source: node_modules/prismjs/components/prism-bison.js

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': /%[%?]|[|:;\[\]<>]/
                }
        }
});