Func<T,TResult> F# snippets (#7611)

Author: albert-du

samples/snippets/fsharp/VS_Snippets_CLR_System/system.Func~2/fs/Delegate.fs

@@ -0,0 +1,15 @@
+module Delegate
+
+// <Snippet1>
+type ConvertMethod = delegate of string -> string
+
+let uppercaseString (inputString: string) =
+    inputString.ToUpper()
+    
+// Instantiate delegate to reference uppercaseString function
+let convertMeth = ConvertMethod uppercaseString
+let name = "Dakota"
+
+// Use delegate instance to call uppercaseString function
+printfn $"{convertMeth.Invoke name}"
+// </Snippet1>

samples/snippets/fsharp/VS_Snippets_CLR_System/system.Func~2/fs/Example.fs

@@ -0,0 +1,26 @@
+module Example
+
+// <Snippet5>
+open System
+open System.Linq
+
+// Declare a Func variable and assign a lambda expression to the
+// variable. The function takes a string and converts it to uppercase.
+let selector = Func<string, string>(fun str -> str.ToUpper())
+
+// Create a list of strings.
+let words = [ "orange"; "apple"; "Article"; "elephant" ]
+
+// Query the list and select strings according to the selector function.
+let aWords = words.Select selector
+
+// Output the results to the console.
+for word in aWords do
+    printfn $"{word}"
+
+// This code example produces the following output:
+//     ORANGE
+//     APPLE
+//     ARTICLE
+//     ELEPHANT
+// </Snippet5>

samples/snippets/fsharp/VS_Snippets_CLR_System/system.Func~2/fs/Func2_1.fs

@@ -0,0 +1,18 @@
+module Func2_1
+
+// <Snippet2>
+open System
+
+let uppercaseString (inputString: string) =
+    inputString.ToUpper()
+
+// Instantiate delegate to reference uppercaseString function
+let convertMethod = Func<string, string> uppercaseString
+let name = "Dakota"
+
+// Use delegate instance to call uppercaseString function
+printfn $"{convertMethod.Invoke name}"
+
+// This code example produces the following output:
+//    DAKOTA
+// </Snippet2>

samples/snippets/fsharp/VS_Snippets_CLR_System/system.Func~2/fs/Lambda.fs

@@ -0,0 +1,13 @@
+module Lambda
+
+// <Snippet4>
+open System
+
+let convert = Func<string, string>(fun s -> s.ToUpper())
+
+let name = "Dakota"
+printfn $"{convert.Invoke name}"
+
+// This code example produces the following output:
+//    DAKOTA
+// </Snippet4>

samples/snippets/fsharp/VS_Snippets_CLR_System/system.Func~2/fs/fs.fsproj

@@ -0,0 +1,12 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="Delegate.fs" />
+    <Compile Include="Func2_1.fs" />
+    <Compile Include="Lambda.fs" />
+    <Compile Include="Example.fs" />
+  </ItemGroup>
+</Project>

xml/System/Func`2.xml

@@ -91,20 +91,23 @@
  When you use the <xref:System.Func%602> delegate, you do not have to explicitly define a delegate that encapsulates a method with a single parameter. For example, the following code explicitly declares a delegate named `ConvertMethod` and assigns a reference to the `UppercaseString` method to its delegate instance.  
  
  :::code language="csharp" source="~/samples/snippets/csharp/VS_Snippets_CLR_System/system.Func~2/cs/Delegate.cs" interactive="try-dotnet" id="Snippet1":::
+ :::code language="fsharp" source="~/samples/snippets/fsharp/VS_Snippets_CLR_System/system.Func~2/fs/Delegate.fs" id="Snippet1":::
  :::code language="vb" source="~/samples/snippets/visualbasic/VS_Snippets_CLR_System/system.Func~2/vb/Delegate.vb" id="Snippet1":::
   
  The following example simplifies this code by instantiating the <xref:System.Func%602> delegate instead of explicitly defining a new delegate and assigning a named method to it.  
   
  :::code language="csharp" source="~/samples/snippets/csharp/VS_Snippets_CLR_System/system.Func~2/cs/Func2_1.cs" interactive="try-dotnet-method" id="Snippet2":::
+ :::code language="fsharp" source="~/samples/snippets/fsharp/VS_Snippets_CLR_System/system.Func~2/fs/Func2_1.fs" id="Snippet2":::
  :::code language="vb" source="~/samples/snippets/visualbasic/VS_Snippets_CLR_System/system.Func~2/vb/Func2_1.vb" id="Snippet2":::
   
  You can also use the <xref:System.Func%602> delegate with anonymous methods in C#, as the following example illustrates. (For an introduction to anonymous methods, see [Anonymous Methods](/dotnet/csharp/programming-guide/statements-expressions-operators/anonymous-methods).)  
  
