Created
July 20, 2015 23:54
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Gross C# functional stuff
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using System; | |
using System.Collections.Generic; | |
using System.Linq; | |
using static System.Console; | |
using static System.Math; | |
using static Functional; | |
public static class Functional | |
{ | |
public static Func<X, Z> Compose<X, Y, Z>(Func<Y, Z> g, Func<X, Y> f) => x => g(f(x)); | |
public static Func<X, Func<Y, Z>> Curry<X, Y, Z>(Func<X, Y, Z> f) => x => y => f(x, y); | |
public static Func<X, Func<X, X>> CurryUniform<X>(Func<X, X, X> f) => x => y => f(x, y); | |
public static Func<IEnumerable<X>, IEnumerable<Y>> Map<X, Y>(Func<X, Y> f) => xs => xs.Select(x => f(x)); | |
public static Func<A, Func<IEnumerable<X>, A>> Foldl<X, A>(Func<A, Func<X, A>> f) => a => xs => xs.Aggregate(a, (a2, x2) => f(a2)(x2)); | |
} | |
public class Program | |
{ | |
public static void Main() | |
{ | |
Func<int, string> f = x => x.ToString(); | |
Func<string, Name> g = x => new Name(x); | |
WriteLine(Compose(g, f)(10)); | |
var pow2 = CurryUniform<double>(Pow)(2.0); | |
WriteLine(pow2(8)); | |
var plus = CurryUniform<int>((x, y) => x + y); | |
var values = new[] { 1, 2, 3 }; | |
var results = Map(Compose(x => x.ToString(), plus(2)))(values); | |
WriteLine(string.Join(", ", results)); | |
var results2 = Compose(Map((int x) => x.ToString()), Map(plus(2)))(values); | |
WriteLine(string.Join(", ", results)); | |
var sum = Foldl(plus)(0)(values); | |
WriteLine(sum); | |
} | |
} | |
public class Name | |
{ | |
public Name(string value) | |
{ | |
Value = value; | |
} | |
public string Value { get; } | |
public override string ToString() => Value; | |
} |
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