neovim: add csharp treesitter and lsp

modules/user/neovim.nix

@@ -25,6 +25,7 @@
 
       (nvim-treesitter.withPlugins (p: with p; [
         tree-sitter-comment
+        tree-sitter-c-sharp
         # tree-sitter-javascript
         tree-sitter-jsdoc
         tree-sitter-nix
@@ -127,6 +128,7 @@
       };
     };
     "eslint.enable" = true;
+    "omnisharp.path" = "${pkgs.omnisharp-roslyn}/bin/omnisharp";
     "rust-analyzer.lens.enable" = false;
     "rust-analyzer.inlayHints.enable" = false;
     "rust-analyzer.serverPath" = pkgs.rust-analyzer + "/bin/rust-analyzer";

overlays/tree-sitter.nix

@@ -0,0 +1,31 @@
+# experiment!
+self: super:
+let
+  lib = super.lib;
+  stdenv = super.stdenv;
+in {
+  tree-sitter = super.tree-sitter.overrideAttrs(o: {
+    passthru = o.passthru // {
+      withPlugins = grammarFn:
+        let
+          grammars = grammarFn o.passthru.builtGrammars;
+        in
+        super.linkFarm "grammars"
+          (map
+            (drv:
+              let
+                name = lib.strings.getName drv;
+              in
+              {
+                name =
+                  (lib.strings.replaceStrings ["-"] ["_"]
+                    (lib.strings.removePrefix "tree-sitter-"
+                      (lib.strings.removeSuffix "-grammar" name)))
+                  + stdenv.hostPlatform.extensions.sharedLibrary;
+                path = "${drv}/parser";
+              }
+            )
+            grammars);
+    };
+  });
+}