31 lines
1 KiB
JavaScript
31 lines
1 KiB
JavaScript
import { fnType, prodType } from "../type_registry.js";
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import { Function, Type } from "../metacircular.js";
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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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// Given two types A and B, create the type (A × B).
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export const makeProductType = (leftType, rightType) => {
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const pType = prodType(leftType, rightType);
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const leftFnType = fnType({in: pType, out: leftType});
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const rightFnType = fnType({in: pType, out: rightType});
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const constructorBoundType = fnType({in: rightType, out: pType});
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const constructorType = fnType({in: leftType , out: constructorBoundType});
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return {l:[
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{i: pType, t: Type},
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{i: getLeft , t: leftFnType},
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{i: getRight , t: rightFnType},
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{i: leftFnType , t: Function},
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{i: rightFnType, t: Function},
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{i: constructor , t: constructorType},
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{i: constructorType , t: Function},
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{i: constructorBoundType, t: Function},
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]};
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};
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