Merge pull request 'refactor: Simpler merging mechanism' (#33) from merge_instances into main

Reviewed-on: #33

src/bigint/Types/bigint.mjs

@@ -1,4 +1,7 @@
-export const Type_bigint = {
+import PocomathInstance from '../../core/PocomathInstance.mjs'
+const BigInt = new PocomathInstance('BigInt')
+BigInt.installType('bigint', {
     before: ['Complex'],
     test: b => typeof b === 'bigint'
-}
+})
+export {BigInt}

src/bigint/all.mjs

@@ -1,8 +1,5 @@
-export * from './native.mjs'
+import PocomathInstance from '../core/PocomathInstance.mjs'
-export * from '../generic/arithmetic.mjs'
+import * as bigints from './native.mjs'
+import * as generic from '../generic/arithmetic.mjs'
 
-// resolve the conflicts
+export default PocomathInstance.merge('bigint', bigints, generic)
-export {divide} from './divide.mjs'
-export {multiply} from './multiply.mjs'
-export {sign} from './sign.mjs'
-export {sqrt} from './sqrt.mjs'

src/complex/Types/Complex.mjs

@@ -1,3 +1,5 @@
+import PocomathInstance from '../../core/PocomathInstance.mjs'
+
 /* Use a plain object with keys re and im for a complex; note the components
  * can be any type (for this proof-of-concept; in reality we'd want to
  * insist on some numeric or scalar supertype).
@@ -6,11 +8,13 @@ function isComplex(z) {
    return z && typeof z === 'object' && 're' in z && 'im' in z
 }
 
-export const Type_Complex = {
+const Complex = new PocomathInstance('Complex')
+Complex.installType('Complex', {
    test: isComplex,
    from: {
       number: x => ({re: x, im: 0}),
       bigint: x => ({re: x, im: 0n})
    }
-}
+})
 
+export {Complex}

src/complex/all.mjs

@@ -1,5 +1,5 @@
-export * from '../generic/arithmetic.mjs'
+import PocomathInstance from '../core/PocomathInstance.mjs'
-export * from './native.mjs'
+import * as complexes from './native.mjs'
+import * as generic from '../generic/arithmetic.mjs'
 
-// resolve the conflicts
+export default PocomathInstance.merge('complex', complexes, generic)
-export {sqrt} from './sqrt.mjs'

src/complex/sqrt.mjs

@@ -35,7 +35,6 @@ export const sqrt = {
          const reSign = sign(z.re)
          if (imSign === imZero && reSign === reOne) return self(z.re)
          const reTwo = add(reOne, reOne)
-         const partial = add(abs(z), z.re)
          return complex(
             multiply(sign(z.im), self(divide(add(abs(z),z.re), reTwo))),
             self(divide(subtract(abs(z),z.re), reTwo))

src/core/PocomathInstance.mjs

@@ -3,13 +3,20 @@ import typed from 'typed-function'
 import dependencyExtractor from './dependencyExtractor.mjs'
 import {subsetOfKeys, typesOfSignature} from './utils.mjs'
 
+const anySpec = {} // fixed dummy specification of 'any' type
+
 export default class PocomathInstance {
    /* Disallowed names for ops; beware, this is slightly non-DRY
     * in that if a new top-level PocomathInstance method is added, its name
     * must be added to this list.
     */
    static reserved = new Set([
-      'config', 'importDependencies', 'install', 'name', 'Types'])
+      'config',
+      'importDependencies',
+      'install',
+      'installType',
+      'name',
+      'Types'])
 
