progress

generics/generics.js

@@ -8,7 +8,8 @@ import { pretty, zip } from "../util.js";
 //     makeGeneric(a => fnType({in: a, out: fnType({in: a, out: Bool})}))
 export const makeGeneric = callback => {
   // type variables to make available:
-  const typeVars = ['a', 'b', 'c', 'd', 'e'].map(letter => ({
+  const typeVars = ['a', 'b', 'c', 'd', 'e'].map(
+    letter => ({
       symbol: Symbol(letter), 
       params: [],
     }));
@@ -28,6 +29,7 @@ export const occurring = (type, typeVars) => {
   return new Set(type.params.flatMap(p => [...occurring(p, typeVars)]));
 }
 
+// Merge 2 substitution-mappings, uni-directional.
 const mergeOneWay = (m1, m2) => {
   const m1copy = new Map(m1);
   const m2copy = new Map(m2);
@@ -41,6 +43,7 @@ const mergeOneWay = (m1, m2) => {
   return [true, m1copy, m2copy, new Set()]; // stable
 }
 
+// Merge 2 substitution-mappings, bi-directional.
 export const mergeTwoWay = (m1, m2) => {
   // check for conflicts:
   for (const [typeVar, actual] of m1) {
@@ -69,10 +72,12 @@ export const unify = (
   {typeVars: formalTypeVars, type: formalType},
   {typeVars: actualTypeVars, type: actualType},
 ) => {
-  // console.log("unify", {formalTypeVars, formalType, actualTypeVars, actualType});
+  // console.log("unify",  pretty({formalTypeVars, formalType, actualTypeVars, actualType}));
+  
   if (formalTypeVars.has(formalType)) {
     // simplest case: formalType is a type paramater
     //   => substitute with actualType
+    // console.log("assign actual to formal");
     return {
       substitutions: new Map([[formalType, actualType]]),
       typeVars: new Set([
@@ -84,6 +89,7 @@ export const unify = (
   }
   if (actualTypeVars.has(actualType)) {
     // same as above, but in the other direction
+    // console.log("assign formal to actual");
     return {
       substitutions: new Map([[actualType, formalType]]),
       typeVars: new Set([
@@ -98,6 +104,7 @@ export const unify = (
     throw new Error(`cannot unify ${pretty(formalType.symbol)} and ${pretty(actualType.symbol)}`);
   }
   else {
+    // console.log("symbols match - unify recursively", formalType.symbol);
     const unifiedParams = zip(formalType.params, actualType.params).map(([formalParam, actualParam]) => unify({typeVars: formalTypeVars, type: formalParam}, {typeVars: actualTypeVars, type: actualParam}));
     const [unifiedSubstitusions, deleted] = unifiedParams.reduce(([substitutionsSoFar, deletedSoFar], cur) => {
       // console.log('merging', substitutionsSoFar, cur.substitutions);
@@ -124,6 +131,12 @@ export const substitute = (type, substitutions) => {
     // type IS a type var to be substituted:
     return substitutions.get(type);
   }
+  if (type.params.length === 0) {
+    // Attention: there's a reason why we have this special case.
+    // Types are compared by object ID, so we don't want to create a new object for a type that takes no type parameters (then the newly create type would differ).
+    // Should fix this some day.
+    return type;
+  }
   return {
     symbol: type.symbol,
     params: type.params.map(p => substitute(p, substitutions)),

generics/generics.test.js

@@ -1,41 +1,40 @@
 import { Bool, Int } from "../primitives/types.js";
-import { lsType } from "../structures/types.js";
+import { fnType, lsType } from "../structures/types.js";
-import { fnType } from "../structures/function.js";
 import { assign, makeGeneric, unify } from "./generics.js";
 import { pretty } from "../util.js";
 
