feat: added Tune scales to Xen, improved documentation re uzu/strudel#1944

packages/xen/tune.mjs

@@ -7,12 +7,16 @@ This program is free software: you can redistribute it and/or modify it under th
 import Tune from './tunejs.js';
 import { register } from '@strudel/core';
 
+// Tune.scale seems to be in ratio format
+// 
+
 export const tune = register('tune', (scale, pat) => {
   const tune = new Tune();
   if (!tune.isValidScale(scale)) {
     throw new Error('not a valid tune.js scale name: "' + scale + '". See http://abbernie.github.io/tune/scales.html');
   }
   tune.loadScale(scale);
+  // if the tonic is a frequency, why are we putting in "1"
   tune.tonicize(1);
   return pat.withHap((hap) => {
     return hap.withValue(() => tune.note(hap.value));

packages/xen/tunejs.js

@@ -78,14 +78,21 @@ Tune.prototype.frequency = function(stepIn, octaveIn) {
 	}
 	
 	// which scale degree (0 - scale length) is our input
+	// 60 % 12 = 0
 	var scaleDegree = stepIn % this.scale.length
 
+	// what's this doing
+	// 0 scaleDegree = 12
+	// seems to simply be for a negative result from above, maybe another way to do it, but ok for now
 	while (scaleDegree < 0) {
 		scaleDegree += this.scale.length
 	}
 	
+	// tonic is currently always 1
+	// so this is 1*scale[scaledegree]
 	var freq = this.tonic*this.scale[scaleDegree]
 	
+	// map it to octave
 	freq = freq*(Math.pow(2,octave))
 	
 	// truncate irrational numbers
@@ -137,10 +144,13 @@ Tune.prototype.MIDI = function(stepIn,octaveIn) {
 }
 
 /* Load a new scale */
+// sets .scale to ratios
 
 Tune.prototype.loadScale = function(scale){
 
 	/* load the scale */
+	let name
+	if (typeof scale === 'string') name = scale;
 	var freqs = isArrayOfNumbers(scale) ? scale : TuningList[scale].frequencies
 	this.scale = []
 	for (var i=0;i<freqs.length-1;i++) {
@@ -148,10 +158,10 @@ Tune.prototype.loadScale = function(scale){
 	}
 
 	/* visualize in console */
-/* 	console.log(" ");
-	console.log("LOADED "+name);
-	console.log(TuningList[name].description);
-	console.log(this.scale); */
+	// console.log(" ");
+	// console.log("LOADED "+name);
+	// console.log(TuningList[name].description);
+	// console.log(this.scale);
 	var vis = [];
 	for (var i=0;i<100;i++) {
 		vis[i] = " ";

packages/xen/xen.mjs

@@ -5,7 +5,7 @@ This program is free software: you can redistribute it and/or modify it under th
 */
 
 import { register, _mod, parseNumeral } from '@strudel/core';
-
+import Tune from './tunejs.js'
 
 // returns a list of frequency ratios for given edo scale
 export function edo(name) {
@@ -30,12 +30,18 @@ const defaultBase = 220;
 
 // Assumes a base of 220. Returns a filtered scale based on 'indices'
 function getXenScale(scale, indices) {
+  let tune = new Tune()
   if (typeof scale === 'string') {
     if (/^[1-9]+[0-9]*edo$/.test(scale)) {
       scale = edo(scale);
     } else if (presets[scale]) {
       scale = presets[scale];
-    } else {
+    } 
+    else if (tune.isValidScale(scale)) {
+      tune.loadScale(scale)
+      scale = tune.scale
+    } 
+    else {
       throw new Error('unknown scale name: "' + scale + '"');
     }
   }
@@ -69,6 +75,7 @@ function xenOffset(xenScale, offset, index = 0) {
  * @param {(string | number[] )} scaleNameOrRatios
  * @tags music_theory
  * @example
+ * // A major tried in 31edo:
  * "0 8 18".xen("31edo").freq().piano()
  * @example
  * // You can also use xen with frequency ratios. 
@@ -78,8 +85,15 @@ function xenOffset(xenScale, offset, index = 0) {
  * Math.pow(2, 8/31),
  * Math.pow(2, 18/31),
  * ]).freq().piano()
+ * @example 
+ * // xen also supports all scale names that 
+ * // tune does:
+ * "0 1 2 3 4 5".xen("hexany15").freq()
+ * // equiv to: 
+ * // "0 1 2 3 4 5".tune("hexany15").mul("220").freq()
  */
 
+// TODO how do you reference another function in jsdoc (tune, above)
 // TODO support tunings defined in './tunejs.js'
 export const xen = register('xen', function (scaleNameOrRatios, pat) {
   return pat.withHap((hap) => {

website/src/pages/learn/xen.mdx

@@ -8,6 +8,8 @@ import { JsDoc } from '../../docs/JsDoc';
 
 # Xenharmonic Functions (experimental)
 
+{/* TODO expand explanation of xenharmony */}
+
 These functions allow the use of scales other than your typical chromatic 12 based ones.
 
 ### tune(scale)
@@ -96,11 +98,4 @@ The `tranh3` tuning has a similar set of notes, with two clashing. You might try
 
 ### xen(scaleOrRatios)
 
-<JsDoc client:idle name="Pattern.xen" h={0} />
-
-{/* <MiniRepl
-  client:idle
-  tune={`
-  "0 8 18".xen("31edo").freq().piano()
-  `}
-/> */}
+<JsDoc client:idle name="Pattern.xen" h={0} />