refactor: prepare for boolean functions

* Defines a BooleanT type
  * adds options to the Type constructor, so far just to allow conversions
    from other types
  * renames Number type to NumberT
  * records the name of types, and puts the name in the string representation
  * defines a conversion fron BooleanT to NumberT, specified to be automatic
  * stub code for automatic conversions, not yet complete
  * BooleanT not yet added to nanomath

Checked that the new facilities do not disrupt the prior behavior on numbers.

src/boolean/BooleanT.js

@@ -0,0 +1,3 @@
+import {Type} from '#core/Type.js'
+
+export const BooleanT = new Type(n => typeof n === 'boolean')

src/core/Type.js

@@ -3,8 +3,13 @@ const typeObject = {} // have to make sure there is only one
 export const types = () => typeObject
 
 export class Type {
-   constructor(f) {
+   constructor(f, options = {}) {
       this.test = f
+      this.from = options.from ?? []
+      this.from.push(this)
+   }
+   toString() {
+      return this.name || `[Type ${this.test}]`
    }
 }
 

src/core/TypeDispatcher.js

@@ -3,9 +3,12 @@ import {typeOf, Type, bootstrapTypes} from './Type.js'
 import {
    Implementations, isPlainFunction, isPlainObject, onType
 } from './helpers.js'
-import {alwaysMatches, Any, Multiple} from './TypePatterns.js'
+import {
+   alwaysMatches, matched, needsCollection, Any, Multiple
+} from './TypePatterns.js'
 
 // helper that organizes a list into the same chunks as a pattern is
+// NOTE NOTE: need to update to handle conversions!
 const collectLike = (list, pattern, state = {pos: 0}) => {
    const result = []
    for (const elt of pattern) {
@@ -41,6 +44,7 @@ export class TypeDispatcher {
          if (val instanceof Type) {
             // TODO: Need to wipe out any dependencies on types[key]!
             this.types[key] = val
+            val.name = key
             continue
          }
          if (typeof val === 'function') {
@@ -161,13 +165,16 @@ export class TypeDispatcher {
       let pattern
       let template
       if (imps.length) {
-         for ([pattern, item] of imps) {
-            let finalIndex
-            ;[finalIndex, template] = pattern.match(types)
-            if (finalIndex === types.length) {
-               needItem = false
-               break
+         for (const options of [{}, {convert: true}]) {
+            for ([pattern, item] of imps) {
+               let finalIndex
+               ;[finalIndex, template] = pattern.match(types, options)
+               if (finalIndex === types.length) {
+                  needItem = false
+                  break
+               }
             }
+            if (!needItem) break
          }
       }
       if (needItem && key in this._fallbacks) {
@@ -190,7 +197,8 @@ export class TypeDispatcher {
       this.resolve._genDepsOf.push([key, types])
       let theBehavior = () => undefined
       try {
-         theBehavior = item(DependencyRecorder(this, [], this), template)
+         theBehavior = item(
+            DependencyRecorder(this, [], this), matched(template))
       } catch {
          behave.set(types, item)
          return item
@@ -199,8 +207,7 @@ export class TypeDispatcher {
       }
       if (typeof theBehavior === 'function'
           && theBehavior.length
-          && Array.isArray(template)
-          && template.some(elt => Array.isArray(elt))
+          && needsCollection(template)
       ) {
          // have to wrap the behavior to collect the actual arguments
          // in the way corresponding to the template

src/core/TypePatterns.js

@@ -1,7 +1,7 @@
 import {Type, Undefined} from './Type.js'
 
 export class TypePattern {
-   match(typeSequence, position = 0) {
+   match(typeSequence, options={}) {
       throw new Error('Specific TypePatterns must implement match')
    }
    sampleTypes() {
@@ -15,10 +15,16 @@ class MatchTypePattern extends TypePattern {
       super()
       this.type = typeToMatch
    }
-   match(typeSequence, position = 0) {
+   match(typeSequence, options={}) {
+      const position = options.position ?? 0
+      const allowed = options.convert ? this.type.from : [this.type]
       if (position < typeSequence.length
-         && typeSequence[position] === this.type
+          && allowed.includes(typeSequence[position])
       ) {
+         let templateItem = typeSequence[position]
+         if (templateItem !== this.type) {
+            templateItem = {actual: templateItem, matched: this.type}
+         }
          return [position + 1, typeSequence[position]]
       }
       return [-1, Undefined]
@@ -32,15 +38,19 @@ class SequencePattern extends TypePattern {
       super()
       this.patterns = itemsToMatch.map(pattern)
    }
-   match(typeSequence, position = 0) {
+   match(typeSequence, options={_internal: true}) {
+      options = options._internal
+         ? options
+         : Object.assign({_internal: true}, options)
+      options.position ??= 0
       const matches = []
       for (const pat of this.patterns) {
-         const [newPos, newMatch] = pat.match(typeSequence, position)
+         const [newPos, newMatch] = pat.match(typeSequence, options)
          if (newPos < 0) return [-1, Undefined]
-         position = newPos
+         options.position = newPos
          matches.push(newMatch)
       }
-      return [position, matches]
+      return [options.position, matches]
    }
    sampleTypes() {
       return this.patterns.map(pat => pat.sampleTypes()).flat()
@@ -62,7 +72,8 @@ export const pattern = patternOrSpec => {
 }
 
