# json_sm URL: /api/lexers/json_sm/ Section: lexers -------------------------------------------------------------------------------- json_sm - Rosettes window.BENGAL_THEME_DEFAULTS = { appearance: 'light', palette: 'brown-bengal' }; window.Bengal = window.Bengal || {}; window.Bengal.enhanceBaseUrl = '/rosettes/assets/js/enhancements'; window.Bengal.watchDom = true; window.Bengal.debug = false; window.Bengal.enhanceUrls = { 'toc': '/rosettes/assets/js/enhancements/toc.632a9783.js', 'docs-nav': '/rosettes/assets/js/enhancements/docs-nav.57e4b129.js', 'tabs': '/rosettes/assets/js/enhancements/tabs.aac9e817.js', 'lightbox': '/rosettes/assets/js/enhancements/lightbox.1ca22aa1.js', 'interactive': '/rosettes/assets/js/enhancements/interactive.fc077855.js', 'mobile-nav': '/rosettes/assets/js/enhancements/mobile-nav.d991657f.js', 'action-bar': '/rosettes/assets/js/enhancements/action-bar.d62417f4.js', 'copy-link': '/rosettes/assets/js/enhancements/copy-link.7d9a5c29.js', 'data-table': '/rosettes/assets/js/enhancements/data-table.1f5bc1eb.js', 'lazy-loaders': '/rosettes/assets/js/enhancements/lazy-loaders.a5c38245.js', 'holo': '/rosettes/assets/js/enhancements/holo.ee13c841.js', 'link-previews': '/rosettes/assets/js/enhancements/link-previews.8d906535.js' }; (function () { try { var defaults = window.BENGAL_THEME_DEFAULTS || { appearance: 'system', palette: '' }; var defaultAppearance = defaults.appearance; if (defaultAppearance === 'system') { defaultAppearance = (window.matchMedia && window.matchMedia('(prefers-color-scheme: dark)').matches) ? 'dark' : 'light'; } var storedTheme = localStorage.getItem('bengal-theme'); var storedPalette = localStorage.getItem('bengal-palette'); var theme = storedTheme ? (storedTheme === 'system' ? defaultAppearance : storedTheme) : defaultAppearance; var palette = storedPalette ?? defaults.palette; document.documentElement.setAttribute('data-theme', theme); if (palette) { document.documentElement.setAttribute('data-palette', palette); } } catch (e) { document.documentElement.setAttribute('data-theme', 'light'); } })(); { "prerender": [ { "where": { "and": [ { "href_matches": "/docs/*" }, { "not": { "selector_matches": "[data-external], [target=_blank], .external" } } ] }, "eagerness": "conservative" } ], "prefetch": [ { "where": { "and": [ { "href_matches": "/*" }, { "not": { "selector_matches": "[data-external], [target=_blank], .external" } } ] }, "eagerness": "conservative" } ] } Skip to main content Magnifying Glass ESC Recent Clear Magnifying Glass No results for "" Start typing to search... ↑↓ Navigate ↵ Open ESC Close Powered by Lunr ⌾⌾⌾ DocumentationInfoAboutArrow ClockwiseGet StartedCodeHighlightingPaletteStylingStarburstExtendingFormattersNoteTutorialsBookmarkReferenceReleasesDevGitHubAPI Reference Magnifying Glass Search ⌘K Palette Appearance Chevron Down Mode Monitor System Sun Light Moon Dark Palette Snow Lynx Brown Bengal Silver Bengal Charcoal Bengal Blue Bengal List ⌾⌾⌾ Magnifying Glass Search X Close Documentation Caret Down Info About Arrow Clockwise Get Started Code Highlighting Palette Styling Starburst Extending Formatters Note Tutorials Bookmark Reference Releases Dev Caret Down GitHub API Reference Palette Appearance Chevron Down Mode Monitor System Sun Light Moon Dark Palette Snow Lynx Brown Bengal Silver Bengal Charcoal Bengal Blue Bengal Rosettes API Reference Caret Right Formatters html null terminal Caret Right Lexers _scanners _state_machine bash_sm c_sm clojure_sm cpp_sm css_sm csv_sm cuda_sm cue_sm dart_sm diff_sm dockerfile_sm elixir_sm gleam_sm go_sm graphql_sm groovy_sm haskell_sm hcl_sm html_sm ini_sm java_sm javascript_sm