test: Add tests for all existing functionality, correcting issues (#9)

Resolves #8.

Reviewed-on: #9
Co-authored-by: Glen Whitney <glen@studioinfinity.org>
Co-committed-by: Glen Whitney <glen@studioinfinity.org>

src/core/Type.js

@@ -1,9 +1,4 @@
-import {Returns} from './helpers.js'
-
-// Order matters here, because these items will merged into a new
-// dispatcher in the order they are listed
-
-const typeObject = {}
+const typeObject = {} // have to make sure there is only one
 
 export const types = () => typeObject
 
@@ -16,11 +11,20 @@ export class Type {
 export const Undefined = new Type(t => typeof t === 'undefined')
 export const TypeOfTypes = new Type(t => t instanceof Type)
 
+export const Returns = (type, f) => (f.returns = type, f)
+
 export const typeOf = Returns(TypeOfTypes, item => {
    for (const type of Object.values(typeObject)) {
       if (!(type instanceof Type)) continue
       if (type.test(item)) return type
    }
+   let errorMsg = ''
+   try {
+      errorMsg = `no known type for '${item}'` // fails for Symbols, e.g.
+   } catch {
+      errorMsg = `no known type for '${item.toString()}'`
+   }
+   throw new TypeError(errorMsg)
 })
 
 // bootstrapping order matters, but order of exports in a module isn't

src/core/TypeDispatcher.js

@@ -1,6 +1,8 @@
 import {typeOf, Type, bootstrapTypes} from './Type.js'
 
-import {Implementations, isPlainObject, onType} from './helpers.js'
+import {
+   Implementations, isPlainFunction, isPlainObject, onType
+} from './helpers.js'
 import {alwaysMatches, Any, Multiple} from './TypePatterns.js'
 
 // helper that organizes a list into the same chunks as a pattern is
@@ -64,7 +66,7 @@ export class TypeDispatcher {
                      }
                      // Redefine the property according to what sort of
                      // entity it is:
-                     if (typeof tryValue === 'function') {
+                     if (isPlainFunction(tryValue)) {
                         // the usual case: a method of the dispatcher
                         const standard = (...args) => {
                            const types = args.map(typeOf)
@@ -161,7 +163,7 @@ export class TypeDispatcher {
       if (imps.length) {
          for ([pattern, item] of imps) {
             let finalIndex
-            ;[finalIndex, template] = pattern.match(types, 0)
+            ;[finalIndex, template] = pattern.match(types)
             if (finalIndex === types.length) {
                needItem = false
                break
@@ -176,7 +178,7 @@ export class TypeDispatcher {
       if (needItem) {
          throw new TypeError(`no matching definition of '${key}' on '${types}'`)
       }
-      if (typeof item !== 'function' || 'returns' in item) {
+      if (!isPlainFunction(item) || 'returns' in item) {
          behave.set(types, item)
          return item
       }
@@ -186,8 +188,17 @@ export class TypeDispatcher {
          this.resolve._genDepsOf = []
       }
       this.resolve._genDepsOf.push([key, types])
-      let theBehavior = item(DependencyRecorder(this, [], this), pattern)
-      this.resolve._genDepsOf.pop()
+      let theBehavior = () => undefined
+      try {
+         theBehavior = item(DependencyRecorder(this, [], this), template)
+      } catch {
+         // Didn't work as a factory, so guess we were wrong; just
+         // make this entity the behavior:
+         behave.set(types, item)
+         return item
+      } finally {
+         this.resolve._genDepsOf.pop()
+      }
       if (typeof theBehavior === 'function'
           && theBehavior.length
           && template.some(elt => Array.isArray(elt))

src/core/TypePatterns.js

@@ -1,7 +1,7 @@
 import {Type, Undefined} from './Type.js'
 
-class TypePattern {
-   match(typeSequence, position) {
+export class TypePattern {
+   match(typeSequence, position = 0) {
       throw new Error('Specific TypePatterns must implement match')
    }
    sampleTypes() {
@@ -15,7 +15,7 @@ class MatchTypePattern extends TypePattern {
       super()
       this.type = typeToMatch
    }
-   match(typeSequence, position) {
+   match(typeSequence, position = 0) {
       if (position < typeSequence.length
          && typeSequence[position] === this.type
       ) {
@@ -32,7 +32,7 @@ class SequencePattern extends TypePattern {
       super()
       this.patterns = itemsToMatch.map(pattern)
    }
-   match(typeSequence, position) {
+   match(typeSequence, position = 0) {
       const matches = []
       for (const pat of this.patterns) {
          const [newPos, newMatch] = pat.match(typeSequence, position)
@@ -62,7 +62,7 @@ export const pattern = patternOrSpec => {
 }
 