 // a -> Int
-const a_to_Int = makeGeneric(a => fnType({in: a, out: Int}));
+const a_to_Int = makeGeneric(a => fnType(a)(Int));
 // Bool -> Int
-const Bool_to_Int = makeGeneric(() => fnType({in: lsType(Bool), out: Int}));
+const Bool_to_Int = makeGeneric(() => fnType(lsType(Bool))(Int));
 console.log("should be: [Bool] -> Int")
 console.log(pretty(unify(a_to_Int, Bool_to_Int)));
 
 // (a -> a) -> b
-const fnType2 = makeGeneric((a,b) => fnType({in: fnType({in: a, out: a}), out: b}));
+const fnType2 = makeGeneric((a,b) => fnType(fnType(a)(a))(b));
 // (Bool -> Bool) -> a
-const fnType3 = makeGeneric(a => fnType({in: fnType({in: Bool, out: Bool}), out: a}));
+const fnType3 = makeGeneric(a => fnType(fnType(Bool)(Bool))(a));
 console.log("should be: (Bool -> Bool) -> a");
 console.log(pretty(unify(fnType2, fnType3)));
 
 // (a -> b) -> [a] -> [b]
 const mapFnType = makeGeneric((a,b) =>
-  fnType({
+  fnType
-    in: fnType({in: a, out: b}),
+    (fnType(a)(b))
-    out: fnType({in: lsType(a), out: lsType(b)}),
+    (fnType(lsType(a))(lsType(b))))
-  }));
 // a -> a
 const idFnType = makeGeneric(a =>
-  fnType({in: a, out: a}));
+  fnType(a)(a));
 console.log("should be: [a] -> [a]");
 console.log(pretty(assign(mapFnType, idFnType)));
 
 // (a -> Int) -> [a] -> a
 const weirdFnType = makeGeneric(a =>
-  fnType({
+  fnType
-    in: fnType({in: a, out: Int}),
+    (fnType(a)(Int))
-    out: fnType({in: lsType(a), out: a}),
+    (fnType
-  }));
+      (lsType(a))
+      (a)))
 // we call this function with parameter of type (b -> b) ...
 // giving these substitutions:
 //    a := b

lib/point.js

@@ -1,4 +1,4 @@
-import { Type } from "../type.js";
+import { Type } from "../primitives/types.js";
 import { typedFnType } from "../structures/types.js"
 import { Double } from "../primitives/types.js";
 

main.js

@@ -3,7 +3,8 @@ import { ModulePoint } from "./lib/point.js";
 import { DefaultMap, pretty, prettyT } from './util.js';
 import { symbolFunction } from './structures/types.js';
 import { ModuleStd } from './stdlib.js';
-import { Type } from './type.js';
+import { Type } from "./primitives/types.js";
+import { assign, makeGeneric, unify } from './generics/generics.js';
 
 class Context {
   constructor(mod) {
@@ -11,14 +12,14 @@ class Context {
     this.types = new DefaultMap(() => new Set()); // instance to type
     this.instances = new DefaultMap(() => new Set()); // type to instance
 
-    this.functionsFrom = new DefaultMap(() => new Set()); // type to outgoing function
-    this.functionsTo = new DefaultMap(() => new Set()); // type to incoming function
-
     for (const {i, t} of mod.l) {
       this.types.getdefault(i, true).add(t);
       this.instances.getdefault(t, true).add(i);
     }
 
+    this.functionsFrom = new DefaultMap(() => new Set()); // type to outgoing function
+    this.functionsTo = new DefaultMap(() => new Set()); // type to incoming function
+
     for (const t of this.instances.m.keys()) {
       if (t.symbol === symbolFunction) {
         // 't' is a function signature
@@ -28,6 +29,24 @@ class Context {
         }
       }
     }
+
+    // this.typeVarAssigns = new Map();
+
+    // for (const t of this.instances.m.keys()) {
+    //   if (t.typeVars) {
+    //     for (const t2 of this.instances.m.keys()) {
+    //       const genericT2 = (t2.typeVars === undefined)
+    //         ? makeGeneric(() => t2)
+    //         : t2;
+    //       try {
+    //         const unification = unify(t, t2);
+    //         console.log(unification);
+    //       } catch (e) {
+    //         // skip
+    //       }
+    //     }
+    //   }
+    // }
   }
 
   addToCtx({i, t}) {
@@ -38,13 +57,13 @@ class Context {
   }
 }
 
+
 let ctx = new Context({l:[
   ...ModuleStd.l,
   ...ModulePoint.l,
 ]});
 
