Function detectLanguage

src/extraction/grammars.ts:477–497

(filePath: string, source?: string, overrides?: Record<string, Language>)

 * `EXTENSION_MAP`. Omitting it is byte-identical to the zero-config behavior.
 */
export function detectLanguage(filePath: string, source?: string, overrides?: Record<string, Language>): Language {
  // Play `conf/routes` has no grammar — route through the no-symbol path; the
  // Play framework resolver extracts route nodes from it.
  if (isPlayRoutesFile(filePath)) return 'yaml';
  const ext = filePath.substring(filePath.lastIndexOf('.')).toLowerCase();
  // Shopify OS 2.0 JSON templates / section groups → the Liquid extractor (it
  // links each section `"type"` to its `sections/<type>.liquid`).
  if (isShopifyLiquidJson(filePath)) return 'liquid';
  // OTP `.app`/`.app.src` resource files — Erlang terms the grammar parses as
  // top-level expressions (last-dot ext `.src` is too generic for the map).
  if (isErlangAppFile(filePath)) return 'erlang';
  const lang = (overrides && overrides[ext]) || EXTENSION_MAP[ext] || 'unknown';

  // .h files could be C, C++, or Objective-C — check source content
  if (lang === 'c' && ext === '.h' && source) {
    if (looksLikeCpp(source)) return 'cpp';
    if (looksLikeObjc(source)) return 'objc';
  }

  return lang;
}

/**
 * Heuristic: does a .h file contain C++ constructs?