writers: add writeNim and writeNimBin

This adds convenience writers for self-contained Nim programs.
Those are compiled into very small binaries.

Test with: `nix build .#pkgs.tests.writers.{bin,simple,wrapping}.nim`

pkgs/build-support/writers/scripts.nix

@@ -651,6 +651,53 @@ rec {
   */
   writeHaskellBin = name: writeHaskell "/bin/${name}";
 
+  /**
+    writeNim takes a name, an attrset with an optional Nim compiler, and some
+    Nim source code, returning an executable.
+
+    # Examples
+    :::{.example}
+    ## `pkgs.writers.writeNim` usage example
+
+    ```nix
+      writeNim "hello-nim" { nim = pkgs.nim2; } ''
+        echo "hello nim"
+      '';
+    ```
+    :::
+  */
+  writeNim =
+    name:
+    {
+      makeWrapperArgs ? [ ],
+      nim ? pkgs.nim2,
+      nimCompileOptions ? { },
+      strip ? true,
+    }:
+    let
+      nimCompileCmdArgs = lib.cli.toGNUCommandLineShell { optionValueSeparator = ":"; } (
+        {
+          d = "release";
+          nimcache = ".";
+        }
+        // nimCompileOptions
+      );
+    in
+    makeBinWriter {
+      compileScript = ''
+        cp $contentPath tmp.nim
+        ${lib.getExe nim} compile ${nimCompileCmdArgs} tmp.nim
+        mv tmp $out
+      '';
+      inherit makeWrapperArgs strip;
+    } name;
+
+  /**
+    writeNimBin takes the same arguments as writeNim but outputs a directory
+    (like writeScriptBin)
+  */
+  writeNimBin = name: writeNim "/bin/${name}";
+
   /**
     Like writeScript but the first line is a shebang to nu
 

pkgs/build-support/writers/test.nix

@@ -31,6 +31,8 @@ let
     writeJSBin
     writeJSON
     writeLua
+    writeNim
+    writeNimBin
     writeNu
     writePerl
     writePerlBin
@@ -109,6 +111,10 @@ recurseIntoAttrs {
         _ -> print "fail"
     '');
 
+    nim = expectSuccessBin (writeNimBin "test-writers-nim-bin" { } ''
+      echo "success"
+    '');
+
     js = expectSuccessBin (writeJSBin "test-writers-js-bin" { libraries = [ nodePackages.semver ]; } ''
       var semver = require('semver');
 
@@ -191,6 +197,10 @@ recurseIntoAttrs {
       end
     '');
 
+    nim = expectSuccess (writeNim "test-writers-nim" { } ''
+      echo "success"
+    '');
+
     nu = expectSuccess (writeNu "test-writers-nushell" ''
       echo "success"
     '');
@@ -411,6 +421,23 @@ recurseIntoAttrs {
         ''
     );
 
+    nim = expectSuccess (
+      writeNim "test-writers-wrapping-nim"
+        {
+          makeWrapperArgs = [
+            "--set"
+            "ThaigerSprint"
+            "Thailand"
+          ];
+        }
+        ''
+          import os
+
+          if getEnv("ThaigerSprint") == "Thailand":
+            echo "success"
+        ''
+    );
+
     python = expectSuccess (
       writePython3 "test-writers-wrapping-python"
         {