build

docs/_snowpack/link/strudel.js

@@ -1,5 +1,6 @@
 import Fraction from "../pkg/fractionjs.js";
 import {compose} from "../pkg/ramda.js";
+import {isNote, toMidi} from "./util.js";
 const removeUndefineds = (xs) => xs.filter((x) => x != void 0);
 const flatten = (arr) => [].concat(...arr);
 const id = (a) => a;
@@ -327,17 +328,39 @@ class Pattern {
   _opleft(other, func) {
     return this.fmap(func).appLeft(reify(other));
   }
+  _asNumber() {
+    return this._withEvent((event) => {
+      const asNumber = Number(event.value);
+      if (!isNaN(asNumber)) {
+        return event.withValue(() => asNumber);
+      }
+      const specialValue = {
+        e: Math.E,
+        pi: Math.PI
+      }[event.value];
+      if (typeof specialValue !== "undefined") {
+        return event.withValue(() => specialValue);
+      }
+      if (isNote(event.value)) {
+        return new Hap(event.whole, event.part, toMidi(event.value), {...event.context, type: "midi"});
+      }
+      throw new Error('cannot parse as number: "' + event.value + '"');
+    });
+  }
   add(other) {
-    return this._opleft(other, (a) => (b) => a + b);
+    return this._asNumber()._opleft(other, (a) => (b) => a + b);
   }
   sub(other) {
-    return this._opleft(other, (a) => (b) => a - b);
+    return this._asNumber()._opleft(other, (a) => (b) => a - b);
   }
   mul(other) {
-    return this._opleft(other, (a) => (b) => a * b);
+    return this._asNumber()._opleft(other, (a) => (b) => a * b);
   }
   div(other) {
-    return this._opleft(other, (a) => (b) => a / b);
+    return this._asNumber()._opleft(other, (a) => (b) => a / b);
+  }
+  round() {
+    return this._asNumber().fmap((v) => Math.round(v));
   }
   union(other) {
     return this._opleft(other, (a) => (b) => Object.assign({}, a, b));

docs/_snowpack/link/util.js

@@ -0,0 +1,33 @@
+export const isNote = (name) => /^[a-gA-G][#b]*[0-9]$/.test(name);
+export const tokenizeNote = (note) => {
+  if (typeof note !== "string") {
+    return [];
+  }
+  const [pc, acc = "", oct] = note.match(/^([a-gA-G])([#b]*)([0-9])?$/)?.slice(1) || [];
+  if (!pc) {
+    return [];
+  }
+  return [pc, acc, oct ? Number(oct) : void 0];
+};
+export const toMidi = (note) => {
+  const [pc, acc, oct] = tokenizeNote(note);
+  if (!pc) {
+    throw new Error('not a note: "' + note + '"');
+  }
+  const chroma = {c: 0, d: 2, e: 4, f: 5, g: 7, a: 9, b: 11}[pc.toLowerCase()];
+  const offset = acc?.split("").reduce((o, char) => o + {"#": 1, b: -1}[char], 0) || 0;
+  return (Number(oct) + 1) * 12 + chroma + offset;
+};
+export const fromMidi = (n) => {
+  return Math.pow(2, (n - 69) / 12) * 440;
+};
+export const mod = (n, m) => n < 0 ? mod(n + m, m) : n % m;
+export const getPlayableNoteValue = (event) => {
+  let {value: note, context} = event;
+  if (typeof note === "number" && context.type !== "frequency") {
+    note = fromMidi(event.value);
+  } else if (typeof note === "string" && !isNote(note)) {
+    throw new Error("not a note: " + note);
+  }
+  return note;
+};