From 8e1fba04363cdcf39c946c8fb10a21554ef42cb7 Mon Sep 17 00:00:00 2001
From: alex <alex@slab.org>
Date: Fri, 12 Dec 2025 15:45:36 +0000
Subject: [PATCH] rename delta to loose, add inverse tight, and exponential
 tightx

---
 packages/core/signal.mjs            | 41 ++++++++++++++++++++++++++---
 packages/core/test/pattern.test.mjs | 14 ----------
 2 files changed, 38 insertions(+), 17 deletions(-)

diff --git a/packages/core/signal.mjs b/packages/core/signal.mjs
index 9ac76895..ff94c3b8 100644
--- a/packages/core/signal.mjs
+++ b/packages/core/signal.mjs
@@ -884,10 +884,45 @@ export const keyDown = register('keyDown', function (pat) {
 });
 
 /**
- * A pattern that gives the duration of events that are combined with it.
+ * A pattern giving the 'looseness' of events, or in other words, the duration of pattern events,
+ * in cycles per event. `loose` doesn't have structure itself, but takes structure, and therefore
+ * event durations, from the pattern that it is combined with.
+ * For example `loose.struct("1 1 [1 1] 1")` would give the same as `"0.25 0.25 [0.125 0.125] 0.25"`.
+ * See also its inverse, `tight`.
  * @example
- * sound("bd sd [bd bd] sd*4 [- sd] [bd [bd bd]]").note(delta.withValue(x => 1/x + 20))
+ * // Shorter events are lower in pitch
+ * sound("saw saw [saw saw] saw")
+ *   .note(loose.range(50, 100))
+ * @example
+ * sound("bd sd [bd bd] sd*4 [- sd] [bd [bd bd]]")
+ *   .note(tight.add(20))
  */
-export const delta = new Pattern(function (state) {
+export const loose = new Pattern(function (state) {
   return [new Hap(undefined, state.span, state.span.duration)];
 });
+
+/**
+ * A pattern giving the 'tightness' of events, or in other words, the duration of pattern events,
+ * in events per cycle. `tight` doesn't have structure itself, but takes structure, and therefore
+ * event durations, from the pattern that it is combined with.
+ * For example `tight.struct("1 1 [1 1] 1")` would give the same as `"4 4 [8 8] 4"`.
+ * See also its inverse, `loose`.
+ * @example
+ * // Shorter events are more distorted
+ * n("0 0*2 0 0*2 0 [0 0 0]@2").sound("bd")
+ *  .distort(tight.div(2))
+ */
+export const tight = new Pattern(function (state) {
+  return [new Hap(undefined, state.span, Fraction(1).div(state.span.duration))];
+});
+
+/**
+ * Like `tight` but gives the tightness of events according to an exponential curve. In
+ * particular, where the event tightness doubles (i.e. where an event duration halves), the
+ * returned value increases by one. `tightx.struct("1 1 1 [1 [1 1]]")` would therefore be
+ * the same as `"3 3 3 [4 [5 5]]"`.
+ */
+export const tightx = new Pattern(function (state) {
+  const n = Fraction(1).div(state.span.duration);
+  return [new Hap(undefined, state.span, Math.log(n) / Math.log(2) + 1)];
+});
diff --git a/packages/core/test/pattern.test.mjs b/packages/core/test/pattern.test.mjs
index 408ff274..aaa14bd2 100644
--- a/packages/core/test/pattern.test.mjs
+++ b/packages/core/test/pattern.test.mjs
@@ -740,20 +740,6 @@ describe('Pattern', () => {
       );
     });
   });
-  describe('signal()', () => {
-    it('Can make saw/saw2', () => {
-      expect(saw.struct(true, true, true, true).firstCycle()).toStrictEqual(
-        sequence(0, 1 / 4, 1 / 2, 3 / 4).firstCycle(),
-      );
-
-      expect(saw2.struct(true, true, true, true).firstCycle()).toStrictEqual(sequence(-1, -0.5, 0, 0.5).firstCycle());
-    });
-    it('Can make isaw/isaw2', () => {
-      expect(isaw.struct(true, true, true, true).firstCycle()).toStrictEqual(sequence(1, 0.75, 0.5, 0.25).firstCycle());
-
-      expect(isaw2.struct(true, true, true, true).firstCycle()).toStrictEqual(sequence(1, 0.5, 0, -0.5).firstCycle());
-    });
-  });
   describe('_setContext()', () => {
     it('Can set the hap context', () => {
       expect(