feat:Statically Resolved Type Parameters (#22)

* feat:added Statically Resolved Type Parameters * feat:contents as a list for better display in HTML --------- Co-authored-by: ⚙︎ Greg <[email protected]>
fsprojects · Oct 23, 2023 · a163d18 · a163d18
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commit a163d18
Showing 1 changed file with 38 additions and 14 deletions.
diff --git a/docs/fsharp-cheatsheet.md b/docs/fsharp-cheatsheet.md
@@ -1,24 +1,25 @@
-This cheatsheet aims to succinctly cover the most important aspects of [F# 6.0](http://research.microsoft.com/en-us/um/cambridge/projects/fsharp/manual/spec.html).
+This cheatsheet aims to succinctly cover the most important aspects of [F# 7.0](http://research.microsoft.com/en-us/um/cambridge/projects/fsharp/manual/spec.html).
 
 The Microsoft [F# Documentation](https://learn.microsoft.com/en-us/dotnet/fsharp/) is complete and authoritative and has received a lot of love in recent years; it's well worth the time investment to read. Only after you've got the lowdown here of course ;)
 
  If you have any comments, corrections, or suggested additions, please open an issue or send a pull request to [https://github.com/fsprojects/fsharp-cheatsheet](https://github.com/fsprojects/fsharp-cheatsheet). Questions are best addressed via the [F# slack](https://fsharp.org/guides/slack) or the [F# discord](https://discord.me/fsharp).
 
 Contents
 --------
-[Comments](#Comments)
-[Strings](#Strings)
-[Basic Types and Literals](#BasicTypesAndLiterals)
-[Functions](#Functions)
-[Pattern Matching](#PatternMatching)
-[Collections](#Collections)
-[Tuples and Records](#TuplesAndRecords)
-[Discriminated Unions](#DiscriminatedUnions)
-[Exceptions](#Exceptions)
-[Classes and Inheritance](#ClassesAndInheritance)
-[Interfaces and Object Expressions](#InterfacesAndObjectExpressions)
-[Active Patterns](#ActivePatterns)
-[Compiler Directives](#CompilerDirectives)
+- [Comments](#Comments)
+- [Strings](#Strings)
+- [Basic Types and Literals](#BasicTypesAndLiterals)
+- [Functions](#Functions)
+- [Pattern Matching](#PatternMatching)
+- [Collections](#Collections)
+- [Tuples and Records](#TuplesAndRecords)
+- [Discriminated Unions](#DiscriminatedUnions)
+- [Statically Resolved Type Parameters](#StaticallyResolvedTypeParameters)
+- [Exceptions](#Exceptions)
+- [Classes and Inheritance](#ClassesAndInheritance)
+- [Interfaces and Object Expressions](#InterfacesAndObjectExpressions)
+- [Active Patterns](#ActivePatterns)
+- [Compiler Directives](#CompilerDirectives)
 
 <a name="Comments"></a>Comments
 --------
@@ -338,6 +339,29 @@ Single-case discriminated unions are often used to create type-safe abstractions
     // Use pattern matching to deconstruct single-case DU
     let (Order id) = orderId
 
+<a name="#StaticallyResolvedTypeParameters"></a>Statically Resolved Type Parameters
+--------------------
+A *statically resolved type parameter* is a type parameter that is replaced with an actual type at compile time instead of at run time. They are primarily useful in conjunction with member constraints.
+
+    let inline add x y = x + y
+    let integerAdd = add 1 2
+    let floatAdd = add 1.0f 2.0f // without `inline` on `add` function, this would cause a type error
+
+####
+
+    type RequestA = { Id: string; StringValue: string }
+    type RequestB = { Id: string; IntValue: int }
+
+    let requestA : RequestA = { Id = "A"; StringValue = "Value" }
+    let requestB : RequestB = { Id = "B"; IntValue = 42 }
+
+    let inline getIdOfRequest<'t when 't : (member Id: string)> (x: 't) = x.Id
+
+    let idA = getIdOfRequest requestA // "A"
+    let idB = getIdOfRequest requestB // "B"
+
+See [Statically Resolved Type Parameters (MS Learn)](https://learn.microsoft.com/en-us/dotnet/fsharp/language-reference/generics/statically-resolved-type-parameters) and [Constraints (MS Learn)](https://learn.microsoft.com/en-us/dotnet/fsharp/language-reference/generics/constraints) for more examples.
+
 <a name="Exceptions"></a>Exceptions
 ----------