Implement binary prefixes for no reason

ref #211

README.md

@@ -254,7 +254,7 @@ Records are accessed with the same syntax as arrays but using string indices e.g
 Nullish access is supported e.g. `{}~["nothing here"]` evaluates to `niente`.
 
 ## Metric prefixes
-Frequency literals support [metric prefixes](https://en.wikipedia.org/wiki/Metric_prefix) e.g. `1.2 kHz` is the same as `1200 Hz`.
+Frequency literals support [metric prefixes](https://en.wikipedia.org/wiki/Metric_prefix) e.g. `1.2 kHz` is the same as `1200 Hz`. [Binary prefixes](https://en.wikipedia.org/wiki/Binary_prefix) are also supported for no particular reason.
 
 ## Numeric frequency flavor
 The space is mandatory in frequency literals like `123 hz` but there is a numeric *flavor* 'z' for quick input i.e. `123z`.

src/__tests__/parser/expression.spec.ts

@@ -1751,4 +1751,10 @@ describe('SonicWeave expression evaluator', () => {
     const thirdFourth = parseSingle('⅓M2_7l');
     expect(thirdFourth.toFraction().toFraction()).toBe('11/10');
   });
+
+  it('has binary prefixes for mild amusement', () => {
+    const tooLong = parseSingle('3 Yis');
+    expect(tooLong.isAbsolute()).toBe(true);
+    expect(tooLong.valueOf()).toBeCloseTo(3 * 1024 ** 8);
+  });
 });

src/expression.ts

@@ -1,5 +1,6 @@
 import {
   ABSURD_EXPONENT,
+  BinaryPrefix,
   MetricPrefix,
   Sign,
   bigAbs,
@@ -104,12 +105,12 @@ export type ReciprocalCentLiteral = {
 
 export type HertzLiteral = {
   type: 'HertzLiteral';
-  prefix: MetricPrefix;
+  prefix: MetricPrefix | BinaryPrefix;
 };
 
 export type SecondLiteral = {
   type: 'SecondLiteral';
-  prefix: MetricPrefix;
+  prefix: MetricPrefix | BinaryPrefix;
 };
 
 export type FJS = {

src/parser.ts

@@ -57,6 +57,9 @@ import {
   NEGATIVE_ONE,
   TWO,
   hasOwn,
+  binaryExponent,
+  MetricPrefix,
+  BinaryPrefix,
 } from './utils';
 import {pythagoreanMonzo, absoluteMonzo} from './pythagorean';
 import {inflect} from './fjs';
@@ -1016,6 +1019,7 @@ export class StatementVisitor {
 
 const TWO_MONZO = new TimeMonzo(ZERO, [ONE]);
 const TEN_MONZO = new TimeMonzo(ZERO, [ONE, ZERO, ONE]);
+const KIBI_MONZO = new TimeMonzo(ZERO, [new Fraction(10)]);
 const CENT_MONZO = new TimeMonzo(ZERO, [new Fraction(1, 1200)]);
 const RECIPROCAL_CENT_MONZO = new TimeMonzo(ZERO, [new Fraction(1200)]);
 
@@ -2273,13 +2277,23 @@ export class ExpressionVisitor {
   }
 
   visitHertzLiteral(node: HertzLiteral): Interval {
-    const value = TEN_MONZO.pow(metricExponent(node.prefix));
+    let value: TimeMonzo;
+    if (node.prefix.endsWith('i')) {
+      value = KIBI_MONZO.pow(binaryExponent(node.prefix as BinaryPrefix));
+    } else {
+      value = TEN_MONZO.pow(metricExponent(node.prefix as MetricPrefix));
+    }
     value.timeExponent = NEGATIVE_ONE;
     return new Interval(value, 'linear', node);
   }
 
   visitSecondLiteral(node: SecondLiteral): Interval {
-    const value = TEN_MONZO.pow(metricExponent(node.prefix));
+    let value: TimeMonzo;
+    if (node.prefix.endsWith('i')) {
+      value = KIBI_MONZO.pow(binaryExponent(node.prefix as BinaryPrefix));
+    } else {
+      value = TEN_MONZO.pow(metricExponent(node.prefix as MetricPrefix));
+    }
     value.timeExponent = ONE;
     return new Interval(value, 'linear', node);
   }

src/sonic-weave.pegjs

@@ -1097,15 +1097,15 @@ HertzLiteral
       prefix: '',
     }
   }
-  / prefix: MetricPrefix? (HertzToken / LowHertzToken) {
+  / prefix: (BinaryPrefix / MetricPrefix)? (HertzToken / LowHertzToken) {
     return {
       type: 'HertzLiteral',
       prefix,
     };
   }
 
 SecondLiteral
-  = prefix: MetricPrefix? SecondToken {
+  = prefix: (BinaryPrefix / MetricPrefix)? SecondToken {
     return {
       type: 'SecondLiteral',
       prefix,
@@ -1428,6 +1428,10 @@ ParenthesizedExpression
 MetricPrefix
   = $([QRYZEPTGMkhdcmµnpfazyrq] / 'da' / '')
 
+// Note: According to Wikipedia Ri and Qi are still under review.
+BinaryPrefix
+  = $([KMGTPEZYRQ] 'i')
+
 StringLiteral
   = '"' chars: DoubleStringCharacter* '"' { return { type: 'StringLiteral', value: chars.join('') }; }
   / "'" chars: SingleStringCharacter* "'" { return { type: 'StringLiteral', value: chars.join('') }; }

src/utils.ts

@@ -141,7 +141,46 @@ export function metricExponent(prefix: MetricPrefix): number {
     case 'q':
       return -30;
     default:
-      throw new Error(`Unrecognized prefix ${prefix}`);
+      throw new Error(`Unrecognized prefix ${prefix}.`);
+  }
+}
+
+export type BinaryPrefix =
+  | 'Ki'
+  | 'Mi'
+  | 'Gi'
+  | 'Ti'
+  | 'Pi'
+  | 'Ei'
+  | 'Zi'
+  | 'Yi'
+  | 'Ri'
+  | 'Qi';
+
+export function binaryExponent(prefix: BinaryPrefix): number {
+  switch (prefix) {
+    case 'Ki':
+      return 1;
+    case 'Mi':
+      return 2;
+    case 'Gi':
+      return 3;
+    case 'Ti':
+      return 4;
+    case 'Pi':
+      return 5;
+    case 'Ei':
+      return 6;
+    case 'Zi':
+      return 7;
+    case 'Yi':
+      return 8;
+    case 'Ri':
+      return 9;
+    case 'Qi':
+      return 10;
+    default:
+      throw new Error(`Unrecognized prefix ${prefix}.`);
   }
 }