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parser.js
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parser.js
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var frequencies = [];
/* function preParseMML(mml) {
for (let i = 0; i < mml.length)
} */
function parseMML(mml) {
mml = preParseMML(mml);
let octave = 4;
for (let i = 0; i < mml.length; i++) {
console.log(mml[i]);
let note = null;
let noteLength = "";
if (mml[i] == "<") { // check if character is octave increase operand
if (octave != 8)
octave++;
} else if (mml[i] == ">") { // check if character is octave decrease operand
if (octave != 0)
octave--;
} else if (mml[i] == "@") {
if (i < mml.length - 1) {
let octaveNum = parseInt(mml[i + 1]);
if (octaveNum != undefined && octaveNum != null && octaveNum != Number.NaN) { // did parseInt actually get a number?
if (octaveNum <= 8 && octaveNum >= 1) { // change lower limit to 0 if users wish for pedal tones.
octave = octaveNum;
} else {
throw new RangeError("Octave can only be from 1 through 8.");
}
} else {
throw new SyntaxError("Invalid syntax at position " + i + ". Unexpected or incomplete symbol '@'");
}
}
++i;
continue;
} else if ((/[a-gA-G]/).test(mml[i].toString())) { // check if character is a character in the range of a through g, case-insensitive.
note = mml[i];
if (i + 1 < mml.length) {
if ((mml[i + 1] == "#" || mml[i + 1] == "+") || mml[i + 1] == "-") { // check if a modifier exists afterwards;
note = note + mml[i + 1];
++i;
if (i + 1 < mml.length) {
while ((i + 1 < mml.length) && (/[0-9]/).test(mml[i + 1])) {
noteLength = mml[i + 1];
++i;
}
if (noteLength == "") {
noteLength = "4";
}
if (!(
noteLength == "1" ||
noteLength == "2" ||
noteLength == "4" ||
noteLength == "8" ||
noteLength == "16" ||
noteLength == "32" ||
noteLength == "64" ||
noteLength == "128" ||
noteLength == "256" ||
noteLength == "512")) {
throw new ArgumentError("Note length must be between 1-512, and must also be a multiple of two, with the exception of 1");
}
}
}
}
} else {
throw new SyntaxError("Invalid syntax at position " + i + ". Expected a musical note name or octave operand");
}
console.log(note);
if (note != null)
frequencies[frequencies.length] = Note.getNoteFrequency(note, octave);
}
console.log(frequencies);
return frequencies;
}