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use context for scale

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This commit is contained in:
Felix Roos 2022-02-25 20:31:08 +01:00
parent f1362b1c94
commit a3971f793c
1 changed files with 11 additions and 34 deletions
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45
repl/src/tonal.ts
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@ -3,21 +3,6 @@ import { Pattern as _Pattern } from '../../strudel.mjs';
const Pattern = _Pattern as any;
export declare interface NoteEvent {
value: string | number;
scale?: string;
}
function toNoteEvent(event: string | NoteEvent): NoteEvent {
if (typeof event === 'string' || typeof event === 'number') {
return { value: event };
}
if (event.value) {
return event;
}
throw new Error('not a valid note event: ' + JSON.stringify(event));
}
// modulo that works with negative numbers e.g. mod(-1, 3) = 2
const mod = (n: number, m: number): number => (n < 0 ? mod(n + m, m) : n % m);
@ -60,24 +45,16 @@ function scaleTranspose(scale: string, offset: number, note: string) {
return n + o;
}
Pattern.prototype._mapNotes = function (func: (note: NoteEvent) => NoteEvent) {
return this.fmap((event: string | NoteEvent) => {
const noteEvent = toNoteEvent(event);
// TODO: generalize? this is practical for any event that is expected to be an object with
return { ...noteEvent, ...func(noteEvent) };
});
};
Pattern.prototype._transpose = function (intervalOrSemitones: string | number) {
return this._mapNotes(({ value, scale }: NoteEvent) => {
return this._withEvent((event) => {
const interval = !isNaN(Number(intervalOrSemitones))
? Interval.fromSemitones(intervalOrSemitones as number)
: String(intervalOrSemitones);
if (typeof value === 'number') {
if (typeof event.value === 'number') {
const semitones = typeof interval === 'string' ? Interval.semitones(interval) || 0 : interval;
return { value: value + semitones };
return event.withValue(event.value + semitones);
}
return { value: Note.transpose(value, interval), scale };
return event.withValue((v) => Note.transpose(event.value, interval));
});
};
@ -88,26 +65,26 @@ Pattern.prototype._transpose = function (intervalOrSemitones: string | number) {
// or even `stack(c3).superimpose(transpose.slowcat(7, 5))` or
Pattern.prototype._scaleTranspose = function (offset: number | string) {
return this._mapNotes(({ value, scale }: NoteEvent) => {
if (!scale) {
return this._withEvent((event) => {
if (!event.context.scale) {
throw new Error('can only use scaleTranspose after .scale');
}
if (typeof value !== 'string') {
if (typeof event.value !== 'string') {
throw new Error('can only use scaleTranspose with notes');
}
return { value: scaleTranspose(scale, Number(offset), value), scale };
return event.withValue(() => scaleTranspose(event.context.scale, Number(offset), event.value));
});
};
Pattern.prototype._scale = function (scale: string) {
return this._mapNotes((value) => {
let note = value.value;
return this._withEvent((event) => {
let note = event.value;
const asNumber = Number(note);
if (!isNaN(asNumber)) {
let [tonic, scaleName] = Scale.tokenize(scale);
const { pc, oct = 3 } = Note.get(tonic);
note = scaleTranspose(pc + ' ' + scaleName, asNumber, pc + oct);
}
return { ...value, value: note, scale };
return event.withValue(() => note).setContext({ ...event.context, scale });
});
};