Merge pull request #70 from tidalcycles/more-functions

More randomness, fix `rand`, and add `brand`, `irand` and `choose`

packages/core/signal.mjs

@@ -1,5 +1,5 @@
 import { Hap } from './hap.mjs';
-import { Pattern, fastcat } from './pattern.mjs';
+import { Pattern, fastcat, reify, silence } from './pattern.mjs';
 import Fraction from './fraction.mjs';
 
 export function steady(value) {
@@ -29,33 +29,49 @@ export const square2 = square._toBipolar();
 export const tri = fastcat(isaw, saw);
 export const tri2 = fastcat(isaw2, saw2);
 
-
 // random signals
 
-const xorwise = x => {
-  const a = (x << 13) ^ x
-  const b = (a >> 17) ^ a
-  return (b << 5) ^ b
-}
+const xorwise = (x) => {
+  const a = (x << 13) ^ x;
+  const b = (a >> 17) ^ a;
+  return (b << 5) ^ b;
+};
 
 // stretch 300 cycles over the range of [0,2**29 == 536870912) then apply the xorshift algorithm
-const _frac = x => x - Math.trunc(x);
+const _frac = (x) => x - Math.trunc(x);
 
-const timeToIntSeed = x => xorwise(Math.trunc(_frac(x / 300) * 536870912));
+const timeToIntSeed = (x) => xorwise(Math.trunc(_frac(x / 300) * 536870912));
 
-const intSeedToRand = x => (x % 536870912) / 536870912;
+const intSeedToRand = (x) => (x % 536870912) / 536870912;
 
-const timeToRand = x => intSeedToRand(timeToIntSeed(x));
+const timeToRand = (x) => intSeedToRand(timeToIntSeed(x));
 
 const timeToRandsPrime = (seed, n) => {
   const result = [];
   for (let i = 0; i < n; ++n) {
     result.push(intSeedToRand(seed));
     seed = xorwise(seed);
   }
-  return(result);
-}
+  return result;
+};
+
+const timeToRands = (t, n) => timeToRandsPrime(timeToIntSeed(t), n);
 
-const timeToRands = (t, n) => timeToRandsPrime(timeToIntSeed(t), n)
+export const rand2 = signal(timeToRand);
+export const rand = rand2.fmap(Math.abs);
+
+export const _brandBy = (p) => rand.fmap((x) => x < p);
+export const brandBy = (pPat) => reify(pPat).fmap(_brandBy).innerJoin();
+export const brand = _brandBy(0.5);
+
+export const _irand = (i) => rand.fmap((x) => Math.trunc(x * i));
+export const irand = (ipat) => reify(ipat).fmap(_irand).innerJoin();
+
+export const chooseWith = (pat, xs) => {
+  if (xs.length == 0) {
+    return silence;
+  }
+  return pat.range(0, xs.length).fmap((i) => xs[Math.floor(i)]);
+};
 
-export const rand = signal(timeToRand)
+export const choose = (...xs) => chooseWith(rand, xs);

repl/src/useCycle.mjs

@@ -39,7 +39,7 @@ function useCycle(props) {
 
     // schedule events for next cycle
     events
-      ?.filter((event) => event.part.begin.equals(event.whole.begin))
+      ?.filter((event) => event.part.begin.equals(event.whole?.begin))
       .forEach((event) => {
         Tone.getTransport().schedule((time) => {
           onEvent(time, event, Tone.getContext().currentTime);