization, Markdown, HAST, line numbers, long numbered blocks, long decorated blocks, and dedicated C#, C++, CMake, Dart, Java, Kotlin, Lua, Perl, PHP, Ruby, and Rust samples. Timings use the median of three samples after two warmup passes. Each profile has a 1.2 second CI budget; the main highlighting profile processes at least 10,000 blocks.
+`pnpm run bench` measures highlighting, tokenization, Markdown, HAST, line numbers, long numbered blocks, long decorated blocks, and dedicated C#, C++, CMake, Dart, Java, Kotlin, Lua, Perl, PHP, Ruby, Rust, and Swift samples. Timings use the median of three samples after two warmup passes. Each profile has a 1.2 second CI budget; the main highlighting profile processes at least 10,000 blocks.
 
 `pnpm run compare:sugar-high` compares the overlapping JS/TS/JSX/TSX use case. `pnpm run compare:shiki` compares all supported fixtures. These are directional measurements, not claims of equivalent grammar depth.
 

scripts/bench.mjs

@@ -116,6 +116,12 @@ try {
       observe: (result) => result.html.length,
       targetBlocks: 10_000,
     },
+    swift: {
+      fixtures: [{ rawLang: 'swift', code: '@available(iOS 15, *)\nlet greeting = "Hi \\(user.name) \\(dict["key"] ?? "none")"\nlet raw = #"C:\\path "quoted" \\#(name)"#\n/* outer /* nested */ comment */\n#if DEBUG\nlet n = 0x1F + 1_000 + 1.5e3\n#endif' }],
+      run: (fixture) => highlight(fixture.code, { lang: fixture.rawLang }),
+      observe: (result) => result.html.length,
+      targetBlocks: 10_000,
+    },
     tokenize: {
       fixtures,
       run: (fixture) => tokenize(fixture.code, { lang: fixture.rawLang }),

scripts/language-utils.mjs

@@ -34,6 +34,7 @@ export const supportedLanguages = [
   'shell',
   'sql',
   'svelte',
+  'swift',
   'toml',
   'ts',
   'tsrx',

scripts/measure-size.mjs

@@ -170,13 +170,22 @@ const profiles = {
     languages: ['rust'],
     limits: { minified: 6_800, gzip: 3_200, brotli: 2_950 },
   },
+  swift: {
+    source: `
+      import { createHighlighter } from './src/core.ts'
+      import { swift } from './src/languages/swift.ts'
+      globalThis.highlighter = createHighlighter({ languages: [swift] })
+    `,
+    languages: ['swift'],
+    limits: { minified: 7_450, gzip: 3_550, brotli: 3_250 },
+  },
   all: {
     source: `
       import { defaultHighlighter } from './src/index.ts'
       globalThis.highlighter = defaultHighlighter
     `,
     languages: 'all',
-    limits: { minified: 50_400, gzip: 17_100, brotli: 15_500 },
+    limits: { minified: 53_150, gzip: 18_000, brotli: 16_200 },
   },
   reactAdapter: {
     source: `export * from './src/react.ts'`,

skills/configure-selective-highlighting/references/languages.md

@@ -36,6 +36,7 @@ Import only the definitions the application registers.
 | Shell | `shell` | `@tanstack/highlight/languages/shell` | `bash`, `sh`, `zsh`, `cmd`, `console` |
 | SQL | `sql` | `@tanstack/highlight/languages/sql` | - |
 | Svelte | `svelte` | `@tanstack/highlight/languages/svelte` | - |
+| Swift | `swift` | `@tanstack/highlight/languages/swift` | - |
 | TOML | `toml` | `@tanstack/highlight/languages/toml` | - |
 | TypeScript | `ts` | `@tanstack/highlight/languages/ts` | `typescript`, `angular-ts` |
 | TSRX | `tsrx` | `@tanstack/highlight/languages/tsrx` | `octane` |

src/index.ts

@@ -37,6 +37,7 @@ import { scheme } from './languages/scheme.js'
 import { shell } from './languages/shell.js'
 import { sql } from './languages/sql.js'
 import { svelte } from './languages/svelte.js'
+import { swift } from './languages/swift.js'
 import { toml } from './languages/toml.js'
 import { ts } from './languages/ts.js'
 import { tsrx } from './languages/tsrx.js'
@@ -77,6 +78,7 @@ export type HighlightLanguage =
   | 'shell'
   | 'sql'
   | 'svelte'
+  | 'swift'
   | 'toml'
   | 'ts'
   | 'tsrx'
@@ -157,6 +159,7 @@ export const allLanguages = [
   shell,
   sql,
   svelte,
+  swift,
   toml,
   ts,
   tsrx,

