Fix stepjoin (#1067)

* sort fractions properly - fixes #1066

packages/core/pattern.mjs

@@ -43,7 +43,7 @@ export class Pattern {
   constructor(query, tactus = undefined) {
     this.query = query;
     this._Pattern = true; // this property is used to detect if a pattern that fails instanceof Pattern is an instance of another Pattern
-    this.__tactus = tactus; // in terms of number of beats per cycle
+    this.__tactus = Fraction(tactus); // in terms of number of steps per cycle
   }
 
   get tactus() {

packages/core/test/pattern.test.mjs

@@ -1146,7 +1146,7 @@ describe('Pattern', () => {
       expect(sameFirst(sequence(0, 1, 2, 3, 4).s_taper(-1, 5), sequence(0, 0, 1, 0, 1, 2, 0, 1, 2, 3, 0, 1, 2, 3, 4)));
     });
   });
-  describe('s_add and s_sub, left', () => {
+  describe('s_add and s_sub', () => {
     it('can add from the left', () => {
       expect(sameFirst(sequence(0, 1, 2, 3, 4).s_add(2), sequence(0, 1)));
     });
@@ -1159,5 +1159,14 @@ describe('Pattern', () => {
     it('can sub to the right', () => {
       expect(sameFirst(sequence(0, 1, 2, 3, 4).s_sub(-2), sequence(2, 3, 4)));
     });
+    it('can subtract nothing', () => {
+      expect(sameFirst(pure('a').s_sub(0), pure('a')));
+    });
+    it('can subtract nothing, repeatedly', () => {
+      expect(sameFirst(pure('a').s_sub(0, 0), fastcat('a', 'a')));
+      for (var i = 0; i < 100; ++i) {
+        expect(sameFirst(pure('a').s_sub(...Array(i).fill(0)), fastcat(...Array(i).fill('a'))));
+      }
+    });
   });
 });

packages/core/util.mjs

@@ -319,9 +319,11 @@ export function uniqsort(a) {
 
 // rational version
 export function uniqsortr(a) {
-  return a.sort().filter(function (item, pos, ary) {
-    return !pos || item.ne(ary[pos - 1]);
-  });
+  return a
+    .sort((x, y) => x.compare(y))
+    .filter(function (item, pos, ary) {
+      return !pos || item.ne(ary[pos - 1]);
+    });
 }
 
 // code hashing helpers