From fe9a91d1e4d9933d21f9aa028851a62f348ebe1e Mon Sep 17 00:00:00 2001
From: alex <alex@slab.org>
Date: Tue, 24 Jun 2025 23:22:42 +0100
Subject: [PATCH] add unjoin, into and chunkinto

---
 packages/core/pattern.mjs                 | 41 ++++++++++++++
 test/__snapshots__/examples.test.mjs.snap | 69 +++++++++++++++++++++++
 2 files changed, 110 insertions(+)

diff --git a/packages/core/pattern.mjs b/packages/core/pattern.mjs
index beefc5971..0ad1f77c9 100644
--- a/packages/core/pattern.mjs
+++ b/packages/core/pattern.mjs
@@ -869,6 +869,47 @@ export class Pattern {
     console.log(drawLine(this));
     return this;
   }
+
+  //////////////////////////////////////////////////////////////////////
+  // methods relating to breaking patterns into subcycles
+
+  // Breaks a pattern into a pattern of patterns, according to the structure of the given binary pattern.
+  unjoin(pieces, func = id) {
+    return pieces.withHap((hap) =>
+      hap.withValue((v) => (v ? func(this.ribbon(hap.whole.begin, hap.whole.duration)) : this)),
+    );
+  }
+
+  /**
+   * Breaks a pattern into pieces according to the structure of a given pattern.
+   * True values in the given pattern cause the corresponding subcycle of the
+   * source pattern to be looped, and for an (optional) given function to be
+   * applied. False values result in the corresponding part of the source pattern
+   * to be played unchanged.
+   * @name into
+   * @memberof Pattern
+   * @example
+   * sound("bd sd ht lt").into("1 0", hurry(2))
+   */
+  into(pieces, func) {
+    return this.unjoin(pieces, func).innerJoin();
+  }
+
+  /**
+   * Like `chunk`, but the function is applied to a looped subcycle of the source pattern.
+   * @name chunkInto
+   * @synonym chunkinto
+   * @memberof Pattern
+   * @example
+   * sound("bd sd ht lt bd - cp lt").chunkInto(4, hurry(2))
+   *   .bank("tr909")
+   */
+  chunkInto(n, func) {
+    return this.into(fastcat(true, ...Array(n - 1).fill(false)).iterback(4), func);
+  }
+  chunkinto(n, func) {
+    return this.chunkInto(n, func);
+  }
 }
 
 //////////////////////////////////////////////////////////////////////
diff --git a/test/__snapshots__/examples.test.mjs.snap b/test/__snapshots__/examples.test.mjs.snap
index f3607cb48..d0a622940 100644
--- a/test/__snapshots__/examples.test.mjs.snap
+++ b/test/__snapshots__/examples.test.mjs.snap
@@ -1889,6 +1889,46 @@ exports[`runs examples > example "chunkBack" example index 0 1`] = `
 ]
 `;
 
