From 49716bd884c3963bf9a441c4ed9ae7c16ed538e7 Mon Sep 17 00:00:00 2001
From: Sanchime <sanchime@qq.com>
Date: Wed, 4 May 2022 20:58:08 +0800
Subject: [PATCH] =?UTF-8?q?=E6=9B=B4=E6=96=B0Func=E6=89=A9=E5=B1=95?=
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Content-Type: text/plain; charset=UTF-8
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---
 Sanchime.Functional/Core/Extensions/Either.cs |  2 +-
 Sanchime.Functional/Core/Extensions/Func.cs   | 94 +++++++++++++++++++
 .../Core/Extensions/IEnumerable.cs            |  1 -
 .../Core/Extensions/Identity.cs               |  2 +-
 Sanchime.Functional/Core/Extensions/Option.cs |  2 -
 .../Core/{Eithers => Products}/Either.cs      |  4 +-
 .../Core/{Options => Products}/Option.cs      |  4 +-
 7 files changed, 98 insertions(+), 11 deletions(-)
 create mode 100644 Sanchime.Functional/Core/Extensions/Func.cs
 rename Sanchime.Functional/Core/{Eithers => Products}/Either.cs (96%)
 rename Sanchime.Functional/Core/{Options => Products}/Option.cs (97%)

diff --git a/Sanchime.Functional/Core/Extensions/Either.cs b/Sanchime.Functional/Core/Extensions/Either.cs
index 2817727..508712a 100644
--- a/Sanchime.Functional/Core/Extensions/Either.cs
+++ b/Sanchime.Functional/Core/Extensions/Either.cs
@@ -1,5 +1,5 @@
 using Sanchime.Functional.Core.Products;
-using Sanchime.Functional.Core.Eithers;
+
 namespace Sanchime.Functional.Core.Extensions;
 
 public static class EitherExtension
diff --git a/Sanchime.Functional/Core/Extensions/Func.cs b/Sanchime.Functional/Core/Extensions/Func.cs
new file mode 100644
index 0000000..17a4f22
--- /dev/null
+++ b/Sanchime.Functional/Core/Extensions/Func.cs
@@ -0,0 +1,94 @@
+using Sanchime.Functional.Core.Products;
+namespace Sanchime.Functional.Core.Extensions;
+
+public static class FuncExtension
+{
+    /// <summary>
+    /// 忽略入参<see cref="Unit"/>
+    /// </summary>
+    /// <param name="this"></param>
+    /// <typeparam name="T"></typeparam>
+    /// <returns></returns>
+    public static Func<T> ToNullary<T>(this Func<Unit, T> @this)
+        => () => @this(Unit.Value);
+
+    /// <summary>
+    /// 将两个函数组合
+    /// </summary>
+    /// <param name="left"></param>
+    /// <param name="right"></param>
+    /// <typeparam name="T1"></typeparam>
+    /// <typeparam name="T2"></typeparam>
+    /// <typeparam name="R"></typeparam>
+    /// <returns></returns>
+    public static Func<T1, R> Compose<T1, T2, R>(this Func<T2, R> left, Func<T1, T2> right)
+        => x => left(right(x));
+
+    /// <summary>
+    /// 对谓词取反
+    /// </summary>
+    /// <param name="pred"></param>
+    /// <typeparam name="T"></typeparam>
+    /// <returns></returns>
+    public static Func<T, bool> Negate<T>(this Func<T, bool> pred) 
+        => val => !pred(val);
+
+    #region 函子
+    public static Func<R> Map<T, R>(this Func<T> @this, Func<T,R> mapping)
+        => () => mapping(@this());
+
+    public static Func<T1, T2, R> Map<T1, T2, T3, R>(this Func<T1, T2, T3> @this, Func<T3, R> mapping)
+        => (t1, t2) => mapping(@this(t1, t2));
+
+    #endregion
+
+    #region 单子
+    public static Func<R> Bind<T, R>(this Func<T> @this, Func<T, Func<R>> binding)
+        => () => binding(@this()).Invoke();
+
+    #endregion
+
+    #region 应用子
+
+    public static Func<T2, R> Apply<T1, T2, R>(this Func<T1, T2, R> @this, T1 t1)
+        => (t2) => @this(t1, t2);
+
+    public static Func<T2, T3, R> Apply<T1, T2, T3, R>(this Func<T1, T2, T3, R> @this, T1 t1)
+        => (t2, t3) => @this(t1, t2, t3);
+
+    public static Func<T2, T3, T4, R> Apply<T1, T2, T3, T4, R>(this Func<T1, T2, T3, T4, R> @this, T1 t1)
+        => (t2, t3, t4) => @this(t1, t2, t3, t4);
+
+    public static Func<T2, T3, T4, T5, R> Apply<T1, T2, T3, T4, T5, R>(this Func<T1, T2, T3, T4, T5, R> @this, T1 t1)
+        => (t2, t3, t4, t5) => @this(t1, t2, t3, t4, t5);
+
+    public static Func<T2, T3, T4, T5, T6, R> Apply<T1, T2, T3, T4, T5, T6, R>(this Func<T1, T2, T3, T4, T5, T6, R> @this, T1 t1)
+        => (t2, t3, t4, t5, t6) => @this(t1, t2, t3, t4, t5, t6);
+
+    public static Func<T2, T3, T4, T5, T6, T7, R> Apply<T1, T2, T3, T4, T5, T6, T7, R>(this Func<T1, T2, T3, T4, T5, T6, T7, R> @this, T1 t1)
+        => (t2, t3, t4, t5, t6, t7) => @this(t1, t2, t3, t4, t5, t6, t7);
+
+    public static Func<T2, T3, T4, T5, T6, T7, T8, R> Apply<T1, T2, T3, T4, T5, T6, T7, T8, R>(this Func<T1, T2, T3, T4, T5, T6, T7, T8, R> @this, T1 t1)
+        => (t2, t3, t4, t5, t6, t7, t8) => @this(t1, t2, t3, t4, t5, t6, t7, t8);
+
+    public static Func<T2, T3, T4, T5, T6, T7, T8, T9, R> Apply<T1, T2, T3, T4, T5, T6, T7, T8, T9, R>(this Func<T1, T2, T3, T4, T5, T6, T7, T8, T9, R> @this, T1 t1)
+        => (t2, t3, t4, t5, t6, t7, t8, t9) => @this(t1, t2, t3, t4, t5, t6, t7, t8, t9);
+
+
+    #endregion
+
+    #region Linq
+
+    public static Func<R> Select<T, R>(this Func<T> @this, Func<T,R> mapping)
+        => @this.Map(mapping);
+
+    public static Func<P> SelectMany<T, R, P>(this Func<T> @this, Func<T,Func<R>> binding, Func<T, R, P> project)
+        => () => 
+        {
+            var t = @this();
+            var r = binding(t).Invoke();
+            return project(t, r);
+        };
+
+    #endregion
+}
\ No newline at end of file
diff --git a/Sanchime.Functional/Core/Extensions/IEnumerable.cs b/Sanchime.Functional/Core/Extensions/IEnumerable.cs
index e757fa2..1bf9a10 100644
--- a/Sanchime.Functional/Core/Extensions/IEnumerable.cs
+++ b/Sanchime.Functional/Core/Extensions/IEnumerable.cs
@@ -1,5 +1,4 @@
 using System.Collections.Immutable;
-using Sanchime.Functional.Core.Options;
 using Sanchime.Functional.Core.Products;
 