 class AnyPattern extends TypePattern {
-   match(typeSequence, position) {
+   match(typeSequence, position = 0) {
       return position < typeSequence.length
          ? [position + 1, typeSequence[position]]
          : [-1, Undefined]
@@ -74,9 +74,10 @@ export const Any = new AnyPattern()
 
 class OptionalPattern extends TypePattern {
    constructor(item) {
+      super()
       this.pattern = pattern(item)
    }
-   match(typeSequence, position) {
+   match(typeSequence, position = 0) {
       const matches = []
       const [newPos, newMatch] = this.pattern.match(typeSequence, position)
       if (newPos >= 0) {
@@ -98,7 +99,7 @@ class MultiPattern extends TypePattern {
       super()
       this.pattern = pattern(item)
    }
-   match(typeSequence, position) {
+   match(typeSequence, position = 0) {
       const matches = []
       while (true) {
          const [newPos, newMatch] = this.pattern.match(typeSequence, position)

src/core/__test__/Type.spec.js

@@ -0,0 +1,43 @@
+import assert from 'assert'
+import math from '#nanomath'
+import {Number} from '#number/Number.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('Undefined' in math.types)
+      assert(!('Type' in math.types))
+      assert(math.types.Undefined.test(undefined))
+      assert(!math.types.Undefined.test(3))
+      assert(math.types.TypeOfTypes.test(math.types.Undefined))
+   })
+
+   it('supports a typeOf operator', () => {
+      const tO = math.typeOf
+      assert.strictEqual(tO(7), Number)
+      assert.strictEqual(tO(undefined), math.types.Undefined)
+      assert.strictEqual(tO(Number), math.types.TypeOfTypes)
+      assert.throws(() => tO(Symbol()), TypeError)
+   })
+
+   it('lets you create a new Type', () => {
+      const Foo = new math.Type(
+         item => item && typeof item === 'object' && 'bar' in item)
+      assert(Foo.test({bar: 'baz'}))
+      math.merge({Foo})
+      assert.strictEqual(math.types.Foo, Foo)
+      assert.strictEqual(math.typeOf({gold: 7, bar: 3}), Foo)
+   })
+
+   it('provides a return-value labeling', () => {
+      const labeledF = Returns(math.types.Undefined, () => undefined)
+      assert.strictEqual(typeof labeledF, 'function')
+      assert.strictEqual(labeledF.returns, math.types.Undefined)
+      assert(isPlainFunction(labeledF))
+   })
+
+})

src/core/__test__/TypeDispatcher.spec.js

@@ -0,0 +1,41 @@
+import assert from 'assert'
+import {TypeDispatcher} from '../TypeDispatcher.js'
+import {numbers} from '../../numbers.js'
+import {onType} from "#core/helpers.js"
+import {Any} from "#core/TypePatterns.js"
+import {Returns} from "#core/Type.js"
+
+describe('TypeDispatcher', () => {
+   it('can build in stages', () => {
+      const incremental = new TypeDispatcher()
+      assert.strictEqual(
+         incremental.typeOf(undefined), incremental.types.Undefined)
+      incremental.merge(numbers)
+      const {Number, TypeOfTypes, Undefined} = incremental.types
+      assert(Number.test(7))
+      assert.strictEqual(incremental.add(-1.5, 0.5), -1)
+      // Make Undefined act like zero:
+      incremental.merge({add: onType(
+         [Undefined, Any], (_m, [_U, T]) => Returns(T, (_a, b) => b),
+         [Any, Undefined], (_m, [T]) => Returns(T, a => a)
+      )})
+      assert.strictEqual(incremental.add(7, undefined), 7)
+      assert.strictEqual(
+         incremental.resolve('add', [TypeOfTypes, Undefined]).returns,
+         TypeOfTypes)
+      assert.strictEqual(incremental.add(undefined, -3.25), -3.25)
+      assert.strictEqual(
+         incremental.add.resolve([Undefined, Number]).returns,
+         Number)
+      // Oops, changed my mind, make it work like NaN with numbers:
+      const alwaysNaN = Returns(Number, () => NaN)
+      incremental.merge({add: onType(
+         [Undefined, Number], alwaysNaN,
+         [Number, Undefined], alwaysNaN
+      )})
+      assert(isNaN(incremental.add(undefined, -3.25)))
+      assert.strictEqual(
+         incremental.add.resolve([Undefined, Number]).returns,
+         Number)
+   })
+})