 
-
 const prettyIT = ({i, t}) => ({
   strI: isType(i) ? prettyT(i) : pretty(i),
   strT: prettyT(t),
@@ -74,7 +93,11 @@ async function topPrompt() {
     ],
   });
   if (action === "list all types") {
-    await listAllTypes();
+    await listInstances(Type);
+    // await listAllTypes();
+  }
+  if (action === "list all functions") {
+    await listAllFunctions();
   }
   if (action === "list all") {
     await listAllInstances();
@@ -82,22 +105,46 @@ async function topPrompt() {
   return topPrompt();
 }
 
-async function listAllTypes() {
+// async function listAllTypes() {
+//   const choice = await select({
+//     message: "select type:",
+//     choices: [
+//       "(go back)",
+//       ...[...ctx.instances.m.keys()].map(t => ({
+//         value: t,
+//         name: prettyT(t),
+//       })),
+//     ]
+//   });
+//   if (choice === "(go back)") {
+//     return;
+//   }
+//   await typeOptions(choice);
+//   return listAllTypes();
+// }
+
+async function listAllFunctions() {
   const choice = await select({
-    message: "select type:",
+    message: "select function:",
     choices: [
       "(go back)",
-      ...[...ctx.instances.m.keys()].map(t => ({
+      ...[...ctx.types.m.entries()]
-        value: t,
+        .filter(([i, types]) => {
-        name: prettyT(t),
+          for (const type of types) {
-      })),
+            if (type.symbol === symbolFunction)
-    ]
+              return true;
+          }
+          return false;
+        })
+        .flatMap(toChoices),
+    ],
   });
   if (choice === "(go back)") {
     return;
   }
-  await typeOptions(choice);
+  const {i, t} = choice;
-  return listAllTypes();
+  await functionOptions(i, t);
+  return listAllFunctions();
 }
 
 async function typeOptions(t) {
@@ -106,8 +153,9 @@ async function typeOptions(t) {
     choices: [
       "(go back)",
       "list instances",
-      "list outgoing functions",
+      // "list outgoing functions",
-      "list incoming functions",
+      // "list incoming functions",
+      "print raw",
       "treat as instance",
     ],
   });
@@ -117,6 +165,9 @@ async function typeOptions(t) {
   else if (choice === "list instances") {
     await listInstances(t);
   }
+  else if (choice === "print raw") {
+    console.log(pretty(t));
+  }
   else if (choice === "treat as instance") {
     await instanceOptions(t, Type)
   }

primitives/bool.js

@@ -1,5 +1,5 @@
 import { fnType, typedFnType } from "../structures/types.js";
-import { Type } from "../type.js";
+import { Type } from "./types.js";
 import { Bool } from "./types.js";
 
 const eqBool = x => y => x === y;

primitives/byte.js

@@ -1,5 +1,5 @@
 import { typedFnType } from "../structures/types.js";
-import { Type } from "../type.js";
+import { Type } from "./types.js";
 import {Byte, Bool} from "./types.js";
 
 const eqByte = x => y => x === y;

primitives/char.js

@@ -1,5 +1,5 @@
 import { typedFnType } from "../structures/types.js";
-import { Type } from "../type.js";
+import { Type } from "./types.js";
 import {Char, Bool} from "./types.js";
 
 const eq = x => y => x === y;

primitives/double.js

@@ -1,5 +1,5 @@
 import { typedFnType } from "../structures/types.js";
-import { Type } from "../type.js";
+import { Type } from "./types.js";
 import {Bool, Double} from "./types.js";
 