    constructor(name) {
       this.name = name
@@ -17,7 +24,7 @@ export default class PocomathInstance {
       this._affects = {}
       this._typed = typed.create()
       this._typed.clear()
-      this.Types = {any: {}} // dummy entry to track the default 'any' type
+      this.Types = {any: anySpec} // dummy entry to track the default 'any' type
       this._doomed = new Set() // for detecting circular reference
       this._config = {predictable: false}
       const self = this
@@ -36,9 +43,19 @@ export default class PocomathInstance {
    /**
     * (Partially) define one or more operations of the instance:
     *
-    * @param {Object<string, Object<Signature, ({deps})=> implementation>>} ops
+    * The sole parameter can be another Pocomath instance, in which case all
+    * of the types and operations of the other instance are installed in this
+    * one, or it can be a plain object as described below.
+    *
+    * @param {Object<string,
+    *                PocomathInstance
+    *                | Object<Signature, ({deps})=> implementation>>} ops
     *    The only parameter ops gives the semantics of the operations to install.
-    *    The keys are operation names. The value for a key is an object
+    *    The keys are operation names. The value for a key could be
+    *    a PocomathInstance, in which case it is simply merged into this
+    *    instance.
+    *
+    *    Otherwise, ops must be an object
     *    mapping each desired (typed-function) signature to a function taking
     *    a dependency object to an implementation.
     *
@@ -63,29 +80,55 @@ export default class PocomathInstance {
     *    with the signature in parentheses, e.g. `add(number,number)` to
     *    refer to just adding two numbers. In this case, it is of course
     *    necessary to specify an alias to be able to refer to the supplied
-    *    operation in the body of the implementation. [NOTE: this signature-
+    *    operation in the body of the implementation.
-    *    specific reference is not yet implemented.]
-    *
-    *    Note that any "operation" whose name begins with  `Type_` is special:
-    *    it defines a types that must be installed in the instance.
-    *    The remainder of the "operation" name following the `_` is the
-    *    name of the type. The value of the "operation" should be a plain
-    *    object with the following properties:
-    *
-    *    - test: the predicate for the type
-    *    - from: a plain object mapping the names of types that can be converted
-    *        **to** this type to the corresponding conversion functions
-    *    - before: [optional] a list of types this should be added
-    *        before, in priority order
     */
    install(ops) {
+      if (ops instanceof PocomathInstance) {
+         return _installInstance(ops)
+      }
+      /* Standardize the format of all implementations, weeding out
+       * any other instances as we go
+       */
+      const stdFunctions = {}
       for (const [item, spec] of Object.entries(ops)) {
-         if (item.slice(0,5) === 'Type_') {
+         if (spec instanceof PocomathInstance) {
-            this._installType(item.slice(5), spec)
+            this._installInstance(spec)
          } else {
-            this._installOp(item, spec)
+            if (item.charAt(0) === '_') {
+               throw new SyntaxError(
+                  `Pocomath: Cannot install ${item}, `
+                     + 'initial _ reserved for internal use.')
+            }
+            if (PocomathInstance.reserved.has(item)) {
+               throw new SyntaxError(
+                  `Pocomath: reserved function '${item}' cannot be modified.`)
+            }
+            const stdimps = {}
+            for (const [signature, does] of Object.entries(spec)) {
+               const uses = new Set()
+               does(dependencyExtractor(uses))
+               stdimps[signature] = {uses, does}
+            }
+            stdFunctions[item] = stdimps
          }
       }
+      this._installFunctions(stdFunctions)
+   }
+
+   /* Merge any number of PocomathInstances or modules:  */
+   static merge(name, ...pieces) {
+      const result = new PocomathInstance(name)
+      for (const piece of pieces) {
+         result.install(piece)
+      }
+      return result
+   }
+
+   _installInstance(other) {
+      for (const [type, spec] of Object.entries(other.Types)) {
+         this.installType(type, spec)
+      }
+      this._installFunctions(other._imps)
    }
 
    /**
@@ -127,10 +170,29 @@ export default class PocomathInstance {
       }
    }
 
-   /* Used internally by install, see the documentation there.
+   /* Used to install a type in a PocomathInstance.
-    * Note that unlike _installOp below, we can do this immediately
+    *
+    * @param {string} name  The name of the type
+    * @param {{test: any => bool,  // the predicate for the type
+    *          from: Record<string, <that type> => <type name>> // conversions
+    *          before: string[]  // lower priority types
+    *        }} specification
+    *
+    * The second parameter of this function specifies the structure of the
+    * type via a plain
+    *    object with the following properties:
+    *
+    *    - test: the predicate for the type
+    *    - from: a plain object mapping the names of types that can be converted
+    *        **to** this type to the corresponding conversion functions
+    *    - before: [optional] a list of types this should be added
+    *        before, in priority order
     */
-   _installType(type, spec) {
+   /*
+    * Implementation note: unlike _installFunctions below, we can make
+    * the corresponding changes to the _typed object immediately
+    */
+   installType(type, spec) {
       if (type in this.Types) {
          if (spec !== this.Types[type]) {
             throw new SyntaxError(`Conflicting definitions of type ${type}`)
@@ -165,30 +227,20 @@ export default class PocomathInstance {
    }
 