src/core/__test__/TypePatterns.spec.js

@@ -0,0 +1,96 @@
+import assert from 'assert'
+import {pattern, Any, Multiple, Optional} from '../TypePatterns.js'
+import {Undefined, TypeOfTypes} from '../Type.js'
+
+describe('Type patterns', () => {
+   it('makes patterns from types and sequences thereof', () => {
+      const undef1 = pattern(Undefined)
+      assert.deepStrictEqual(undef1.match([Undefined]), [1, Undefined])
+      assert.deepStrictEqual(
+         undef1.match([Undefined, Undefined]), [1, Undefined])
+      assert.deepStrictEqual(undef1.match([TypeOfTypes]), [-1, Undefined])
+      assert.deepStrictEqual(undef1.match([]), [-1, Undefined])
+      assert.deepStrictEqual(undef1.sampleTypes(), [Undefined])
+      assert(undef1.equal(pattern(Undefined)))
+      assert(!undef1.equal(pattern(TypeOfTypes)))
+      const tu2 = pattern([TypeOfTypes, undef1])
+      assert.deepStrictEqual(
+         tu2.match([Undefined, TypeOfTypes]), [-1, Undefined])
+      assert.deepStrictEqual(
+         tu2.match([TypeOfTypes, Undefined]), [2, [TypeOfTypes, Undefined]])
+   })
+
+   it('allows Any as a wildcard', () => {
+      const midWild = pattern([Undefined, Any, TypeOfTypes])
+      assert.deepStrictEqual(
+         midWild.match([Undefined, Undefined, TypeOfTypes]),
+         [3, [Undefined, Undefined, TypeOfTypes]])
+      assert.deepStrictEqual(
+         midWild.match([Undefined, TypeOfTypes, TypeOfTypes]),
+         [3, [Undefined, TypeOfTypes, TypeOfTypes]])
+      assert.deepStrictEqual(
+         midWild.match([Undefined, TypeOfTypes, Undefined]),
+         [-1, Undefined])
+      assert.deepStrictEqual(
+         midWild.match([Undefined, TypeOfTypes]),
+         [-1, Undefined])
+      assert.deepStrictEqual(
+         midWild.sampleTypes(), [Undefined, Undefined, TypeOfTypes])
+      assert(midWild.equal(midWild))
+      assert(!midWild.equal(pattern([Any, Any, TypeOfTypes])))
+   })
+
+   it("supports greedy multiple and optional parameters", () => {
+      const midOpt = pattern([Undefined, Optional(TypeOfTypes), Undefined])
+      assert.deepStrictEqual(
+         midOpt.match([Undefined, Undefined]), [2, [Undefined, [], Undefined]])
+      assert.deepStrictEqual(
+         midOpt.match([Undefined, TypeOfTypes, Undefined]),
+         [3, [Undefined, [TypeOfTypes], Undefined]])
+      assert.deepStrictEqual(
+         midOpt.match([Undefined, TypeOfTypes, TypeOfTypes]),
+         [-1, Undefined])
+      assert.deepStrictEqual(midOpt.sampleTypes(), [Undefined, Undefined])
+      const midMulti = pattern([Undefined, Multiple(TypeOfTypes), Undefined])
+      assert.deepStrictEqual(
+         midMulti.match([Undefined, Undefined]),
+         [2, [Undefined, [], Undefined]])
+      assert.deepStrictEqual(
+         midMulti.match([Undefined, TypeOfTypes, Undefined]),
+         [3, [Undefined, [TypeOfTypes], Undefined]])
+      assert.deepStrictEqual(
+         midMulti.match(
+            [Undefined, TypeOfTypes, TypeOfTypes, TypeOfTypes, Undefined]),
+         [5, [Undefined, [TypeOfTypes, TypeOfTypes, TypeOfTypes], Undefined]])
+      assert.deepStrictEqual(
+         midMulti.match([Undefined, TypeOfTypes, TypeOfTypes]),
+         [-1, Undefined])
+      assert.deepStrictEqual(midOpt.sampleTypes(), [Undefined, Undefined])
+      assert(!midMulti.equal(midOpt))
+      const whyNot = pattern(
+         [Undefined, Multiple([Undefined, TypeOfTypes]), TypeOfTypes])
+      assert.deepStrictEqual(
+         whyNot.match([Undefined, TypeOfTypes]),
+         [2, [Undefined, [], TypeOfTypes]])
+      assert.deepStrictEqual(
+         whyNot.match([Undefined, Undefined, TypeOfTypes, TypeOfTypes]),
+         [4, [Undefined, [[Undefined, TypeOfTypes]], TypeOfTypes]])
+      assert.deepStrictEqual(
+         whyNot.match([
+            Undefined,
+            Undefined, TypeOfTypes, Undefined, TypeOfTypes,
+            TypeOfTypes
+         ]),
+         [6, [
+            Undefined,
+            [[Undefined, TypeOfTypes], [Undefined, TypeOfTypes]],
+            TypeOfTypes
+         ]])
+      assert.deepStrictEqual(
+         whyNot.match([Undefined, TypeOfTypes, Undefined, TypeOfTypes]),
+         [2, [Undefined, [], TypeOfTypes]])
+      assert.deepStrictEqual(
+         whyNot.sampleTypes(), [Undefined, TypeOfTypes])
+      assert(whyNot.equal(whyNot))
+   })
+})