jinja_sm json_sm julia_sm kida_sm kotlin_sm lua_sm makefile_sm markdown_sm mojo_sm nginx_sm nim_sm perl_sm php_sm pkl_sm plaintext_sm powershell_sm protobuf_sm python_sm r_sm ruby_sm rust_sm scala_sm sql_sm stan_sm swift_sm toml_sm tree_sm triton_sm typescript_sm v_sm xml_sm yaml_sm zig_sm Caret Right Themes _mapping _palette _roles palettes _config _escape _formatter_registry _parallel _protocol _registry _types delegate rosettes Rosettes API ReferenceLexers ᗢ Caret Down Link Copy URL External Open LLM text Copy Copy LLM text Share with AI Ask Claude Ask ChatGPT Ask Gemini Ask Copilot Module lexers.json_sm Hand-written JSON lexer optimized for speed. O(n) guaranteed, zero regex, thread-safe. Design Philosophy: JSON has a minimal grammar (7 token types), so this lexer is optimized for raw speed rather than code reuse. All scanning is inlined to minimize function call overhead. Language Support: Standard JSON (RFC 8259) Strings with escape sequences Numbers (integers and floats with exponents) Literals: true, false, null Arrays and objects Performance: ~25µs per 100-line file — fastest lexer in Rosettes due to JSON's simple grammar. No mixin overhead, all hot paths inlined. Token Types Used: STRING: "string values" NUMBER: 123, 3.14, 1e10 KEYWORD_CONSTANT: true, false, null PUNCTUATION: [ ] { } : , WHITESPACE: spaces, tabs, newlines ERROR: invalid characters Thread-Safety: Uses only local variables in tokenize(). No class-level mutable state. See Also: rosettes.lexers.yaml_sm: YAML lexer (superset of JSON) rosettes.lexers.toml_sm: TOML lexer (similar config format) 1Class Classes JsonStateMachineLexer 1 ▼ JSON lexer optimized for minimal overhead. JSON has a simple grammar — this lexer optimizes for ra… JSON lexer optimized for minimal overhead. JSON has a simple grammar — this lexer optimizes for raw speed with all scanning inlined (no mixin overhead). Methods tokenize 2 Iterator[Token] ▼ def tokenize(self, code: str, config: LexerConfig | None = None) -> Iterator[Token] Parameters Name Type Description code — config — Default: None Returns Iterator[Token] ← Previous jinja_sm Next → julia_sm List © 2026 Rosettes built in ᓚᘏᗢ { "linkPreviews": { "enabled": true, "hoverDelay": 200, "hideDelay": 150, "showSection": true, "showReadingTime": true, "showWordCount": true, "showDate": true, "showTags": true, "maxTags": 3, "includeSelectors": [".prose"], "excludeSelectors": ["nav", ".toc", ".breadcrumb", ".pagination", ".card", "[class*='-card']", ".tab-nav", "[class*='-widget']", ".child-items", ".content-tiles"], "allowedHosts": [], "allowedSchemes": ["https"], "hostFailureThreshold": 3 } } window.BENGAL_LAZY_ASSETS = { tabulator: '/rosettes/assets/js/tabulator.min.js', dataTable: '/rosettes/assets/js/data-table.js', mermaidToolbar: '/rosettes/assets/js/mermaid-toolbar.9de5abba.js', mermaidTheme: '/rosettes/assets/js/mermaid-theme.344822c5.js', graphMinimap: '/rosettes/assets/js/graph-minimap.ff04e939.js', graphContextual: '/rosettes/assets/js/graph-contextual.355458ba.js' }; window.BENGAL_ICONS = { close: '/rosettes/assets/icons/close.911d4fe1.svg', enlarge: '/rosettes/assets/icons/enlarge.652035e5.svg', copy: '/rosettes/assets/icons/copy.3d56e945.svg', 'download-svg': '/rosettes/assets/icons/download.04f07e1b.svg', 'download-png': '/rosettes/assets/icons/image.c34dfd40.svg', 'zoom-in': '/rosettes/assets/icons/zoom-in.237b4a83.svg', 'zoom-out': '/rosettes/assets/icons/zoom-out.38857c77.svg', reset: '/rosettes/assets/icons/reset.d26dba29.svg' }; Arrow Up -------------------------------------------------------------------------------- Metadata: - Word Count: 726 - Reading Time: 4 minutes