languages/kotlin: init (#390)

* merge

* created otter file

merge

* update

merge

* update
merge

* committing flake.lock
merge

* merge

* haskell: added LSP and treesitter

* haskell: default to isMaximal

* haskell: haskell support

* kotlin: LSP and treesitter

* haskell: LSP cmd definition

* haskell: LSP cmd definition (currently broken)

* kotlin: LSP and treesitter working

* removing haskell from kotlin branch

* merge

* merge

* kotlin: capitalisation

* kotlin: implemented formatter

* kotlin: cleanup

* kotlin: formatter and linter both work

* kotlin: cleanup

* kotlin: massive speedup in loadtimes for lsp

* otter: cleanup

* kotlin: changelog entry

* flake.lock: reverting accidental formatting

* kotlin: removed redundant description

* kotlin: fixed typo

* kotlin: using symlinkjoin better

* kotlin: moved wrapper to example

* kotlin: cleaning up and fixing docs render

---------

Co-authored-by: raf <raf@notashelf.dev>

modules/plugins/languages/default.nix

@@ -8,6 +8,7 @@ in {
     ./css.nix
     ./elixir.nix
     ./go.nix
+    ./kotlin.nix
     ./html.nix
     ./java.nix
     ./lua.nix

modules/plugins/languages/kotlin.nix

@@ -0,0 +1,107 @@
+{
+  config,
+  pkgs,
+  lib,
+  ...
+}: let
+  inherit (lib.options) mkEnableOption mkOption literalExpression;
+  inherit (lib.modules) mkIf mkMerge;
+  inherit (lib.meta) getExe;
+  inherit (lib.nvim.languages) diagnosticsToLua;
+  inherit (lib.types) package;
+  inherit (lib.nvim.types) mkGrammarOption diagnostics;
+  inherit (lib.lists) isList;
+  inherit (lib.nvim.lua) expToLua;
+
+  cfg = config.vim.languages.kotlin;
+
+  defaultDiagnosticsProvider = ["ktlint"];
+  diagnosticsProviders = {
+    ktlint = {
+      package = pkgs.ktlint;
+      nullConfig = pkg: ''
+        table.insert(
+          ls_sources,
+          null_ls.builtins.diagnostics.ktlint.with({
+            command = "${getExe pkg}",
+          })
+        )
+      '';
+    };
+  };
+in {
+  options.vim.languages.kotlin = {
+    enable = mkEnableOption "Kotlin/HCL support";
+
+    treesitter = {
+      enable = mkEnableOption "Kotlin treesitter" // {default = config.vim.languages.enableTreesitter;};
+      package = mkGrammarOption pkgs "kotlin";
+    };
+
+    lsp = {
+      enable = mkEnableOption "Kotlin LSP support" // {default = config.vim.languages.enableLSP;};
+
+      package = mkOption {
+        description = "kotlin_language_server package with Kotlin runtime";
+        type = package;
+        example = literalExpression ''
+          pkgs.symlinkJoin {
+              name = "kotlin-language-server-wrapped";
+              paths = [pkgs.kotlin-language-server];
+              nativeBuildInputs = [pkgs.makeWrapper];
+              postBuild = '''
+                wrapProgram $out/bin/kotlin-language-server \
+                  --prefix PATH : ''${pkgs.kotlin}/bin
+              ''';
+            };
+        '';
+        default = pkgs.kotlin-language-server;
+      };
+    };
+
+    extraDiagnostics = {
+      enable = mkEnableOption "extra Kotlin diagnostics" // {default = config.vim.languages.enableExtraDiagnostics;};
+
+      types = diagnostics {
+        langDesc = "Kotlin";
+        inherit diagnosticsProviders;
+        inherit defaultDiagnosticsProvider;
+      };
+    };
+  };
+  config = mkIf cfg.enable (mkMerge [
+    (mkIf cfg.treesitter.enable {
+      vim.treesitter.enable = true;
+      vim.treesitter.grammars = [cfg.treesitter.package];
+    })
+
+    (mkIf cfg.extraDiagnostics.enable {
+      vim.lsp.null-ls.enable = true;
+      vim.lsp.null-ls.sources = diagnosticsToLua {
+        lang = "kotlin";
+        config = cfg.extraDiagnostics.types;
+        inherit diagnosticsProviders;
+      };
+    })
+
+    (mkIf cfg.lsp.enable {
+      vim.lsp.lspconfig.enable = true;
+      vim.lsp.lspconfig.sources.kotlin_language_server = ''
+        lspconfig.kotlin_language_server.setup {
+          capabilities = capabilities,
+          root_dir = lspconfig.util.root_pattern("main.kt", ".git"),
+          on_attach=default_on_attach,
+          init_options = {
+          -- speeds up the startup time for the LSP
+            storagePath = vim.fn.stdpath('state') .. '/kotlin',
+          },
+          cmd = ${
+          if isList cfg.lsp.package
+          then expToLua cfg.lsp.package
+          else ''{"${cfg.lsp.package}/bin/kotlin-language-server"}''
+        },
+        }
+      '';
+    })
+  ]);
+}