51 lines
1.3 KiB
JavaScript
51 lines
1.3 KiB
JavaScript
import { makeGeneric } from "../generics/generics.js";
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import { Type } from "../metacircular.js";
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import { DefaultMap } from "../util.js";
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import { typedFnType } from "./function.js";
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const symbolProduct = Symbol("Product");
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const productTypeRegistry = new DefaultMap(leftType => new DefaultMap(rightType => ({
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symbol: symbolProduct,
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params: [leftType, rightType],
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})));
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// type constructor
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export const prodType = leftType => rightType => productTypeRegistry.getdefault(leftType, true).getdefault(rightType, true);
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// In JS, all products are encoded in the same way:
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const constructor = left => right => ({left, right});
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const getLeft = product => product.left;
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const getRight = product => product.right;
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export const ModuleProduct = {l: [
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// binary type constructor
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// Type -> Type -> Type
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...typedFnType(prodType, fnType => fnType
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(Type)
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(fnType
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(Type)
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(Type)
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)
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),
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// a -> b -> (a, b)
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...typedFnType(constructor, fnType => makeGeneric((a, b) => fnType
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(a)
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(fnType
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(b)
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(prodType(a)(b))
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)
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)),
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// (a, b) -> a
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...typedFnType(getLeft, fnType => makeGeneric((a, b) => fnType
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(prodType(a)(b))
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(a)
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)),
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// (a, b) -> b
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...typedFnType(getRight, fnType => makeGeneric((a, b) => fnType
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(prodType(a)(b))
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(b)
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)),
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]};
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