 class AnyPattern extends TypePattern {
-   match(typeSequence, position = 0) {
+   match(typeSequence, options={}) {
+      const position = options.position ?? 0
       return position < typeSequence.length
          ? [position + 1, typeSequence[position]]
          : [-1, Undefined]
@@ -77,14 +88,18 @@ class OptionalPattern extends TypePattern {
       super()
       this.pattern = pattern(item)
    }
-   match(typeSequence, position = 0) {
+   match(typeSequence, options={_internal: true}) {
+      options = options._internal
+         ? options
+         : Object.assign({_internal: true}, options)
+      options.position ??= 0
       const matches = []
-      const [newPos, newMatch] = this.pattern.match(typeSequence, position)
+      const [newPos, newMatch] = this.pattern.match(typeSequence, options)
       if (newPos >= 0) {
-         position = newPos
+         options.position = newPos
          matches.push(newMatch)
       }
-      return [position, matches]
+      return [options.position, matches]
    }
    sampleTypes() {return []}
    equal(other) {
@@ -99,12 +114,16 @@ class MultiPattern extends TypePattern {
       super()
       this.pattern = pattern(item)
    }
-   match(typeSequence, position = 0) {
+   match(typeSequence, options={_internal: true}) {
+      options = options._internal
+         ? options
+         : Object.assign({_internal: true}, options)
+      options.position ??= 0
       const matches = []
       while (true) {
-         const [newPos, newMatch] = this.pattern.match(typeSequence, position)
-         if (newPos < 0) return [position, matches]
-         position = newPos
+         const [newPos, newMatch] = this.pattern.match(typeSequence, options)
+         if (newPos < 0) return [options.position, matches]
+         options.position = newPos
          matches.push(newMatch)
       }
    }
@@ -117,3 +136,18 @@ class MultiPattern extends TypePattern {
 export const Multiple = item => new MultiPattern(item)
 export const alwaysMatches =
    pat => pat instanceof MultiPattern && pat.pattern instanceof AnyPattern
+
+// returns the template just of matched types, dropping any actual types
+export const matched = (template) => {
+   if (Array.isArray(template)) return template.map(matched)
+   return template.matched ?? template
+}
+
+// checks if the template is just pass-through or needs collection
+export const needsCollection = (template) => {
+   if (Array.isArray(template)) {
+      return template.some(
+         elt => Array.isArray(elt) || needsCollection(elt))
+   }
+   return 'actual' in template
+}

src/core/__test__/Type.spec.js

@@ -1,14 +1,14 @@
 import assert from 'assert'
 import math from '#nanomath'
-import {Number} from '#number/Number.js'
+import {NumberT} from '#number/NumberT.js'
 
 import {Returns} from '../Type.js'
 import {isPlainFunction} from '../helpers.js'
 
 describe('Core types', () => {
    it('creates an object with all of the types', () => {
-      assert('Number' in math.types)
-      assert.strictEqual(math.types.Number, Number)
+      assert('NumberT' in math.types)
+      assert.strictEqual(math.types.NumberT, NumberT)
       assert('Undefined' in math.types)
       assert(!('Type' in math.types))
       assert(math.types.Undefined.test(undefined))
@@ -18,9 +18,9 @@ describe('Core types', () => {
 
    it('supports a typeOf operator', () => {
       const tO = math.typeOf
-      assert.strictEqual(tO(7), Number)
+      assert.strictEqual(tO(7), NumberT)
       assert.strictEqual(tO(undefined), math.types.Undefined)
-      assert.strictEqual(tO(Number), math.types.TypeOfTypes)
+      assert.strictEqual(tO(NumberT), math.types.TypeOfTypes)
       assert.throws(() => tO(Symbol()), TypeError)
    })
 

