refactor: Extend reflection to all implementations so far

And also enhances the reflected type parsing so that the types of all
  implementations so far will parse.

package.json5

@@ -1,6 +1,6 @@
 {
    name: 'typocomath',
-   version: '0.0.1',
+   version: '0.0.2',
    description: 'A hopeful final typescipt-pragmatic mathjs proof-of-concept',
    main: 'index.ts',
    scripts: {

src/Complex/predicate.ts

@@ -1,9 +1,13 @@
 import {Complex} from './type.js'
 import type {Dependencies, Signature} from '../interfaces/type.js'
+import {$reflect} from '../interfaces/type.js'
 
 export const isReal =
    <T>(dep: Dependencies<'add' | 'equal' | 'isReal', T>):
       Signature<'isReal', Complex<T>> =>
    z => dep.isReal(z.re) && dep.equal(z.re, dep.add(z.re, z.im))
 
-export const isSquare: Signature<'isSquare', Complex<any>> = z => true // FIXME: not correct for Complex<bigint> once we get there
+export const isSquare = (): Signature<'isSquare', Complex<unknown>> =>
+   z => true // FIXME: not correct for Complex<bigint> once we get there
+
+$reflect!([isReal, isSquare])

src/Complex/relational.ts

@@ -1,6 +1,8 @@
 import {Complex} from './type.js'
 import {Dependencies, Signature} from '../interfaces/type.js'
+import {$reflect} from '../interfaces/type.js'
 
 export const equal =
    <T>(dep: Dependencies<'equal', T>): Signature<'equal', Complex<T>> =>
    (w, z) => dep.equal(w.re, z.re) && dep.equal(w.im, z.im)
+$reflect!([equal])

src/Complex/type.ts

@@ -2,6 +2,7 @@ import {joinTypes, typeOfDependency} from '../core/Dispatcher.js'
 import type {
    ZeroType, OneType, NaNType, Dependencies, Signature, Returns
 } from '../interfaces/type.js'
+import {$reflect} from '../interfaces/type.js'
 
 export type Complex<T> = { re: T; im: T; }
 
@@ -62,3 +63,5 @@ export const nan =
 export const re =
    <T>(dep: Dependencies<'re', T>): Signature<'re', Complex<T>> =>
    z => dep.re(z.re)
+
+$reflect!([complex, zero, one, nan, re])

src/core/Dispatcher.ts

@@ -5,6 +5,8 @@
  * for specific types (including their own).
  */
 
+import {parseReflectedType, ImplementationDef} from './parseReflectedType.js'
+
 // First helper types and functions for the Dispatcher
 
 type TypeName = string
@@ -39,19 +41,17 @@ type SpecificationsGroup = Record<string, SpecObject>
 export class Dispatcher {
    installSpecification(
       name: string,
-      signature: Signature,
-      returns: TypeName,
-      dependencies: Record<string, Signature>,
+      defn: ImplementationDef,
       behavior: Function // possible todo: constrain this type based
       // on the signature, return type, and dependencies. Not sure if
       // that's really possible, though.
    ) {
-      console.log('Pretending to install', name, signature, '=>', returns)
-      // @ts-ignore
-      if (behavior.reflectedType) {
-         // @ts-ignore
-         console.log('  Reflected type:', behavior.reflectedType)
-         // TODO: parse the reflected type
+      console.log('Pretending to install', name, 'with signatures')
+      for (const signature of defn.fn.signatures) {
+         console.log('   ', signature.args, '=>', signature.returns)
+      }
+      if (defn.fn.aliasOf) {
+         console.log('   As an alias of', defn.fn.aliasOf)
       }
       //TODO: implement me
    }
@@ -77,7 +77,8 @@ export class Dispatcher {
       for (const trio of implementations) {
          const [k, id, imp] = trio
          console.log('Handling implementation', id, 'from', k)
-         this.installSpecification(id, ['dunno'], 'unsure', {}, imp)
+         this.installSpecification(
+            id, parseReflectedType(id, imp.reflectedType), imp)
       }
    }
 }

src/core/parseReflectedType.ts

@@ -1,14 +1,16 @@
-export interface FunctionDef {
+export type FunctionDef {
   name: string,
+  aliasOf?: string,
   signatures: Array<{
     args: Array<{ name: string, type: string }>
-    // FIXME: remove undefined in the end
-    returns: string | undefined
+    returns: string
   }>
 }
 
