add run + test + docs

packages/core/signal.mjs

@@ -114,6 +114,14 @@ const timeToRands = (t, n) => timeToRandsPrime(timeToIntSeed(t), n);
  *
  */
 
+/**
+ * A discrete pattern of numbers from 0 to n-1
+ * @example
+ * run(4).scale('C4 major').note()
+ * // "0 1 2 3".scale('C4 major').note()
+ */
+export const run = (n) => saw.range(0, n).floor().segment(n);
+
 /**
  * A continuous pattern of random numbers, between 0 and 1.
  *