src/core/__test__/helpers.spec.js

@@ -0,0 +1,35 @@
+import assert from 'assert'
+import {
+   Implementations, onType, isPlainObject, isPlainFunction
+} from '../helpers.js'
+import {Type, Undefined, TypeOfTypes} from '../Type.js'
+import {TypePattern} from '../TypePatterns.js'
+
+describe('Core helpers', () => {
+   it('defines what Implementations are', () => {
+      const imps = onType(Undefined, 7, [TypeOfTypes, Undefined], -3)
+      assert(imps instanceof Implementations)
+      assert(imps.patterns instanceof Map)
+      assert(imps.patterns.keys().every(k => k instanceof TypePattern))
+   })
+
+   it('detects plain objects', () => {
+      assert(!isPlainObject(Undefined))
+      assert(!isPlainObject([2, 3, 4]))
+      assert(!isPlainObject('pat'))
+      assert(isPlainObject({plain: 'object'}))
+      assert(isPlainObject({}))
+   })
+
+   it('detects plain functions (not constructors)', () => {
+      function embedded() {return 1}
+      class Embedded {}
+      assert(isPlainFunction(embedded))
+      assert(isPlainFunction(() => 'wow'))
+      assert(isPlainFunction(it))
+      assert(!isPlainFunction(7))
+      assert(!isPlainFunction(Implementations))
+      assert(!isPlainFunction(Type))
+      assert(!isPlainFunction(Embedded))
+   })
+})

src/core/helpers.js

@@ -12,11 +12,35 @@ export class Implementations {
 
 export const onType = (...imps) => new Implementations(imps)
 
-export const Returns = (type, f) => (f.returns = type, f)
-
-export const isPlainObject = (obj) => {
+export const isPlainObject = obj => {
    if (typeof obj !== 'object') return false
    if (!obj) return false // excludes null
    const proto = Object.getPrototypeOf(obj)
    return !proto || proto === Object.prototype
 }
+
+// Class entities have typeof === 'function', but mostly we do not
+// want to treat them like ordinary functions, hence we need some way
+// of telling. There doesn't seem to be a definitive way, so we
+// use a mishmash of techniques from
+// https://stackoverflow.com/questions/526559
+const isClass = f => {
+   if (!f.prototype) return false
+   if (f.constructor !== Function) return false
+   const protoCtor = f.prototype.constructor
+   if (protoCtor
+       && protoCtor.toString
+       && protoCtor.toString().startsWith('class')
+   ) {
+      return true
+   }
+   if (Object.getPrototypeOf(f) !== Function.prototype) return true
+   if (Object.getOwnPropertyNames(f).includes('arguments')) return false
+   return Object.getOwnPropertyNames(f.prototype).length > 1
+}
+
+// returns true for functions that are not class constructors, at
+// least so far as we can tell:
+export const isPlainFunction = f => {
+   return typeof f === 'function' && !isClass(f)
+}

src/number/__test__/type.spec.js

@@ -0,0 +1,8 @@
+import assert from 'assert'
+import math from '#nanomath'
+
+describe('number type operations', () => {
+   it('converts to number', () => {
+      assert.strictEqual(math.number(2.637), 2.637)
+   })
+})

src/number/__test__/utils.spec.js

@@ -0,0 +1,8 @@
+import assert from 'assert'
+import math from '#nanomath'
+
+describe('number utilities', () => {
+   it('clones a number', () => {
+      assert.strictEqual(math.clone(2.637), 2.637)
+   })
+})

src/number/helpers.js

@@ -1,5 +1,7 @@
-import {Returns, onType} from '#core/helpers.js'
 import {Number} from './Number.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))

src/package.json

@@ -1,7 +1,8 @@
 {
     "imports" : {
         "#nanomath": "./nanomath.js",
-        "#core/*.js": "./core/*.js"
+        "#core/*.js": "./core/*.js",
+        "#number/*.js": "./number/*.js"
     },
     "type" : "module"
 }