-export interface DependencyDef extends FunctionDef {
-  aliasOf: string | undefined
+
+export type ImplementationDef = {
+  fn: FunctionDef,
+  dependencies: Record<string, FunctionDef>
 }
 
 /**
@@ -16,101 +18,116 @@ export interface DependencyDef extends FunctionDef {
  *
  *   '<T>(dep: configDependency & { complex: ((re: number) => Complex<number>) | ((re: number, im: number) => Complex<number>); }) => (a: number) => number | Complex<number>'
  */
-export function parseReflectedType(name: string, reflectedType: string) : { fn: FunctionDef, dependencies: Record<string, DependencyDef> } {
-  const [factoryArgs, fnArgsBlock, returns] = split(reflectedType, '=>').map(trim)
-  const args = parseArgs(fnArgsBlock)
+export function parseReflectedType(name: string, reflectedType: string): ImplementationDef {
+  console.log('For', name, 'parsing', reflectedType)
+  const [factoryArgs, fnsClause] = split(reflectedType, '=>', 2).map(trim)
+  const fn = parseAlias(name, fnsClause)
 
   const factoryArgsInner = findBlockContents(factoryArgs, '(', ')')
   const depArg = split(factoryArgsInner.innerText, ':').map(trim)[1]
-  const depArgBlocks = split(depArg, '&').map(trim)
+  const depArgBlocks: string[] = depArg ? split(depArg, '&').map(trim) : []
 
   const deps = depArgBlocks
     .filter(depArgBlock => {
-      if (depArgBlock.startsWith('{')) {
+      if (depArgBlock.startsWith('{') || depArgBlock === 'configDependency') {
         return true
       } else {
-        console.error(`ERROR: Cannot parse dependency "${depArgBlock}"`)
+        throw new SyntaxError(`Cannot parse dependency "${depArgBlock}"`)
       }
     })
     .flatMap(parseDependencies)
 
-  const dependencies: Record<string, DependencyDef> = groupBy(deps, 'name')
+  const dependencies: Record<string, FunctionDef> = groupBy(deps, 'name')
 
-  return {
-    fn: { name, signatures: [{args, returns}] },
-    dependencies
+  return {fn, dependencies}
+}
+
+function parseDependencies(deps: string): FunctionDef[] {
+  if (deps === 'configDependency') {
+    return [{name: 'config', signatures: [{args: [], returns: 'Config'}]}]
   }
+  const inner = findBlockContents(deps, '{', '}').innerText
+  return split(inner, ';')
+    .map(trim)
+    .filter(notEmpty)
+    .map(parseDependency)
+}
 
-  function parseDependencies(deps: string) {
-    const inner = findBlockContents(deps, '{', '}').innerText
-    return split(inner, ';')
-      .map(trim)
-      .filter(notEmpty)
-      .map(parseDependency)
-  }
+// parse a dependency like "complex: ((re: number) => Complex<number>) | ((re: number, im: number) => Complex<number>)"
+function parseDependency(dep: string): FunctionDef {
+  const [name, def] = split(dep, ':').map(trim)
 
-  // parse a dependency like "complex: ((re: number) => Complex<number>) | ((re: number, im: number) => Complex<number>)"
-  function parseDependency(dep: string) {
-    const [name, def] = split(dep, ':').map(trim)
+  return parseAlias(name, def)
+}
 
-    const { aliasOf, innerSignature } = parseAliasOf(def)
+// Parse a possibly aliased function
+function parseAlias(name: string, alias: string): FunctionDef {
+  const { aliasOf, innerSignature } = parseAliasOf(alias)
 
-    const signatures = split(innerSignature, '|')
-      .map(trim)
-      .map(stripParenthesis)
-      .map(signature => {
-        const [argsBlock, returns] = split(signature, '=>').map(trim)
+  return { name, signatures: parseSignatures(innerSignature), aliasOf }
+}
 
