Various MOS fixes

ref #326

package.json

@@ -67,8 +67,8 @@
     "vitest": "^1.4.0"
   },
   "dependencies": {
-    "moment-of-symmetry": "^0.7.0",
-    "xen-dev-utils": "^0.7.0"
+    "moment-of-symmetry": "^0.8.0",
+    "xen-dev-utils": "^0.8.0"
   },
   "engines": {
     "node": ">=12.0.0"

src/diamond-mos.ts

@@ -117,7 +117,13 @@ export type AbsoluteMosPitch = {
  */
 export function scaleMonzos(config: MosConfig) {
   const entries = Array.from(config.scale);
-  entries.sort((a, b) => a[0].localeCompare(b[0]));
+  entries.sort((a, b) =>
+    a[0].length < b[0].length
+      ? -1
+      : a[0].length > b[0].length
+        ? 1
+        : a[0].localeCompare(b[0])
+  );
   const monzos = entries.map(entry => entry[1]);
   monzos.push(monzos.shift()!.mul(config.equave) as TimeMonzo);
   return monzos;

src/monzo.ts

@@ -14,6 +14,7 @@ import {
   monzoToCents,
   sum,
   primeFactorize,
+  modc,
 } from 'xen-dev-utils';
 
 import {
@@ -636,10 +637,7 @@ export class TimeReal {
     }
     const modulus = other.valueOf();
     if (ceiling) {
-      return new TimeReal(
-        this.timeExponent,
-        mmod(this.value, modulus) || modulus
-      );
+      return new TimeReal(this.timeExponent, modc(this.value, modulus));
     }
     return new TimeReal(this.timeExponent, mmod(this.value, modulus));
   }
@@ -2221,10 +2219,9 @@ export class TimeMonzo {
       return result;
     }
     const modulus = other.valueOf();
-    let value = mmod(this.valueOf(), modulus);
-    if (ceiling) {
-      value = value || modulus;
-    }
+    const value = ceiling
+      ? modc(this.valueOf(), modulus)
+      : mmod(this.valueOf(), modulus);
     return new TimeReal(this.timeExponent.valueOf(), value);
   }
 

src/parser/__tests__/source.spec.ts

@@ -1794,4 +1794,33 @@ describe('SonicWeave parser', () => {
       'J5 "91\\\\91"',
     ]);
   });
+
+  it('has automos that works with two-character nominals', () => {
+    const scale = expand(`
+      MOS 9L 9s
+      automos()
+      i => nedji(i, niente, 27)
+    `);
+    expect(scale).toEqual([
+      'MOS {LsLsLsLsLsLsLsLsLs;L=2^2/27;s=2^1/27}',
+      '2\\27',
+      '3\\27',
+      '5\\27',
+      '6\\27',
+      '8\\27',
+      '9\\27',
+      '11\\27',
+      '12\\27',
+      '14\\27',
+      '15\\27',
+      '17\\27',
+      '18\\27',
+      '20\\27',
+      '21\\27',
+      '23\\27',
+      '24\\27',
+      '26\\27',
+      '27\\27',
+    ]);
+  });
 });

src/parser/__tests__/stdlib.spec.ts

@@ -1512,4 +1512,30 @@ describe('SonicWeave standard library', () => {
       '18\\18',
     ]);
   });
+
+  it('produces MOS scales of negative hardness', () => {
+    const scale = expand('mos(5, 2, 2, -1)');
+    expect(scale).toEqual([
+      '2\\8',
+      '4\\8',
+      '6\\8',
+      '5\\8',
+      '7\\8',
+      '9\\8',
+      '8\\8',
+    ]);
+  });
+
+  it('produces descending MOS scales', () => {
+    const scale = expand('mos(5, 2, -2, -1, 5)');
+    expect(scale).toEqual([
+      '-2\\12',
+      '-4\\12',
+      '-5\\12',
+      '-7\\12',
+      '-9\\12',
+      '-11\\12',
+      '-12\\12',
+    ]);
+  });
 });

src/parser/mos.ts

@@ -12,7 +12,12 @@ import {
 } from '../ast';
 import {TimeMonzo, TimeReal} from '../monzo';
 import {ExpressionVisitor} from './expression';
-import {MosMonzo, MosOptions, generateNotation, mos} from 'moment-of-symmetry';
+import {
+  MosMonzo,
+  MosOptions,
+  generateNotation,
+  stepString,
+} from 'moment-of-symmetry';
 import {Interval} from '../interval';
 import {MosConfig, MosDegree} from '../diamond-mos';
 import {ONE, TWO, ZERO} from '../utils';
@@ -229,19 +234,7 @@ export class Tardigrade {
         throw new Error('Period must be consistent with counts if given.');
       }
     }
-    // moment-of-symmetry generates the brightest mode by default
-    const basic = mos(node.countLarge, node.countSmall, options);
-    let pattern = '';
-    let previous = 0;
-    for (const step of basic) {
-      if (step - previous === 2) {
-        pattern += 'L';
-      } else {
-        pattern += 's';
-      }
-      previous = step;
-    }
-    this.pattern = pattern;
+    this.pattern = stepString(node.countLarge, node.countSmall, options);
     if (node.equave) {
       this.equave = this.visitRationalEquave(node.equave);
     }

src/stdlib/prelude.ts

@@ -474,7 +474,7 @@ riff mos(numberOfLargeSteps, numberOfSmallSteps, sizeOfLargeStep = 2, sizeOfSmal
   Alternatively \`down\` defines the darkness of the mode i.e. the number of minor intervals from the root. \\
   The default \`equave\` is the octave \`2/1\`.";
   mosSubset(numberOfLargeSteps, numberOfSmallSteps, sizeOfLargeStep, sizeOfSmallStep, up, down);
-  const divisions = $[-1];
+  const divisions = abs $[-1];
   if (equave == 2)
     step => step \\ divisions;
   else