@echecs/pgn/dist/lexer.js

PGN is a parser that is part of the ECHECS project, designed to interpret the PGN (Portable Game Notation) specification.

/* eslint-disable sort-keys */
import moo from 'moo';
function pickBy(object, predicate) {
    return Object.fromEntries(Object.entries(object).filter(([key, value]) => predicate(value, key)));
}
// eslint-disable-next-line import-x/no-named-as-default-member
const lexer = moo.states({
    main: {
        __: { lineBreaks: true, match: /\s+/ },
        comment_line: { match: /;.*$/, value: (s) => s.slice(1).trim() },
        comment_multiline: {
            lineBreaks: true,
            match: /{[^}]*}/,
            value: (s) => s
                .slice(1, -1)
                .replace(/[\n\t]/g, ' ')
                .trim(),
        },
        escape: /^%.*$/,
        // --- TAG ---
        lbracket: { match: '[', push: 'tag' },
        rbracket: { match: ']', pop: 1 },
        // --- RESULT ---
        result: ['1-0', '0-1', '1/2-1/2', '*'],
        // --- MOVE ---
        // https://regex101.com/r/zwTzNe/1
        san: {
            // @ts-expect-error Mismatching types
            match: /(?:[KQBNPR]?[a-h]?[1-8]?x?[a-h][1-8]|O-O-O|O-O)(?:=[NBRQ])?[+#]?/,
            value: (s) => {
                if (['O-O', 'O-O-O'].includes(s)) {
                    return { castling: true, long: s === 'O-O-O', piece: 'K', to: s };
                }
                const extractor = /(?<piece>[KQBNPR])?(?<from>[a-h]|[1-8]|[a-h][1-8])?(?<capture>x)?(?<to>[a-h][1-8])(?<promotion>=[NBRQ])?(?<indication>[+#])?/;
                const { groups = {} } = s.match(extractor) || {};
                return pickBy({
                    piece: groups.piece || 'P',
                    from: groups.from,
                    capture: Boolean(groups.capture),
                    to: groups.to,
                    promotion: groups.promotion?.slice(1),
                    check: Boolean(groups.indication?.includes('+')),
                    checkmate: Boolean(groups.indication?.includes('#')),
                }, Boolean);
            },
        },
        // @ts-expect-error Mismatching types
        number: { match: /\d+[.]*/, value: (s) => Number(s.replace(/[.]/g, '')) },
        // --- NAG ---
        nag_import: [
            '!',
            '?',
            '!!',
            '??',
            '!?',
            '?!',
            '□',
            '=',
            '∞',
            '⩲',
            '⩱',
            '±',
            '∓',
            '+ −',
            '− +',
            '⨀',
            '○',
            '⟳',
            '↑',
            '→',
            '⯹',
            '⇆',
            '⨁',
        ],
        nag_export: {
            match: /\$25[0-5]|\$2[0-4][0-9]|\$1[0-9][0-9]|\$[1-9][0-9]|\$[0-9]/,
            value: (s) => s.slice(1),
        },
        // --- RAV ---
        lparen: '(',
        rparen: ')',
    },
    tag: {
        __: { lineBreaks: true, match: /\s+/ },
        identifier: /[a-zA-Z0-9_]+/,
        rbracket: { match: ']', pop: 1 },
        value: {
            match: /"[^"]*?"/,
            value: (s) => s.slice(1, -1).trim(),
        },
    },
});
export default lexer;
//# sourceMappingURL=lexer.js.map