    /* Used internally by install, see the documentation there */
-   _installOp(name, implementations) {
+   _installFunctions(functions) {
-      if (name.charAt(0) === '_') {
+      for (const [name, spec] of Object.entries(functions)) {
-         throw new SyntaxError(
-            `Pocomath: Cannot install ${name}, `
-               + 'initial _ reserved for internal use.')
-      }
-      if (PocomathInstance.reserved.has(name)) {
-         throw new SyntaxError(
-            `Pocomath: the meaning of function '${name}' cannot be modified.`)
-      }
          // new implementations, so set the op up to lazily recreate itself
          this._invalidate(name)
          const opImps = this._imps[name]
-      for (const [signature, does] of Object.entries(implementations)) {
+         for (const [signature, behavior] of Object.entries(spec)) {
             if (signature in opImps) {
-            if (does !== opImps[signature].does) {
+               if (behavior.does !== opImps[signature].does) {
                   throw new SyntaxError(
                      `Conflicting definitions of ${signature} for ${name}`)
                }
             } else {
-            const uses = new Set()
+               opImps[signature] = behavior
-            does(dependencyExtractor(uses))
+               for (const dep of behavior.uses) {
-            opImps[signature] = {uses, does}
-            for (const dep of uses) {
                   const depname = dep.split('(', 1)[0]
                   if (depname === 'self') continue
                   this._addAffect(depname, name)
@@ -199,6 +251,7 @@ export default class PocomathInstance {
             }
          }
       }
+   }
 
    _addAffect(dependency, dependent) {
       if (dependency in this._affects) {

src/generic/Types/generic.mjs

@@ -1,2 +1,5 @@
-export const Type_undefined = {test: u => u === undefined}
+import PocomathInstance from '../../core/PocomathInstance.mjs'
+const Undefined = new PocomathInstance('Undefined')
+Undefined.installType('undefined', {test: u => u === undefined})
+export {Undefined}
 

src/number/Types/number.mjs

@@ -1,6 +1,8 @@
-export const Type_number = {
+import PocomathInstance from '../../core/PocomathInstance.mjs'
+const Number = new PocomathInstance('Number')
+Number.installType('number', {
     before: ['Complex'],
     test: n => typeof n === 'number',
     from: {string: s => +s}
-}
+})
-
+export {Number}

src/number/all.mjs

@@ -1,6 +1,6 @@
-export * from '../generic/arithmetic.mjs'
+import PocomathInstance from '../core/PocomathInstance.mjs'
-export * from './native.mjs'
+import * as numbers from './native.mjs'
+import * as generic from '../generic/arithmetic.mjs'
+
+export default PocomathInstance.merge('number', numbers, generic)
 
-// resolve the conflicts
-export {sqrt} from './sqrt.mjs'
-export {multiply} from './multiply.mjs'

src/pocomath.mjs

@@ -5,10 +5,6 @@ import * as bigints from './bigint/native.mjs'
 import * as complex from './complex/native.mjs'
 import * as generic from './generic/all.mjs'
 
-const math = new PocomathInstance('math')
+const math = PocomathInstance.merge('math', numbers, bigints, complex, generic)
-math.install(numbers)
-math.install(bigints)
-math.install(complex)
-math.install(generic)
 
 export default math

test/_pocomath.mjs

@@ -18,14 +18,14 @@ describe('The default full pocomath instance "math"', () => {
    })
 
    it('can be extended', () => {
+      math.installType('stringK', {
+         test: s => typeof s === 'string' && s.charAt(0) === 'K',
+         before: ['string']
+      })
       math.install({
          add: {
             '...stringK': () => addends => addends.reduce((x,y) => x+y, '')
          },
-         Type_stringK: {
-            test: s => typeof s === 'string' && s.charAt(0) === 'K',
-            before: ['string']
-         }
       })
       assert.strictEqual(math.add('Kilroy','K is here'), 'KilroyK is here')
    })

test/custom.mjs

@@ -23,7 +23,7 @@ describe('A custom instance', () => {
 
    it("can be assembled in any order", () => {
       bw.install(numbers)
-      bw.install({Type_string: {test: s => typeof s === 'string'}})
+      bw.installType('string', {test: s => typeof s === 'string'})
       assert.strictEqual(bw.subtract(16, bw.add(3,4,2)), 7)
       assert.strictEqual(bw.negate('8'), -8)
       assert.deepStrictEqual(bw.add(bw.complex(1,3), 1), {re: 2, im: 3})