RealParser.ts

import { Measure } from './Measure';
import { Measures } from './Sheet';

// extension of https://github.com/daumling/ireal-renderer/blob/master/src/ireal-renderer.js

export class RealParser {
    /**
     * The RegExp for a complete chord. The match array contains:
     * 1 - the base note
     * 2 - the modifiers (+-ohd0123456789 and su for sus)
     * 3 - any comments (may be e.g. add, sub, or private stuff)
     * 4 - the "over" part starting with a slash
     * 5 - the top chord as (chord)
     * @type RegExp
     */

    static chordRegex = /^([ A-GW][b#]?)((?:sus|[\+\-\^\dhob#])*)(\*.+?\*)*(\/[A-G][#b]?)?(\(.*?\))?/;

    static regExps = [
        /^\*[a-zA-Z]/,							// section
        /^T\d\d/,								// time measurement
        /^N./,									// repeat marker
        /^<.*?>/,								// comments
        /^ \(.*?\)/,							// blank and (note)
        RealParser.chordRegex,				// chords
        /^LZ/,									// 1 cell + right bar
        /^XyQ/,									// 3 empty cells
        /^Kcl/									// repeat last bar
    ];

    static replacements = {
        "LZ": [" ", "|"],
        "XyQ": [" ", " ", " "],
        "Kcl": ["|", "x", " "]
    };

    static getChord(iRealChord) {
        return iRealChord.note + iRealChord.modifiers + (iRealChord.over ? '/' + this.getChord(iRealChord.over) : '');
    }

    static parseSheet(raw): Measures {
        const tokens = RealParser.parse(raw);
        return RealParser.getSheet(tokens);
    }

    static getSheet(tokens): Measures {
        const parsed = tokens
            .reduce((current, token, index, array) => {
                const lastBarEnded = ['{', '|', '[', '||' /* 'Z',  *//* , ']' */]
                    .includes(token.bars || token.token);
                let signs = token.annots || [];
                const repeatStart = (token.bars || token.token) === '{';
                const repeatEnd = (token.bars || token.token) === '}';
                if (repeatStart) {
                    signs.push('{');
                }
                if (repeatEnd) {
                    signs.push('}');
                }
                // current.measure ends
                if (lastBarEnded) {
                    if (current.measure) {
                        // simplify measure if no signs
                        /* if (Object.keys(current.measure).find(k=>k)) {
                            current.measure = current.measure.chords;
                        } */
                        current.measures.push(current.measure);
                    }
                    current.measure = { chords: [] };
                }

                const sectionStart = signs.find(a => a.match(/^\*[a-zA-Z]/));
                if (sectionStart) {
                    signs = signs.filter(s => s !== sectionStart);
                    current.measure.section = sectionStart.replace('*', '');
                }

                const hasCodaSign = signs.includes('Q');
                if (hasCodaSign) {
                    signs = signs.filter(s => s !== 'Q');
                    let codaSign = 'ToCoda';
                    if (!!current.measures.find(m => Measure.hasSign('ToCoda', m))) {
                        codaSign = 'Coda';
                    }
                    current.measure.signs = (current.measure.signs || []).concat([codaSign]);
                }

                const houseStart = signs.find(s => !!s.match(/^N./));
                if (houseStart) {
                    signs = signs.filter(s => s !== houseStart);
                    current.measure.house = parseInt(houseStart.replace('N', ''));
                }

                const time = signs.find(a => a.match(/^T\d\d/));
                if (time) {
                    signs = signs.filter(s => s !== time);
                    current.measure.time = time.replace('T', '');
                }

                if (token.chord) {
                    current.measure.chords.push(this.getChord(token.chord));
                } else if (token.token === 'n') {
                    current.measure.chords.push(0);
                }

                const last = current.measures[current.measures.length - 1];
                if (last && last.chords[0] === 'r') {
                    last.chords = current.measures[current.measures.length - 3].chords;
                    current.measure.chords = current.measures[current.measures.length - 2].chords;
                }
                if (last && current.measure.chords[0] === 'x') {
                    current.measure.chords = [].concat(last.chords);
                    current.measure.idle = true;
                }

