feat: Barest outline of a Dispatcher, providing only typeOf so far

src/Complex/type.ts

@@ -14,7 +14,9 @@ export const Complex_type = {
          typeof z === 'object' && z != null && 're' in z && 'im' in z
          && dep.testT(z.re) && dep.testT(z.im),
    infer: (dep: {typeOf: CommonSignature<undefined>['typeOf']}) =>
-      (z: Complex<unknown>) => joinTypes(dep.typeOf(z.re), dep.typeOf(z.im)),
+      (z: Complex<unknown>) => ({
+          T: joinTypes(dep.typeOf(z.re), dep.typeOf(z.im))
+      }),
    from: {
       Complex: <U,T>(dep: {convert: CommonSignature<U,T>['convert']}) =>
          (z: Complex<U>): Complex<T> =>

src/core/Dispatcher.ts

@@ -1,3 +1,4 @@
+import {inspect} from 'node:util'
 import type {AnyFunc, CommonSignature, GenSigs} from '@/interfaces/type'
 
 // A base type that roughly describes the dependencies of a single factory
@@ -102,10 +103,6 @@ type Implementations<
    Specs extends Specifications<Signatures, NeedKeys, NeedList>
 > = {[K in NeedKeys]: ImpType<Signatures, K, Specs[K]>}
 
-export interface ReflectedTypeInfo {
-   reflectedType5: string
-}
-
 // The builder interface that lets us assemble narrowly-typed Implementations:
 interface ImplementationBuilder<
    Signatures extends GenSigs,
@@ -139,7 +136,7 @@ interface ImplementationBuilder<
       Specs & {[K in NewKeys]: DepCheck<RD, Signatures>}
    >
 
-   done(info?: ReflectedTypeInfo): Implementations<Signatures, NeedKeys, NeedList, Specs> & ReflectedTypeInfo
+   done(): Implementations<Signatures, NeedKeys, NeedList, Specs>
 }
 
 // And a function that actually provides the builder interface:
@@ -191,8 +188,8 @@ function impBuilder<
              Specs & {[K in NewKeys]: DepCheck<RD, Signatures, DepKeys>}
           >
       },
-      done(info?: ReflectedTypeInfo) {
+      done() {
-         return { ...sofar, ...info }
+         return sofar
       }
    }
 }
@@ -202,3 +199,124 @@ export function implementations<Signatures extends GenSigs>(
 ): ImplementationBuilder<Signatures, never, {}, {}> {
    return impBuilder({})
 }
+
+// Now we turn to creating a Dispatcher itself. For this we use loose types,
+// and rely on the type annotations from our special build for runtime type
+// identification.
+
+type Callable = (...args: any) => any
+type Implementation = {implementation: Callable}
+type Factory = {factory: Callable, dependencies: Record<string, any>}
+type Reflected = {_reflectedType5: any}
+type TypeSpec = {
+    name: string,
+    before?: string[],
+    test: Callable,
+    from: Record<string, Callable>,
+    infer?: Callable
+}
+type ImpItem = Implementation | Factory
+type ImpGroup = Record<string,  ImpItem>
+
+// When this is being compiled, TypeScript can't tell that the
+// ImpSpecification entities will have been reflected:
+type ImpSpecification = (ImpGroup | (() => ImpGroup) | TypeSpec) // & Reflected
+
+interface ImpSpecs extends Record<string, ImpSpecification | ImpSpecs> {}
+
+type ImpHolder = {
+    implementations: Record<string, Callable>, // Key is a signature
+    factories: Record<string, Factory>
+}
+
+type DispatcherInstance = {
+    implementationData: Record<string, ImpHolder>, // Key is an operation name
+    types: TypeSpec[], // Order is order to try types in
+    behaviors: Record<string, Callable>, // Key is opname; actually executable!
+}
+
+function newDispatcherInstance(): DispatcherInstance {
+    return {
+        implementationData: {},
+        types: [],
+        behaviors: {}
+    }
+}
+
+function isTypeSpec(spec: ImpSpecification | ImpSpecs): spec is TypeSpec {
+    if ('name' in spec
+        && typeof spec.name === 'string'
+        && 'test' in spec
+        && 'from' in spec
+       ) {
+        return true
+    }
+    return false
+}
+
+// The assemble function creates a dispatcher from a mess of specifications
+export function assemble(specifications: ImpSpecs, into?: DispatcherInstance ) {
+    if (into === undefined) {
+        into = newDispatcherInstance()
+        const show = inspect(specifications, {depth: 18, colors: true})
+        console.log('Specifications are', show)
+    }
+    for (const specName in specifications) {
+        console.log('Processing', specName)
+        const spec = specifications[specName]
+        if ('_reflectedType5' in spec) {
+            if (isTypeSpec(spec)) {
+                registerTypeSpec(spec, into)
+                continue
+            }
+            // implementations that we need to deal with
+            console.log('Need to incorporate', Object.keys(spec))
+        } else {
+            // Just another layer of specification
+            assemble(spec as ImpSpecs, into)
+        }
+    }
+    into.behaviors.typeOf = (a: unknown) => whichType(a, into.types)
+    return into.behaviors
+}
+
+function registerTypeSpec(typeSpec: TypeSpec, into: DispatcherInstance) {
+    let position = into.types.length
+    if ('before' in typeSpec) {
+        for (const typeName of typeSpec.before) {
+            const typeIndex = into.types.findIndex(t => t.name = typeName)
+            if (typeIndex >= 0 && typeIndex < position) position = typeIndex
+        }
+    }
+    into.types.splice(position, 0, typeSpec)
+    // likely there will be more to do in the long run
+}
+
+// Returns the string name of the type of _a_ per the type specifications
+// in _types_, or 'unknown' if no type matches
+function whichType(a: unknown, types: TypeSpec[]) {
+    for (const typeSpec of types) {
+        const typeName = typeSpec.name
+        // First check if this is a ground type or a generic:
+        const typeSpecType = (typeSpec as TypeSpec & Reflected)._reflectedType5
+        if (!('_typeParameters' in typeSpecType.test)) {
+            // ground type, just test it
+            if (typeSpec.test(a)) return typeName
+            continue
+        }
+        // Generic type. In this case, the test will be a factory, dependent
+        // on a test for each of the type parameters. So assemble those
+        // dependencies:
+        const typePars = typeSpecType.test._typeParameters
+        const permissiveTests = Object.fromEntries(typePars.map(k =>
+            [`test${k}`, x => true]))
+        const testAllUnknown = typeSpec.test(permissiveTests)
+        if (!testAllUnknown(a)) continue
+        // Here, a seems to be in some instantiation of this generic type.
+        // Need to infer which instantiation
+        const thisInfer = typeSpec.infer({typeOf: x => whichType(x, types)})
+        const typeArguments = thisInfer(a)
+        return `${typeName}<${typePars.map(k => typeArguments[k]).join(',')}>`
+    }
+    return 'unknown'
+}

src/index.ts

@@ -1,5 +1,10 @@
-import {inspect} from 'node:util'
+import {assemble} from '@/core/Dispatcher'
-
 import * as specifications from './all'
 
-console.log(inspect(specifications, {depth: 18, colors: true}))
+const math = assemble(specifications)
+console.log('PRODUCED', math)
+
+console.log(math.typeOf(17))
+console.log(math.typeOf({re: 3.4, im: -0.1}))
+console.log(math.typeOf({re: {re: 1, im: 0}, im: {re: 0, im: -1}}))
+console.log(math.typeOf('no string type yet'))