38 lines
1.0 KiB
C#
38 lines
1.0 KiB
C#
namespace Immutable {
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using System;
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public interface Option<out T> {
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U Match_<U>(Func<T, U> some, Func<U> none);
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}
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public static class Option {
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public static Option<T> Some<T>(T value) => new Types.Some<T>(value);
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public static Option<T> None<T>() => new Types.None<T>();
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private static class Types {
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public class Some<T> : Option<T> {
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public readonly T value;
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public Some(T value) { this.value = value; }
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public U Match_<U>(Func<T, U> Some, Func<U> None) => Some(value);
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}
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public class None<T> : Option<T> {
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public None() { }
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public U Match_<U>(Func<T, U> Some, Func<U> None) => None();
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}
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}
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}
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public static class OptionExtensionMethods {
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public static Option<T> Some<T>(this T value) => Option.Some<T>(value);
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public static U Match<T, U>(this Option<T> o, Func<T, U> some, Func<U> none)
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=> o.Match_(some, none);
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public static U Match<T, U>(this Option<T> o, Func<T, U> some, U none)
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=> o.Match_(some, () => none);
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}
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} |