 namespace Sanchime.Functional.Core.Extensions;
diff --git a/Sanchime.Functional/Core/Extensions/Identity.cs b/Sanchime.Functional/Core/Extensions/Identity.cs
index dc7901d..df70ba3 100644
--- a/Sanchime.Functional/Core/Extensions/Identity.cs
+++ b/Sanchime.Functional/Core/Extensions/Identity.cs
@@ -8,5 +8,5 @@ public static class IdentityExtension
         => () => mapping(@this());
 
     public static Identity<R> Bind<T, R>(this Identity<T> @this, Func<T, Identity<R>> binding)
-        => binding(@this()).Invoke();
+        => () => binding(@this()).Invoke();
 }
diff --git a/Sanchime.Functional/Core/Extensions/Option.cs b/Sanchime.Functional/Core/Extensions/Option.cs
index d44b6cb..0c838b1 100644
--- a/Sanchime.Functional/Core/Extensions/Option.cs
+++ b/Sanchime.Functional/Core/Extensions/Option.cs
@@ -1,5 +1,3 @@
-using System;
-using Sanchime.Functional.Core.Options;
 using Sanchime.Functional.Core.Products;
 
 namespace Sanchime.Functional.Core.Extensions;
diff --git a/Sanchime.Functional/Core/Eithers/Either.cs b/Sanchime.Functional/Core/Products/Either.cs
similarity index 96%
rename from Sanchime.Functional/Core/Eithers/Either.cs
rename to Sanchime.Functional/Core/Products/Either.cs
index 8de5b80..669ea9c 100644
--- a/Sanchime.Functional/Core/Eithers/Either.cs
+++ b/Sanchime.Functional/Core/Products/Either.cs
@@ -1,6 +1,4 @@
-using Sanchime.Functional.Core.Products;
-
-namespace Sanchime.Functional.Core.Eithers;
+namespace Sanchime.Functional.Core.Products;
 
 public static class Either
 {
diff --git a/Sanchime.Functional/Core/Options/Option.cs b/Sanchime.Functional/Core/Products/Option.cs
similarity index 97%
rename from Sanchime.Functional/Core/Options/Option.cs
rename to Sanchime.Functional/Core/Products/Option.cs
index d3cd9a9..e33f560 100644
--- a/Sanchime.Functional/Core/Options/Option.cs
+++ b/Sanchime.Functional/Core/Products/Option.cs
@@ -1,6 +1,4 @@
-using Sanchime.Functional.Core.Products;
-
-namespace Sanchime.Functional.Core.Options;
+namespace Sanchime.Functional.Core.Products;
 
 /// <summary>
 /// <see cref="Option"/>的<see cref="None"/>状态