Prism.languages.bison = Prism.languages.extend('c', {});

Prism.languages.insertBefore('bison', 'comment', {
  bison: {
    // This should match all the beginning of the file
    // including the prologue(s), the bison declarations and
    // the grammar rules.
    pattern: /^(?:[^%]|%(?!%))*%%[\s\S]*?%%/,
    inside: {
      c: {
        // Allow for one level of nested braces
        pattern: /%\{[\s\S]*?%\}|\{(?:\{[^}]*\}|[^{}])*\}/,
        inside: {
          delimiter: {
            pattern: /^%?\{|%?\}$/,
            alias: 'punctuation',
          },
          'bison-variable': {
            pattern: /[$@](?:<[^\s>]+>)?[\w$]+/,
            alias: 'variable',
            inside: {
              punctuation: /<|>/,
            },
          },
          rest: Prism.languages.c,
        },
      },
      comment: Prism.languages.c.comment,
      string: Prism.languages.c.string,
      property: /\S+(?=:)/,
      keyword: /%\w+/,
      number: {
        pattern: /(^|[^@])\b(?:0x[\da-f]+|\d+)/i,
        lookbehind: true,
      },
      punctuation: /%[%?]|[|:;\[\]<>]/,
    },
  },
});