 export const addDouble = x => y => x + y;

primitives/int.js

@@ -1,5 +1,5 @@
 import { typedFnType } from "../structures/types.js";
-import { Type } from "../type.js";
+import { Type } from "./types.js";
 
 import {Bool, Int} from "./types.js";
 

primitives/types.js

@@ -5,3 +5,5 @@ export const Bool   = { symbol: Symbol('Bool')  , params: [] };
 export const Double = { symbol: Symbol('Double'), params: [] };
 export const Byte   = { symbol: Symbol('Byte')  , params: [] };
 export const Char   = { symbol: Symbol('Char')  , params: [] };
+
+export const Type = { symbol: Symbol('Type'), params: [] };

structures/function.js

@@ -1,4 +1,4 @@
-import { Type } from "../type.js";
+import { Type } from "../primitives/types.js";
 import { typedFnType } from "./types.js";
 import { fnType } from "./types.js";
 

structures/list.js

@@ -1,5 +1,5 @@
 import { fnType, typedFnType } from "./types.js";
-import { Type } from "../type.js";
+import { Type } from "../primitives/types.js";
 import { Int } from "../primitives/types.js";
 import { makeGeneric } from "../generics/generics.js";
 import { lsType } from "./types.js";

structures/product.js

@@ -1,5 +1,5 @@
 import { makeGeneric } from "../generics/generics.js";
-import { Type } from "../type.js";
+import { Type } from "../primitives/types.js";
 import { typedFnType } from "./types.js";
 import { prodType } from "./types.js";
 

structures/sum.js

@@ -1,15 +1,15 @@
 import { prodType } from "./types.js";
-import { Type } from "../type.js";
+import { Type } from "../primitives/types.js";
 import { typedFnType } from "./types.js";
 import { makeGeneric } from "../generics/generics.js";
 import { sumType } from "./types.js";
 
-const constructorLeft  = left  => ({variant: "L", value: left });
+export const constructorLeft  = left  => ({variant: "L", value: left });
-const constructorRight = right => ({variant: "R", value: right});
+export const constructorRight = right => ({variant: "R", value: right});
 
 // signature:
 //   sum-type -> (leftType -> resultType, rightType -> resultType) -> resultType
-const match = sum => handlers => sum.variant === "L"
+export const match = sum => handlers => sum.variant === "L"
   ? handlers.left(sum.value)
   : handlers.right(sum.value);
 

structures/types.js

@@ -1,6 +1,6 @@
 // to break up dependency cycles, type constructors are defined in their own JS module
 
-import { Type } from "../type.js";
+import { Type } from "../primitives/types.js";
 import { DefaultMap } from "../util.js";
 
 

type.js

@@ -1,11 +1,7 @@
-import { Bool } from "./primitives/types.js";
+import { Bool, Type } from "./primitives/types.js";
 import { typedFnType } from "./structures/types.js";
 import { deepEqual } from "./util.js";
 
-// TODO: 'Type' (and its instances) are itself instances of (String,[Type]) (=the product type of String and list of Type)
-//   so is 'Type' just an alias for (String, [Type])
-export const Type = { symbol: Symbol('Type'), params: [] };
-
 export const getSymbol = type => type.symbol;
 export const getParams = type => type.params;
 

typeclasses/eq.js

@@ -1,5 +1,5 @@
 import { makeGeneric } from "../generics/generics";
-import { Type } from "../type";
+import { Type } from "../primitives/types";
 import { typedFnType } from "../structures/types";
 import { Bool, Byte, Char, Double, Int } from "../primitives/types";
 import { deepEqual } from "../util";

typeclasses/num.js

@@ -1,7 +1,7 @@
 import { makeGeneric } from "../generics/generics.js";
 import { addDouble, mulDouble } from "../primitives/double.js";
 import { addInt, mulInt } from "../primitives/int.js";
-import { Type } from "../type.js";
+import { Type } from "../primitives/types.js";
 import { typedFnType, typedFnType2 } from "../structures/types.js";
 import { Double, Int } from "../primitives/types.js";
 import { numDictType } from "./num_type.js";
@@ -10,14 +10,15 @@ export const getAdd  = numDict => numDict.add;
 export const getMul  = numDict => numDict.mul;
 
