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