+exports[`runs examples > example "chunkInto" example index 0 1`] = `
+[
+  "[ 0/1 → 1/16 | s:bd speed:2 bank:tr909 ]",
+  "[ 1/16 → 1/8 | s:sd speed:2 bank:tr909 ]",
+  "[ 1/8 → 3/16 | s:bd speed:2 bank:tr909 ]",
+  "[ 3/16 → 1/4 | s:sd speed:2 bank:tr909 ]",
+  "[ 1/4 → 3/8 | s:ht bank:tr909 ]",
+  "[ 3/8 → 1/2 | s:lt bank:tr909 ]",
+  "[ 1/2 → 5/8 | s:bd bank:tr909 ]",
+  "[ 3/4 → 7/8 | s:cp bank:tr909 ]",
+  "[ 7/8 → 1/1 | s:lt bank:tr909 ]",
+  "[ 1/1 → 9/8 | s:bd bank:tr909 ]",
+  "[ 9/8 → 5/4 | s:sd bank:tr909 ]",
+  "[ 5/4 → 21/16 | s:ht speed:2 bank:tr909 ]",
+  "[ 21/16 → 11/8 | s:lt speed:2 bank:tr909 ]",
+  "[ 11/8 → 23/16 | s:ht speed:2 bank:tr909 ]",
+  "[ 23/16 → 3/2 | s:lt speed:2 bank:tr909 ]",
+  "[ 3/2 → 13/8 | s:bd bank:tr909 ]",
+  "[ 7/4 → 15/8 | s:cp bank:tr909 ]",
+  "[ 15/8 → 2/1 | s:lt bank:tr909 ]",
+  "[ 2/1 → 17/8 | s:bd bank:tr909 ]",
+  "[ 17/8 → 9/4 | s:sd bank:tr909 ]",
+  "[ 9/4 → 19/8 | s:ht bank:tr909 ]",
+  "[ 19/8 → 5/2 | s:lt bank:tr909 ]",
+  "[ 5/2 → 41/16 | s:bd speed:2 bank:tr909 ]",
+  "[ 21/8 → 43/16 | s:bd speed:2 bank:tr909 ]",
+  "[ 11/4 → 23/8 | s:cp bank:tr909 ]",
+  "[ 23/8 → 3/1 | s:lt bank:tr909 ]",
+  "[ 3/1 → 25/8 | s:bd bank:tr909 ]",
+  "[ 25/8 → 13/4 | s:sd bank:tr909 ]",
+  "[ 13/4 → 27/8 | s:ht bank:tr909 ]",
+  "[ 27/8 → 7/2 | s:lt bank:tr909 ]",
+  "[ 7/2 → 29/8 | s:bd bank:tr909 ]",
+  "[ 15/4 → 61/16 | s:cp speed:2 bank:tr909 ]",
+  "[ 61/16 → 31/8 | s:lt speed:2 bank:tr909 ]",
+  "[ 31/8 → 63/16 | s:cp speed:2 bank:tr909 ]",
+  "[ 63/16 → 4/1 | s:lt speed:2 bank:tr909 ]",
+]
+`;
+
 exports[`runs examples > example "clip" example index 0 1`] = `
 [
   "[ 0/1 → 1/4 | note:c s:piano clip:0.5 ]",
@@ -4391,6 +4431,35 @@ exports[`runs examples > example "inside" example index 0 1`] = `
 ]
 `;
 
+exports[`runs examples > example "into" example index 0 1`] = `
+[
+  "[ 0/1 → 1/8 | s:bd speed:2 ]",
+  "[ 1/8 → 1/4 | s:sd speed:2 ]",
+  "[ 1/4 → 3/8 | s:bd speed:2 ]",
+  "[ 3/8 → 1/2 | s:sd speed:2 ]",
+  "[ 1/2 → 3/4 | s:ht ]",
+  "[ 3/4 → 1/1 | s:lt ]",
+  "[ 1/1 → 9/8 | s:bd speed:2 ]",
+  "[ 9/8 → 5/4 | s:sd speed:2 ]",
+  "[ 5/4 → 11/8 | s:bd speed:2 ]",
+  "[ 11/8 → 3/2 | s:sd speed:2 ]",
+  "[ 3/2 → 7/4 | s:ht ]",
+  "[ 7/4 → 2/1 | s:lt ]",
+  "[ 2/1 → 17/8 | s:bd speed:2 ]",
+  "[ 17/8 → 9/4 | s:sd speed:2 ]",
+  "[ 9/4 → 19/8 | s:bd speed:2 ]",
+  "[ 19/8 → 5/2 | s:sd speed:2 ]",
+  "[ 5/2 → 11/4 | s:ht ]",
+  "[ 11/4 → 3/1 | s:lt ]",
+  "[ 3/1 → 25/8 | s:bd speed:2 ]",
+  "[ 25/8 → 13/4 | s:sd speed:2 ]",
+  "[ 13/4 → 27/8 | s:bd speed:2 ]",
+  "[ 27/8 → 7/2 | s:sd speed:2 ]",
+  "[ 7/2 → 15/4 | s:ht ]",
+  "[ 15/4 → 4/1 | s:lt ]",
+]
+`;
+
 exports[`runs examples > example "invert" example index 0 1`] = `
 [
   "[ 0/1 → 1/8 | s:bd ]",