                if (signs.length) {
                    current.measure.signs = (current.measure.signs || [])
                        .concat(signs);
                }
                if (token.comments.length) {
                    current.measure.comments = (current.measure.comments || [])
                        .concat(token.comments.map(c => c.trim()));
                }
                return current;
            }, { measure: null, signs: null, measures: [] });
        if (parsed.measure.chords.length) {
            parsed.measures.push(parsed.measure);
        }
        return parsed.measures;
    }


    static parse(raw: string): any {
        var text = raw;
        var arr = [], headers = [], comments = [];
        var i;
        text = text.trim();
        // text = text.trimRight();
        while (text) {
            var found = false;
            for (i = 0; i < RealParser.regExps.length; i++) {
                var match = RealParser.regExps[i].exec(text);

                if (match) {
                    found = true;
                    if (match.length <= 2) {
                        const replacement = match[0];
                        var repl = RealParser.replacements[replacement];
                        arr = arr.concat(repl ? repl : [replacement]);
                        text = text.substr(replacement.length);
                    }
                    else { // a chord
                        arr.push(match);
                        text = text.substr(match[0].length);
                    }
                    break;
                }
            }
            if (!found) {
                // ignore the comma separator
                if (text[0] !== ',')
                    arr.push(text[0]);
                text = text.substr(1);
            }
        }
        //		console.log(arr);
        // pass 2: extract prefixes, suffixes, annotations and comments
        var out = [];
        var obj = RealParser.newToken(out);
        for (i = 0; i < arr.length; i++) {
            var token = arr[i];
            if (token instanceof Array) {
                obj.chord = RealParser.parseChord(token);
                token = " ";
            }
            switch (token[0]) {
                case ',': token = null; break; // separator
                case 'S':	// segno
                case 'T':	// time measurement
                case 'Q':	// coda
                case 'N':	// repeat
                case 'U':	// END
                case 's':	// small
                case 'l':	// normal
                case 'f':	// fermata
                case '*': obj.annots.push(token); token = null; break;
                case 'Y': obj.spacer++; token = null; break;
                case 'r':
                case 'x':
                case 'W':
                    obj.chord = new iRealChord(token, "", null, null);
                    break;
                case '<':
                    token = token.substr(1, token.length - 2);
                    token = token.replace(/XyQ/g, "   ");	// weird; needs to be done
                    obj.comments.push(token);
                    token = null; break;
                default:
            }
            if (token) {
                if ("]}Z".indexOf(arr[i + 1]) >= 0)
                    obj.bars += arr[++i];
                if ("{[|".indexOf(token) >= 0) {
                    obj.bars += token; token = null;
                }
            }
            if (token && i < arr.length - 1) {
                obj.token = token;
                obj = RealParser.newToken(out);
            }
        }
        return out;
    }



    static parseChord(match) {
        var note = match[1] || " ";
        var modifiers = match[2] || "";
        var comment = match[3] || "";
        if (comment)
            modifiers += comment.substr(1, comment.length - 2).replace("XyQ", "   ");
        var over = match[4] || "";
        if (over[0] === '/')
            over = over.substr(1);
        var alternate = match[5] || null;
        if (alternate) {
            match = RealParser.chordRegex.exec(alternate.substr(1, alternate.length - 2));
            if (!match)
                alternate = null;
            else
                alternate = this.parseChord(match);
        }
        // empty cell?
        if (note === " " && !alternate && !over)
            return null;
        if (over) {
            var offset = (over[1] === '#' || over[1] === 'b') ? 2 : 1;
            over = new iRealChord(over.substr(0, offset), over.substr(offset), null, null);
        }
        else
            over = null;
        return new iRealChord(note, modifiers, over, alternate);
    }

    static newToken(arr) {
        var obj = new iRealToken;
        arr.push(obj);
        return obj;
    }

}

class iRealChord {
    note: any;
    modifiers: any;
    over: any;
    alternate: any;
    constructor(note, modifiers, over, alternate) {
        this.note = note;
        this.modifiers = modifiers;
        this.over = over;
        this.alternate = alternate;
    }
}

class iRealToken {
    chord: any;
    spacer: number;
    bars: string;
    comments: any[];
    token: any;
    annots: any[];
    constructor() {
        this.annots = [];
        this.comments = [];
        this.bars = "";
        this.spacer = 0;
        this.chord = null;
    }
}