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

// https://gn.googlesource.com/gn/+/refs/heads/main/docs/reference.md#grammar

Prism.languages.gn = {
        'comment': {
                pattern: /#.*/,
                greedy: true
        },
        'string-literal': {
                pattern: /(^|[^\\"])"(?:[^\r\n"\\]|\\.)*"/,
                lookbehind: true,
                greedy: true,
                inside: {
                        'interpolation': {
                                pattern: /((?:^|[^\\])(?:\\{2})*)\$(?:\{[\s\S]*?\}|[a-zA-Z_]\w*|0x[a-fA-F0-9]{2})/,
                                lookbehind: true,
                                inside: {
                                        'number': /^\$0x[\s\S]{2}$/,
                                        'variable': /^\$\w+$/,
                                        'interpolation-punctuation': {
                                                pattern: /^\$\{|\}$/,
                                                alias: 'punctuation'
                                        },
                                        'expression': {
                                                pattern: /[\s\S]+/,
                                                inside: null // see below
                                        }
                                }
                        },
                        'string': /[\s\S]+/
                }
        },

        'keyword': /\b(?:else|if)\b/,
        'boolean': /\b(?:false|true)\b/,
        'builtin-function': {
                // a few functions get special highlighting to improve readability
                pattern: /\b(?:assert|defined|foreach|import|pool|print|template|tool|toolchain)(?=\s*\()/i,
                alias: 'keyword'
        },
        'function': /\b[a-z_]\w*(?=\s*\()/i,
        'constant': /\b(?:current_cpu|current_os|current_toolchain|default_toolchain|host_cpu|host_os|root_build_dir|root_gen_dir|root_out_dir|target_cpu|target_gen_dir|target_os|target_out_dir)\b/,

        'number': /-?\b\d+\b/,

        'operator': /[-+!=<>]=?|&&|\|\|/,
        'punctuation': /[(){}[\],.]/
};

Prism.languages.gn['string-literal'].inside['interpolation'].inside['expression'].inside = Prism.languages.gn;

Prism.languages.gni = Prism.languages.gn;