src/core/__test__/TypeDispatcher.spec.js

@@ -13,8 +13,8 @@ describe('TypeDispatcher', () => {
       assert.strictEqual(
          incremental.typeOf(undefined), incremental.types.Undefined)
       incremental.merge(numbers)
-      const {Number, TypeOfTypes, Undefined} = incremental.types
-      assert(Number.test(7))
+      const {NumberT, TypeOfTypes, Undefined} = incremental.types
+      assert(NumberT.test(7))
       assert.strictEqual(incremental.add(-1.5, 0.5), -1)
       // Make Undefined act like zero:
       incremental.merge({add: onType(
@@ -27,18 +27,18 @@ describe('TypeDispatcher', () => {
          TypeOfTypes)
       assert.strictEqual(incremental.add(undefined, -3.25), -3.25)
       assert.strictEqual(
-         incremental.add.resolve([Undefined, Number]).returns,
-         Number)
+         incremental.add.resolve([Undefined, NumberT]).returns,
+         NumberT)
       // Oops, changed my mind, make it work like NaN with numbers:
-      const alwaysNaN = Returns(Number, () => NaN)
+      const alwaysNaN = Returns(NumberT, () => NaN)
       incremental.merge({add: onType(
-         [Undefined, Number], alwaysNaN,
-         [Number, Undefined], alwaysNaN
+         [Undefined, NumberT], alwaysNaN,
+         [NumberT, Undefined], alwaysNaN
       )})
       assert(isNaN(incremental.add(undefined, -3.25)))
       assert.strictEqual(
-         incremental.add.resolve([Undefined, Number]).returns,
-         Number)
+         incremental.add.resolve([Undefined, NumberT]).returns,
+         NumberT)
    })
    it('changes methods when their dependencies change', () => {
       const gnmath = new TypeDispatcher(generics, numbers)

src/core/helpers.js

@@ -1,13 +1,18 @@
-import {Type} from './Type.js'
 import {pattern} from './TypePatterns.js'
 
 export class Implementations {
    constructor(imps) {
       this.patterns = new Map()
+      this._add(imps)
+   }
+   _add(imps) {
       for (let i = 0; i < imps.length; ++i) {
          this.patterns.set(pattern(imps[i]), imps[++i])
       }
    }
+   also(...imps) {
+      this._add(imps)
+   }
 }
 
 export const onType = (...imps) => new Implementations(imps)

src/generic/__test__/arithmetic.spec.js

@@ -5,7 +5,7 @@ describe('generic arithmetic', () => {
    it('squares anything', () => {
       assert.strictEqual(math.square(7), 49)
       assert.strictEqual(
-         math.square.resolve([math.types.Number]).returns,
-         math.types.Number)
+         math.square.resolve([math.types.NumberT]).returns,
+         math.types.NumberT)
    })
 })

src/number/Number.js

@@ -1,3 +0,0 @@
-import {Type} from '#core/Type.js'
-
-export const Number = new Type(n => typeof n === 'number')

src/number/NumberT.js

@@ -0,0 +1,6 @@
+import {Type} from '#core/Type.js'
+import {BooleanT} from '#boolean/BooleanT.js'
+
+export const NumberT = new Type(n => typeof n === 'number', {
+    from: [BooleanT]
+})

src/number/__test__/Number.spec.js

@@ -1,11 +0,0 @@
-import assert from 'assert'
-import {Number} from '../Number.js'
-
-describe('Number Type', () => {
-   it('correctly recognizes numbers', () => {
-      assert(Number.test(3))
-      assert(Number.test(NaN))
-      assert(Number.test(Infinity))
-      assert(!Number.test("3"))
-   })
-})

src/number/__test__/NumberT.spec.js

@@ -0,0 +1,11 @@
+import assert from 'assert'
+import {NumberT} from '../NumberT.js'
+
+describe('NumberT Type', () => {
+   it('correctly recognizes numbers', () => {
+      assert(NumberT.test(3))
+      assert(NumberT.test(NaN))
+      assert(NumberT.test(Infinity))
+      assert(!NumberT.test("3"))
+   })
+})

src/number/all.js

@@ -1,4 +1,4 @@
-export * as typeDefinition from './Number.js'
+export * as typeDefinition from './NumberT.js'
 export * as arithmetic from './arithmetic.js'
 export * as type from './type.js'
 export * as utils from './utils.js'

src/number/helpers.js

@@ -1,7 +1,7 @@
-import {Number} from './Number.js'
+import {NumberT} from './NumberT.js'
 
 import {onType} from '#core/helpers.js'
 import {Returns} from '#core/Type.js'
 
 export const plain = f => onType(
-   Array(f.length).fill(Number), Returns(Number, f))
+   Array(f.length).fill(NumberT), Returns(NumberT, f))

src/number/type.js

@@ -1,4 +1,7 @@
 import {plain} from './helpers.js'
+import {BooleanT} from '#boolean/BooleanT.js'
+import {Returns} from '#core/Type.js'
+import {NumberT} from '#number/NumberT.js'
 
-// Not much to do so far when there is only one type
 export const number = plain(a => a)
+number.also(BooleanT, Returns(NumberT, a => a ? 1 : 0))

src/package.json

@@ -1,6 +1,7 @@
 {
     "imports" : {
         "#nanomath": "./nanomath.js",
+        "#boolean/*.js": "./boolean/*.js",
         "#core/*.js": "./core/*.js",
         "#number/*.js": "./number/*.js"
     },