  :::code language="csharp" source="~/samples/snippets/csharp/VS_Snippets_CLR_System/system.Func~2/cs/Anon.cs" interactive="try-dotnet-method" id="Snippet3":::
   
- You can also assign a lambda expression to a <xref:System.Func%602> delegate, as the following example illustrates. (For an introduction to lambda expressions, see [Lambda Expressions](/dotnet/visual-basic/programming-guide/language-features/procedures/lambda-expressions) and [Lambda Expressions](/dotnet/csharp/programming-guide/statements-expressions-operators/lambda-expressions).)  
+ You can also assign a lambda expression to a <xref:System.Func%602> delegate, as the following example illustrates. (For an introduction to lambda expressions, see [Lambda Expressions (VB)](/dotnet/visual-basic/programming-guide/language-features/procedures/lambda-expressions), [Lambda Expressions (C#)](/dotnet/csharp/programming-guide/statements-expressions-operators/lambda-expressions) and [Lambda Expressions (F#)](/dotnet/fsharp/language-reference/functions/lambda-expressions-the-fun-keyword).)  
   
  :::code language="csharp" source="~/samples/snippets/csharp/VS_Snippets_CLR_System/system.Func~2/cs/Lambda.cs" interactive="try-dotnet-method" id="Snippet4":::
+ :::code language="fsharp" source="~/samples/snippets/fsharp/VS_Snippets_CLR_System/system.Func~2/fs/Lambda.fs" id="Snippet4":::
  :::code language="vb" source="~/samples/snippets/visualbasic/VS_Snippets_CLR_System/system.Func~2/vb/Lambda.vb" id="Snippet4":::
  
  The underlying type of a lambda expression is one of the generic `Func` delegates. This makes it possible to pass a lambda expression as a parameter without explicitly assigning it to a delegate. In particular, because many methods of types in the <xref:System.Linq> namespace have <xref:System.Func%602> parameters, you can pass these methods a lambda expression without explicitly instantiating a <xref:System.Func%602> delegate.  
@@ -115,14 +118,17 @@
  The following example demonstrates how to declare and use a <xref:System.Func%602> delegate. This example declares a <xref:System.Func%602> variable and assigns it a lambda expression that converts the characters in a string to uppercase. The delegate that encapsulates this method is subsequently passed to the <xref:System.Linq.Enumerable.Select%2A?displayProperty=nameWithType> method to change the strings in an array of strings to uppercase.  
 
  :::code language="csharp" source="~/samples/snippets/csharp/VS_Snippets_CLR_System/system.Func~2/cs/Example.cs" interactive="try-dotnet-method" id="Snippet5":::
+ :::code language="fsharp" source="~/samples/snippets/fsharp/VS_Snippets_CLR_System/system.Func~2/fs/Example.fs" id="Snippet5":::
  :::code language="vb" source="~/samples/snippets/visualbasic/VS_Snippets_CLR_System/system.Func~2/vb/Example.vb" id="Snippet5":::
  :::code language="cpp" source="~/samples/snippets/cpp/VS_Snippets_CLR_System/system.Func~2/cpp/Example.cpp" id="Snippet6":::
   
  ]]></format>
     </remarks>
     <related type="Article" href="/dotnet/csharp/programming-guide/statements-expressions-operators/lambda-expressions">Lambda Expressions (C# Programming Guide)</related>
+    <related type="Article" href="/dotnet/fsharp/language-reference/functions/lambda-expressions-the-fun-keyword">Lambda Expressions: The fun Keyword (F#)</related>
     <related type="Article" href="/dotnet/visual-basic/programming-guide/language-features/procedures/lambda-expressions">Lambda Expressions (Visual Basic)</related>
     <related type="Article" href="/dotnet/csharp/programming-guide/delegates/">Delegates (C# Programming Guide)</related>
+    <related type="Article" href="/dotnet/fsharp/language-reference/delegates/">Delegates (F#)</related>
     <related type="Article" href="/dotnet/visual-basic/programming-guide/language-features/delegates/">Delegates (Visual Basic)</related>
   </Docs>
 </Type>