src/languages/index.ts

@@ -30,6 +30,7 @@ export { scheme } from './scheme.js'
 export { shell } from './shell.js'
 export { sql } from './sql.js'
 export { svelte } from './svelte.js'
+export { swift } from './swift.js'
 export { toml } from './toml.js'
 export { ts } from './ts.js'
 export { tsrx } from './tsrx.js'

src/languages/swift.ts

@@ -0,0 +1,88 @@
+import { defineLanguage, type TokenRange } from '../core.js'
+import { collectPatternRanges } from '../internal/patterns.js'
+
+const patterns = [
+  { className: 'meta', regex: /^#!.*|#\w+/gm },
+  { className: 'attr', regex: /@\w+/g },
+  { className: 'variable', regex: /\$\w+/g },
+  // Argument and parameter labels; the lookbehind keeps ternaries and switch cases plain.
+  { className: 'property', regex: /\b(?=[a-z]\w*:)(?<=[(,]\s*(?:\w+[ \t]+)?)\w+/g },
+  // Contextual words are keywords only before declarations, types, or as accessors.
+  {
+    className: 'keyword',
+    regex: /(?<!`)\b(?:(?<!\.)(?:associatedtype|as|async|await|break|case|catch|class|continue|convenience|default|defer|deinit|didSet|distributed|do|else|enum|extension|fallthrough|fileprivate|for|func|guard|if|import|in|indirect|inout|internal|is|let|mutating|nonisolated|nonmutating|operator|override|precedencegroup|private|protocol|public|repeat|rethrows|return|static|struct|subscript|switch|throw|throws|try|typealias|unowned|var|where|while|willSet)|init|self|Self|super)\b|(?<![\w.`])(?:(?:open|package|optional|dynamic|final|lazy|weak|required|prefix|infix|postfix|actor|macro|some|any|each|isolated|consuming|borrowing|sending)(?=[ \t]+(?:[a-z]{3}|[A-Z([]))|[gs]et(?=[ \t]*[{}]|[ \t]+[a-z]|\(\w+\)[ \t]*\{)|(?<=\()set(?=\)))/g,
+  },
+  { className: 'literal', regex: /(?<![.`])\b(?:true|false|nil)\b/g },
+  { className: 'type', regex: /\b(?:class|struct|enum|protocol|extension|actor|typealias|associatedtype)\s+(\w+)/g, group: 1 },
+  { className: 'type', regex: /\b[A-Z][A-Z\d_]*[a-z]\w*/g },
+  { className: 'function', regex: /\b(?:func|macro)\s+(\w+)/g, group: 1 },
+  { className: 'function', regex: /\b[a-z_]\w*(?=\()|(?<=^[ \t]*\.)[a-z_]\w*(?=[ \t]*\{)|(?<=\.)[a-z_]\w*(?=[ \t]*\{[ \t]*(?:!?[$[]|[\w, ]+ in\b))/gm },
+  { className: 'number', regex: /(?<!\w|[^.]\.)(?:0[xob][\da-f_]+(?:(?:\.[\da-f_]+)?p[+-]?\d+)?|\d[\d_]*(?:\.\d[\d_]*)?(?:e[+-]?\d[\d_]*)?)(?!\w|\.\d)/gi },
+  { className: 'property', regex: /(?<!\.)\.([A-Za-z_]\w*)/g, group: 1 },
+  { className: 'operator', regex: /\.\.[.<]|[-+*/%&|^~!<>=?]+/g },
+] satisfies Parameters<typeof collectPatternRanges>[1]
+
+// `(?<!#)` keeps runs of `#` from being retried at every position.
+const quote = /(?<!#)(#*)("(?:"")?)/y
+
+export const swift = defineLanguage({
+  name: 'swift',
+  tokenize(code) {
+    const ranges: Array<TokenRange> = []
+    // Comments; string openers (closed by stringEnd); `#/…/#` regexes, multi-line only when `#/` ends
+    // the line and running to the line (or input) end when unterminated so retries stay linear;
+    // bare `/re/` only where an operand is expected, never across lines.
+    const lexical = /(\/\/.*|\/\*)|(?<!#)(?:(#*")|(#+)\/(?:\n[^]*?(?:\/\3|(?![^]))|.*?(?:\/\3|$)))|\/(?<=(?:[=(,:[{]|\b(?:return|case))[ \t]*\/)(?![\s/*])(?:\\.|[^\\\n/])+(?<!\s)\//gm
+    let match: RegExpExecArray | null
+    while ((match = lexical.exec(code))) {
+      const comment = match[1]
+      let end = lexical.lastIndex
+      if (comment === '/*') {
+        for (let depth = 1; depth && end < code.length;) {
+          const step = code.startsWith('/*', end) ? 1 : code.startsWith('*/', end) ? -1 : 0
+          depth += step
+          end += step ? 2 : 1
+        }
+      } else if (match[2]) end = stringEnd(code, match.index)
+      ranges.push({ start: match.index, end, className: comment ? 'comment' : 'string' })
+      lexical.lastIndex = end
+    }
+    return collectPatternRanges(code, patterns, ranges)
+  },
+})
+
+// Each frame is the text that closes it: an open string's delimiter, or the `)`s that still close
+// a `\( )` hole, so quotes and parens inside holes nest.
+function stringEnd(code: string, index: number) {
+  const stack: Array<string> = []
+  let open: RegExpExecArray | null
+  do {
+    const top = stack.at(-1) ?? ')'
+    const hole = top[0] === ')'
+    const char = code[index]
+    quote.lastIndex = index
+    if (hole && (open = quote.exec(code))) {
+      stack.push(open[2] + open[1])
+      index = quote.lastIndex
+    } else if (char === '\n' && !(hole ? stack.at(-2)! : top).startsWith('"""')) {
+      // A line break ends every single-line string, and the holes inside it, down to the nearest `"""`.
+      while (stack.length && !stack.at(-1)!.startsWith('"""')) stack.pop()
+      if (stack.length) index++
+    } else if (hole) {
+      if (char === '(') stack.push(stack.pop() + ')')
+      else if (char === ')' && stack.pop()!.length > 1) stack.push(top.slice(1))
+      index++
+    } else if (code.startsWith(top, index)) {
+      stack.pop()
+      index += top.length
+    } else {
+      const hashes = top.replace(/"+/, '')
+      if (char === '\\' && code.startsWith(hashes, index + 1)) {
+        index += hashes.length + 1
+        if (code[index] === '(') stack.push(')')
+        if (code[index] !== '\n') index++
+      } else index++
+    }
+  } while (stack.length && index < code.length)
+  return Math.min(index, code.length)
+}