-        if (!returns) {
-          console.warn(`ERROR: failed to find return type in '${signature}'`)
-        }
+// parse function signatures like ((re: number) => Complex<number>) | ((re: number, im: number) => Complex<number>)
+// But also have to succeed on (a: number) => number | Complex<number>
+// That's why we only split on an alternation bar `|` that's followed by
+// a parenthesis; that way we avoid splitting a union return type. Note
+// this is not necessarily foolproof, as there could be a return type that
+// is a union with a complicated piece that has to be enclosed in parens;
+// but so far it seems to work in practice.
+function parseSignatures(sigs: string) {
+  return split(sigs, /[|]\s*(?=[(])/)
+    .map(trim)
+    .map(stripParenthesis)
+    .map(signature => {
+      const [argsBlock, returns] = split(signature, '=>').map(trim)
 
-        return {
-          args: parseArgs(argsBlock),
-          returns
-        }
-      })
-
-    return { name, signatures, aliasOf }
-  }
-
-  // parse args like "(re: number, im: number)"
-  function parseArgs(argsBlock: string) : Array<{name: string, type: string}> {
-    const args = findBlockContents(argsBlock, '(', ')').innerText
-
-    return split(args, ',')
-      .map(trim)
-      .map(arg => {
-        const [name, type] = split(arg, ':').map(trim)
-        return { name, type}
-      })
-  }
-
-  // parse "AliasOf<"divide", (a: Complex<T>, b: RealType<Complex<T>>) => Complex<T>>"
-  function parseAliasOf(signature: string) : { innerSignature: string, aliasOf: string | undefined } {
-    if (!signature.startsWith('AliasOf')) {
-      return {
-        innerSignature: signature,
-        aliasOf: undefined
+      if (!returns) {
+        throw new SyntaxError(`Failed to find return type in '${signature}'`)
       }
-    }
 
-    const inner = findBlockContents(signature, '<', '>').innerText.trim()
-    const [aliasOfWithQuotes, innerSignature] = split(inner, ',').map(trim)
+      return {
+        args: parseArgs(argsBlock),
+        returns
+      }
+    })
+}
+
+// parse args like "(re: number, im: number)"
+function parseArgs(argsBlock: string) : Array<{name: string, type: string}> {
+  const args = findBlockContents(argsBlock, '(', ')').innerText
+
+  return split(args, ',')
+    .map(trim)
+    .map(arg => {
+      const [name, type] = split(arg, ':').map(trim)
+      return { name, type}
+    })
+}
+
+// parse "AliasOf<"divide", (a: Complex<T>, b: RealType<Complex<T>>) => Complex<T>>"
+function parseAliasOf(signature: string) : { innerSignature: string, aliasOf: string | undefined } {
+  if (!signature.startsWith('AliasOf')) {
     return {
-      innerSignature,
-      aliasOf: aliasOfWithQuotes.substring(1, aliasOfWithQuotes.length - 1) // remove double quotes
+      innerSignature: signature,
+      aliasOf: undefined
     }
   }
 
-  // remove the outer parenthesis, for example "((re: number) => Complex<number>)" returns "(re: number) => Complex<number>"
-  function stripParenthesis(text: string) : string {
-    return text.startsWith('(') && text.endsWith(')')
-      ? text.substring(1, text.length - 1)
-      : text
+  const inner = findBlockContents(signature, '<', '>').innerText.trim()
+  const [aliasOfWithQuotes, innerSignature] = split(inner, ',').map(trim)
+  return {
+    innerSignature,
+    aliasOf: aliasOfWithQuotes.substring(1, aliasOfWithQuotes.length - 1) // remove double quotes
   }
 }
 
+// remove the outer parenthesis, for example "((re: number) => Complex<number>)" returns "(re: number) => Complex<number>"
+function stripParenthesis(text: string) : string {
+  return text.startsWith('(') && text.endsWith(')')
+    ? text.substring(1, text.length - 1)
+    : text
+}
+
 function findBlockContents(text: string, blockStart: string, blockEnd: string, startIndex = 0) : { start: number, end: number, innerText: string } | undefined {
   let i = startIndex
 