 // getAdd and getMul have same (generic) type:
+//   NumDict a -> a -> a -> a
 const [getAddMulFnType, typesOfFns] = typedFnType2(fnType =>
-  makeGeneric(a => fnType({
+  makeGeneric(a => 
-    in: numDictType(a),
+    fnType
-    out: fnType({
+      (numDictType(a))
-      in: a,
+      (fnType
-      out: fnType({in: a, out: a}),
+        (a)
-    }),
+        (fnType(a)(a))
-  })));
+      )));
 
 export const ModuleNum = {l:[
   ...typedFnType(numDictType, fnType => fnType({in: Type, out: Type})),

typeclasses/num.test.js

@@ -1,29 +1,28 @@
 import { assign } from "../generics/generics.js";
 import { makeGeneric } from "../generics/generics.js";
-import { fnType } from "../structures/function.js";
 import { Double, Int } from "../primitives/types.js";
+import { fnType } from "../structures/types.js";
+import { pretty } from "../util.js";
 import { getMul, NumInstances } from "./num.js";
 import { numDictType } from "./num_type.js";
 
 const square = numDict => x => getMul(numDict)(x)(x);
 
+// NumDict a -> a -> a
 const squareFnType = makeGeneric(a => 
-  fnType({
+  fnType
-    in: numDictType(a),
+    (numDictType(a))
-    out: fnType({
+    (fnType(a)(a))
-      in: a,
+  );
-      out: a,
-    }),
-  }));
 
 console.log("should be: Int -> Int");
-console.log(assign(squareFnType, makeGeneric(() => numDictType(Int))));
+console.log(pretty(assign(squareFnType, makeGeneric(() => numDictType(Int)))));
 
 console.log("should be: Double -> Double");
-console.log(assign(squareFnType, makeGeneric(() => numDictType(Double))));
+console.log(pretty(assign(squareFnType, makeGeneric(() => numDictType(Double)))));
 
 // to call 'square' we need:
+//   - the type of our argument (=Int)
 //   - access to a mapping from types to their typeclass instantiation
-//   - to know that our argument is 'Int'
 console.log("");
 console.log(square(NumInstances.get(Int))(42n)); // 1764n

typeclasses/resolve.js

@@ -1 +0,0 @@
-// const resolveTypeClass = (mapping, )

typed.js

@@ -1,5 +1,5 @@
 import { typedFnType } from "./structures/types.js";
-import { Type } from "./type.js";
+import { Type } from "./primitives/types.js";
 
 // Everything is (implicitly) typed by the Any type.
 export const Any = { symbol: Symbol('Any'), params: [] };

util.js

@@ -1,3 +1,6 @@
+import { inspect } from 'node:util';
+import { symbolFunction, symbolList, symbolProduct, symbolSum } from './structures/types.js';
+
 // re-inventing the wheel:
 export function deepEqual(a, b) {
   if (a === b) return true; // <- shallow equality and primitives
@@ -45,18 +48,18 @@ export class DefaultMap {
   }
 }
 
-
-import { inspect } from 'node:util';
-import { symbolFunction, symbolList, symbolProduct, symbolSum } from './structures/types.js';
-
 export function pretty(obj) {
   return inspect(obj, {colors: true, depth: null});
 }
 
+// Pretty print type
 export function prettyT(type) {
   if (type.typeVars) {
+    if (type.typeVars.size > 0) {
       return `∀${[...type.typeVars].map(prettyT).join(", ")}: ${prettyT(type.type)}`;
     }
+    return prettyT(type.type);
+  }
   if (type.symbol === symbolFunction) {
     return `${prettyT(type.params[0])} -> ${prettyT(type.params[1])}`;
   }