test/fixtures.ts

@@ -74,6 +74,12 @@ export const languageFixtures: Array<LanguageFixture> = [
     code: 'use std::fmt;\n#[derive(Debug)]\nstruct Point { x: i32 }\nfn main() {\n    let count = 42; // total\n    println!("Hello {}", count);\n}',
     expectedClasses: ['th-keyword', 'th-type', 'th-function', 'th-number', 'th-operator', 'th-comment', 'th-string'],
   },
+  {
+    lang: 'swift',
+    normalized: 'swift',
+    code: 'import Foundation\n@MainActor\nfunc greet(name: String) -> String {\n    let count = 42 // total\n    return "Hello \\(name)"\n}',
+    expectedClasses: ['th-keyword', 'th-type', 'th-attr', 'th-function', 'th-number', 'th-operator', 'th-comment', 'th-string'],
+  },
   {
     lang: 'octane',
     normalized: 'tsrx',

test/real-doc-fixtures.test.ts

@@ -11,7 +11,7 @@ type DocFixture = {
 }
 
 const fixtures = fixtureData.fixtures as Array<DocFixture>
-const languagesWithoutRealDocFixtures = new Set(['go', 'cpp', 'cmake', 'php', 'csharp', 'dart', 'java', 'kotlin', 'lua', 'perl', 'ruby', 'rust'])
+const languagesWithoutRealDocFixtures = new Set(['go', 'cpp', 'cmake', 'php', 'csharp', 'dart', 'java', 'kotlin', 'lua', 'perl', 'ruby', 'rust', 'swift'])
 
 describe('real TanStack docs fixtures', () => {
   it('covers normalized language targets available in TanStack docs', () => {