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get rid of some stuff

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This commit is contained in:
Joeri Exelmans 2025-05-23 14:45:35 +02:00
parent 2333abe70f
commit 3d72f4d416
6 changed files with 38 additions and 86 deletions
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41
lib/generics/generics.js
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@ -1,10 +1,7 @@
import { inspect } from "node:util";
import { inspectType, makeTypeConstructor } from "../meta/type_constructor.js";
import { inspectType } from "../meta/type_constructor.js";
import { getSymbol } from "../primitives/type.js";
import { isTypeVar, TYPE_VARS, UNBOUND_SYMBOLS } from "../primitives/typevars.js";
import { symbolFunction } from "../structures/type_constructors.js";
import { prettyT } from '../util/pretty.js';
import { reduceUnification, unifyLL } from "./low_level.js";
// helper for creating generic types
// for instance, the type:
@ -35,18 +32,6 @@ const _occurring = stack => type => {
// Get set of type variables in type.
export const occurring = _occurring([]);
export class UnifyError extends Error {}
export class NotAFunctionError extends Error {}
export const unify = (fType, aType) => {
[fType, aType] = recomputeTypeVars([fType, aType]);
const unification = unifyLL(fType, aType);
const substitutions = reduceUnification(unification);
const uType = substitute(fType, // or aType, doesn't matter here
substitutions);
return recomputeTypeVars([uType])[0];
};
export const substitute = (type, substitutions, stack=[]) => {
// console.log('substitute...', {type, substitutions, stack});
const found = substitutions.get(getSymbol(type));
@ -67,30 +52,6 @@ export const substitute = (type, substitutions, stack=[]) => {
};
};
export const assignFn = (funType, paramType, skip=0) => {
// Precondition
if (getSymbol(funType) !== symbolFunction) {
throw new NotAFunctionError(`${prettyT(funType)} is not a function type!`);
}
// Step 1: Very important: Function and parameter type may have overlapping type variables, so we recompute them to make them non-overlapping:
const [funType1, paramType1] = recomputeTypeVars([funType, paramType]);
// Step 2: Get input and output type of function
const [inType1, outType1] = funType1.params.map(p => p(funType1));
// Step 3: Unify parameter type with input type
const unifInType1 = unifyLL(inType1, paramType1);
// Step 4: Substitute typevars in output type
const substInType1 = reduceUnification(unifInType1);
const reducedOutType1 = substitute(outType1, substInType1);
// Step 5: 'Normalize' output type
const [outType] = recomputeTypeVars([reducedOutType1], skip);
return outType;
}
// Ensures that no type variables overlap
export const recomputeTypeVars = (types, skip=0) => {
return recomputeTypeVarsWithInverse(types, skip)[0];