Added dotnet fsharp

runtimes/default.nix

@@ -54,4 +54,5 @@ args: {
     "gnat-ada" = import ./gnat-ada.nix args;
     "rust" = import ./rust.nix args;
     "dotnet-sdk-csharp" = import ./dotnet-sdk-csharp.nix args;
+    "dotnet-sdk-fsharp" = import ./dotnet-sdk-fsharp.nix args;
 }

runtimes/dotnet-sdk-fsharp.nix

@@ -0,0 +1,80 @@
+{pkgs, piston, ...}:
+let
+    nugetPkg = pkgs.stdenv.mkDerivation {
+        pname = "fsharp-nuget-packages";
+        version = pkgs.dotnet-sdk.version;
+
+        dontUnpack = true;
+        dontBuild = true;
+        dontConfigure = true;
+        dontFixup = true;
+        dontPatch = true;
+
+        buildInputs = [
+            pkgs.dotnet-sdk
+        ];
+        installPhase = ''
+            mkdir $out
+            cd $out
+            export HOME=$PWD
+            dotnet new console -lang F# -o fs_cache_application
+            rm -rf fs_cache_application
+        '';
+    };
+    pkg = pkgs.dotnet-sdk;
+in piston.mkRuntime {
+    language = "fsharp";
+    version = pkg.version;
+    runtime = "dotnet-sdk";
+
+    aliases = [
+        "fsharp.net"
+        "fs"
+        "f#"
+        "fs.net"
+        "f#.net"
+        "fsharp-dotnet"
+        "fs-dotnet"
+        "f#-dotnet"
+        "dotnet-fsharp"
+        "dotnet-fs"
+        "dotnet-fs"
+    ];
+
+    compile = ''
+        export HOME=${nugetPkg}
+        ${pkg}/dotnet build --help > /dev/null # Supress welcome message
+        first_file=$1
+        shift
+        rename 's/$/\.fs/' "$@" # Add .fs extension
+        ${pkg}/dotnet new console -lang F# -o . --no-restore
+        mv $first_file Program.fs
+        ${pkg}/dotnet restore --source ${nugetPkg}/.nuget/packages
+        ${pkg}/dotnet build --no-restore
+    '';
+
+    run = ''
+        export HOME=${nugetPkg}
+        shift
+        ${pkg}/dotnet bin/Debug/net6.0/$(basename $(realpath .)).dll "$@"
+    '';
+
+    tests = [
+        (piston.mkTest {
+            files = {
+                "test.fs" = ''
+                    open System
+
+                    [<EntryPoint>]
+                    let main argv =
+                        Console.WriteLine argv[0]
+                        0
+                '';
+            };
+            args = ["OK"];
+            stdin = "";
+            packages = [];
+            main = "test.fs";
+        })
+    ];
+}