feat: Nix support

README.md

@@ -457,6 +457,7 @@ The `.codegraph/config.json` file controls indexing:
 | Vue | `.vue` | Full support (script + script-setup extraction, Nuxt page/API/middleware routes) |
 | Liquid | `.liquid` | Full support |
 | Pascal / Delphi | `.pas`, `.dpr`, `.dpk`, `.lpr` | Full support (classes, records, interfaces, enums, DFM/FMX form files) |
+| Nix | `.nix` | Full support |
 
 ## Troubleshooting
 

__tests__/extraction.test.ts

@@ -94,6 +94,10 @@ describe('Language Detection', () => {
     expect(detectLanguage('main.dart')).toBe('dart');
   });
 
+  it('should detect Nix files', () => {
+    expect(detectLanguage('default.nix')).toBe('nix');
+  });
+
   it('should return unknown for unsupported extensions', () => {
     expect(detectLanguage('styles.css')).toBe('unknown');
     expect(detectLanguage('data.json')).toBe('unknown');
@@ -105,6 +109,7 @@ describe('Language Support', () => {
     expect(isLanguageSupported('typescript')).toBe(true);
     expect(isLanguageSupported('python')).toBe(true);
     expect(isLanguageSupported('go')).toBe(true);
+    expect(isLanguageSupported('nix')).toBe(true);
     expect(isLanguageSupported('unknown')).toBe(false);
   });
 
@@ -122,6 +127,28 @@ describe('Language Support', () => {
     expect(languages).toContain('swift');
     expect(languages).toContain('kotlin');
     expect(languages).toContain('dart');
+    expect(languages).toContain('nix');
+  });
+});
+
+describe('Nix Extraction', () => {
+  it('should extract Nix bindings and imports', () => {
+    const code = `{
+      hello = "world";
+      package = import ./default.nix;
+    }`;
+
+    const result = extractFromSource('default.nix', code);
+    const hello = result.nodes.find((n) => n.kind === 'variable' && n.name === 'hello');
+    const packageNode = result.nodes.find((n) => n.kind === 'variable' && n.name === 'package');
+    const importNode = result.nodes.find((n) => n.kind === 'import');
+
+    expect(hello).toBeDefined();
+    expect(packageNode).toBeDefined();
+    expect(importNode).toMatchObject({
+      kind: 'import',
+      name: './default.nix',
+    });
   });
 });
 

src/extraction/grammars.ts

@@ -33,6 +33,7 @@ const WASM_GRAMMAR_FILES: Record<GrammarLanguage, string> = {
   swift: 'tree-sitter-swift.wasm',
   kotlin: 'tree-sitter-kotlin.wasm',
   dart: 'tree-sitter-dart.wasm',
+  nix: 'tree-sitter-nix.wasm',
   pascal: 'tree-sitter-pascal.wasm',
   scala: 'tree-sitter-scala.wasm',
 };
@@ -67,6 +68,7 @@ export const EXTENSION_MAP: Record<string, Language> = {
   '.kt': 'kotlin',
   '.kts': 'kotlin',
   '.dart': 'dart',
+  '.nix': 'nix',
   '.liquid': 'liquid',
   '.svelte': 'svelte',
   '.vue': 'vue',
@@ -125,8 +127,8 @@ export async function loadGrammarsForLanguages(languages: Language[]): Promise<v
   for (const lang of toLoad) {
     const wasmFile = WASM_GRAMMAR_FILES[lang];
     try {
-      // Pascal and Scala ship their own WASMs (not in tree-sitter-wasms)
-      const wasmPath = (lang === 'pascal' || lang === 'scala')
+      // Pascal, Scala, and Nix ship their own WASMs (not in tree-sitter-wasms)
+      const wasmPath = (lang === 'pascal' || lang === 'scala' || lang === 'nix')
         ? path.join(__dirname, 'wasm', wasmFile)
         : require.resolve(`tree-sitter-wasms/out/${wasmFile}`);
       const language = await WasmLanguage.load(wasmPath);
@@ -286,6 +288,7 @@ export function getLanguageDisplayName(language: Language): string {
     swift: 'Swift',
     kotlin: 'Kotlin',
     dart: 'Dart',
+    nix: 'Nix',
     svelte: 'Svelte',
     vue: 'Vue',
     liquid: 'Liquid',

src/extraction/languages/index.ts

@@ -23,6 +23,7 @@ import { kotlinExtractor } from './kotlin';
 import { dartExtractor } from './dart';
 import { pascalExtractor } from './pascal';
 import { scalaExtractor } from './scala';
+import { nixExtractor } from './nix';
 
 export const EXTRACTORS: Partial<Record<Language, LanguageExtractor>> = {
   typescript: typescriptExtractor,
@@ -41,6 +42,7 @@ export const EXTRACTORS: Partial<Record<Language, LanguageExtractor>> = {
   swift: swiftExtractor,
   kotlin: kotlinExtractor,
   dart: dartExtractor,
+  nix: nixExtractor,
   pascal: pascalExtractor,
   scala: scalaExtractor,
 };

src/extraction/languages/nix.ts

@@ -0,0 +1,51 @@
+import { getNodeText, getChildByField } from '../tree-sitter-helpers';
+import type { Node as SyntaxNode } from 'web-tree-sitter';
+import type { LanguageExtractor, ImportInfo } from '../tree-sitter-types';
+
+export const nixExtractor: LanguageExtractor = {
+  functionTypes: [],
+  classTypes: [],
+  methodTypes: [],
+  interfaceTypes: [],
+  structTypes: [],
+  enumTypes: [],
+  typeAliasTypes: [],
+  importTypes: ['apply_expression'],
+  callTypes: [],
+  variableTypes: ['binding'],
+  nameField: 'name',
+  bodyField: 'body',
+  paramsField: 'arguments',
+
+  visitNode: (node: SyntaxNode, ctx) => {
+    if (node.type !== 'binding') return false;
+
+    const attrpath = getChildByField(node, 'attrpath');
+    const name = attrpath ? getNodeText(attrpath, ctx.source) : getNodeText(node, ctx.source);
+    const valueNode = getChildByField(node, 'expression');
+    const signature = valueNode ? getNodeText(valueNode, ctx.source) : undefined;
+
+    ctx.createNode('variable', name, node, { signature });
+
+    if (valueNode) {
+      ctx.visitNode(valueNode);
+    }
+
+    return true;
+  },
+
+  extractImport: (node: SyntaxNode, source: string) => {
+    if (node.type !== 'apply_expression') return null;
+    const functionNode = getChildByField(node, 'function');
+    if (!functionNode || getNodeText(functionNode, source) !== 'import') return null;
+
+    const argument = getChildByField(node, 'argument');
+    if (!argument) return null;
+
+    const moduleName = getNodeText(argument, source).replace(/^['"]|['"]$/g, '');
+    return {
+      moduleName,
+      signature: getNodeText(node, source).trim(),
+    } as ImportInfo;
+  },
+};

src/types.ts

@@ -80,11 +80,13 @@ export const LANGUAGES = [
   'swift',
   'kotlin',
   'dart',
+  'nix',
   'svelte',
   'vue',
   'liquid',
   'pascal',
   'scala',
+  'nix',
   'unknown',
 ] as const;
 
@@ -529,6 +531,8 @@ export const DEFAULT_CONFIG: CodeGraphConfig = {
     '**/*.kts',
     // Dart
     '**/*.dart',
+    // Nix
+    '**/*.nix',
     // Svelte
     '**/*.svelte',
     // Vue