@@ -143,21 +160,45 @@ function findBlockContents(text: string, blockStart: string, blockEnd: string, s
   }
 }
 
+/**
+ * Given a string, generate a string source for a regexp that will match
+ * exactly the given string.
+ * Uses the fact that the only characters that need to be escaped in
+ * a character class are \, ], and ^
+ */
+function regexpQuote(s: string) {
+  const special = '\\]^'
+  let re = ''
+  for (const char of s) {
+    if (special.includes(char)) re += `\\${char}`
+    else re += `[${char}]`
+  }
+  return re
+}
+
 /**
  * Split a string by a delimiter, but ignore all occurrences of the delimiter
  * that are inside bracket pairs <> () [] {}
  */
-export function split(text: string, delimiter: string) : string[] {
+export function split(
+     text: string, delimiter: string | RegExp, pieces = 0): string[] {
+  const delim: RegExp = typeof delimiter === 'string'
+     ? new RegExp(regexpQuote(delimiter), 'y')
+     : new RegExp(delimiter.source, 'y')
   const parts: string[] = []
 
   let i = 0
+  let n = 1
   let start = 0
-  while (i < text.length) {
+  while (i < text.length && (pieces === 0 || n < pieces)) {
     i = skipBrackets(text, i)
 
-    if (matchSubString(text, delimiter, i)) {
+    delim.lastIndex = i
+    const result = delim.exec(text)
+    if (result) {
       parts.push(text.substring(start, i))
-      i += delimiter.length
+      n += 1
+      i += result[0].length
       start = i
     }
 

src/generic/relational.ts

@@ -1,5 +1,7 @@
 import {Dependencies, Signature} from '../interfaces/type.js'
+import {$reflect} from '../interfaces/type.js'
 
 export const unequal =
    <T>(dep: Dependencies<'equal', T>): Signature<'unequal', T> =>
    (x, y) => !dep.equal(x, y)
+$reflect!([unequal])

src/numbers/native.ts

@@ -1,2 +1,4 @@
 export * from './type.js'
 export * from './arithmetic.js'
+export * from './predicate.js'
+export * from './relational.js'

src/numbers/predicate.ts

@@ -1,4 +1,7 @@
 import type {Signature} from '../interfaces/type.js'
+import {$reflect} from '../interfaces/type.js'
 
-export const isReal:   Signature<'isReal',   number> = (a) => true
-export const isSquare: Signature<'isSquare', number> = (a) => a >= 0
+export const isReal =   (): Signature<'isReal',   number> => (a) => true
+export const isSquare = (): Signature<'isSquare', number> => (a) => a >= 0
+
+$reflect!([isReal, isSquare])

src/numbers/relational.ts

@@ -1,5 +1,6 @@
 import {configDependency} from '../core/Config.js'
 import {Signature} from '../interfaces/type.js'
+import {$reflect} from '../interfaces/type.js'
 
 const DBL_EPSILON = Number.EPSILON || 2.2204460492503130808472633361816E-16
 
@@ -19,3 +20,4 @@ export const equal =
 
       return false
    }
+$reflect!([equal])

src/numbers/type.ts

@@ -1,4 +1,5 @@
 import type { Signature } from '../interfaces/type.js'
+import {$reflect} from '../interfaces/type.js'
 
 export const number_type = {
    name: 'number', // just until we have reflection to tell us
@@ -20,7 +21,9 @@ declare module "../interfaces/type" {
 }
 
 // I don't like the redundancy of repeating 'zero'; any way to eliminate that?
-export const zero: Signature<'zero', number> = (a) => 0
-export const one:  Signature<'one',  number> = (a) => 1
-export const nan:  Signature<'nan',  number> = (a) => NaN
-export const re:   Signature<'re',   number> = (a) => a
+export const zero = (): Signature<'zero', number> => (a) => 0
+export const one =  (): Signature<'one',  number> => (a) => 1
+export const nan =  (): Signature<'nan',  number> => (a) => NaN
+export const re =   (): Signature<'re',   number> => (a) => a
+
+$reflect!([zero, one, nan, re])