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turn one example into a test + fix bug in type variable substition function

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This commit is contained in:
Joeri Exelmans 2025-05-08 17:30:42 +02:00
parent a664ddac8a
commit 35d682429b
4 changed files with 148 additions and 102 deletions
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0
examples/parser.js
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97
examples/recursive_types.js
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import { compareTypes } from "../lib/compare/type.js";
import { makeGeneric, substitute, unify } from "../lib/generics/generics.js";
import { Double, Int, Unit } from "../lib/primitives/primitive_types.js";
import { TYPE_VARS } from "../lib/primitives/typevars.js";
import { fnType, lsType, prodType, sumType, setType } from "../lib/structures/type_constructors.js";
import { prettyT } from "../lib/util/pretty.js";
Error.stackTraceLimit = Infinity;
// some recursive types:
const listOfSetOfSelf = lsType(self => setType(_ => self));
const makeLinkedList = elementType => sumType
(self => prodType
(_ => elementType)
(_ => self))
(_ => Unit);
const linkedListOfInt = makeLinkedList(Int);
const linkedListOfDouble = makeLinkedList(Double);
// some generic types
const genericFunction = makeGeneric((a,b) => fnType(_ => a)(_ => b));
const genericLinkedList = makeGeneric(a => makeLinkedList(a));
// pretty-printing of recursive types:
console.log(prettyT(listOfSetOfSelf)); // #0[{#0}]
console.log(prettyT(linkedListOfInt)); // #0((Int ⨯ #0) + Unit)
console.log(prettyT(genericFunction)); // (a -> b)
console.log(prettyT(genericLinkedList)); // #0((a ⨯ #0) + Unit)
// comparison
console.log(compareTypes(listOfSetOfSelf)(listOfSetOfSelf)) // 0
console.log(compareTypes(linkedListOfInt)(linkedListOfInt)) // 0
console.log(compareTypes(linkedListOfInt)(linkedListOfDouble)) // 1
console.log(compareTypes(linkedListOfDouble)(linkedListOfInt)) // -1
console.log(compareTypes(linkedListOfDouble)(linkedListOfDouble)) // 0
console.log(compareTypes(linkedListOfDouble)(listOfSetOfSelf)) // 1
console.log(compareTypes(listOfSetOfSelf)(linkedListOfDouble)) // -1
const genericList = makeGeneric(a => lsType(_ => a));
const intList = lsType(_ => Int);
console.log(prettyT(genericList)); // [a]
// substitution of type parameters
const substituted = substitute(
genericList,
new Map([
[TYPE_VARS[0], Int],
])
);
console.log(prettyT(substituted)); // [Int]
// substitution (recursive this time)
console.log("recursive substitution")
console.log(prettyT(substitute(
genericLinkedList,
new Map([
[TYPE_VARS[0], Int],
])
))); // #0((Int ⨯ #0) + Unit)
// unification (simple case)
const type = unify(
genericList,
makeGeneric(() => intList));
console.log(prettyT(type)); // [Int]
// unification (recursive case)
console.log("complex case...")
const unified = unify(
genericLinkedList,
makeGeneric(() => linkedListOfInt));
console.log(prettyT(unified)); // #0((Int ⨯ #0) + Unit)
// unification (strange case)
const unified2 = unify(
makeGeneric(() => listOfSetOfSelf),
genericList,
);
console.log(prettyT(unified2)); // #0[{#0}]