feat: add rnix LSP support

closes #10

adapted code from
#16
thanks to @JamieMagee

package.json

@@ -66,7 +66,22 @@
         "language": "nix",
         "path": "./snippets.json"
       }
-    ]
+    ],
+    "configuration": {
+      "title": "NixIDE",
+      "properties": {
+        "nix.serverPath": {
+          "type": "string",
+          "default": "",
+          "description": "Location of the rnix language server. By default rnix from $PATH is used (if enableLanguageServer is true.)"
+        },
+        "nix.enableLanguageServer": {
+          "type": "boolean",
+          "default": false,
+          "description": "Setting this would disable nix-instantiate and nixpkgs-fmt"
+        }
+      }
+    }
   },
   "devDependencies": {
     "@commitlint/cli": "^11.0.0",
@@ -94,5 +109,8 @@
     "release": "standard-version && git push --follow-tags",
     "pkg-release": "vsce publish && ovsx publish --pat $OVS_PAT",
     "lint": "eslint --ext ts src"
+  },
+  "dependencies": {
+    "vscode-languageclient": "^7.0.0"
   }
 }

src/client.ts

@@ -0,0 +1,53 @@
+// from PR of https://github.com/nix-community/vscode-nix-ide/pull/16/
+
+import { env, ExtensionContext, Uri, window, workspace } from "vscode";
+import {
+  Executable,
+  LanguageClient,
+  LanguageClientOptions,
+  ServerOptions,
+} from "vscode-languageclient";
+import { config, UriMessageItem } from "./configuration";
+
+let client: LanguageClient;
+
+export async function activate(context: ExtensionContext): Promise<void> {
+  if (config.serverPath === undefined || config.serverPath === "") {
+    const selection = await window.showErrorMessage<UriMessageItem>(
+      "Unable to find Nix language server",
+      {
+        title: "Install language server",
+        uri: Uri.parse("https://github.com/nix-community/rnix-lsp"),
+      }
+    );
+    if (selection?.uri !== undefined) {
+      await env.openExternal(selection?.uri);
+      return;
+    }
+  }
+  const serverExecutable: Executable = {
+    command: config.serverPath,
+  };
+  const serverOptions: ServerOptions = serverExecutable;
+
+  const nixDocumentSelector: { scheme: string; language: string }[] = [
+    { scheme: "file", language: "nix" },
+    { scheme: "untitled", language: "nix" },
+  ];
+
+  const clientOptions: LanguageClientOptions = {
+    documentSelector: nixDocumentSelector,
+    synchronize: {
+      fileEvents: workspace.createFileSystemWatcher("**/*.nix"),
+    },
+    outputChannel: window.createOutputChannel("Nix"),
+  };
+
+  client = new LanguageClient("nix", "Nix", serverOptions, clientOptions);
+  client.registerProposedFeatures();
+  context.subscriptions.push(client.start());
+}
+
+export function deactivate(): Thenable<void> | undefined {
+  return client ? client.stop() : undefined;
+}

src/configuration.ts

@@ -0,0 +1,28 @@
+import * as vscode from "vscode";
+
+import { MessageItem, Uri } from "vscode";
+
+export interface UriMessageItem extends MessageItem {
+  uri: Uri;
+}
+
+export class Config {
+  readonly rootSection = "nix";
+
+  private get cfg(): vscode.WorkspaceConfiguration {
+    return vscode.workspace.getConfiguration(this.rootSection);
+  }
+
+  private get<T>(path: string): T {
+    return this.cfg.get<T>(path)!;
+  }
+
+  get serverPath(): string {
+    return this.get<string>("serverPath");
+  }
+
+  get LSPEnabled(): boolean {
+    return this.get<boolean>("enableLanguageServer");
+  }
+}
+export const config = new Config();

src/extension.ts

@@ -2,23 +2,36 @@ import * as vscode from "vscode";
 import { ExtensionContext } from "vscode";
 import { formattingProviders } from "./formatter";
 import { startLinting } from "./linter";
+import { config } from "./configuration";
+import * as client from "./client";
 
 /**
  * Activate this extension.
  *
- * Format with nixpkgs-format
- * validate with nix-instantiate
+ * If LSP is enabled
+ *    then support IDE features with {@link https://github.com/nix-community/rnix-lsp|rnix-lsp}
+ * Else
+ *    Format with nixpkgs-format
+ *    validate with nix-instantiate
  *
  * @param context The context for this extension
  * @return A promise for the initialization
  */
 export async function activate(context: ExtensionContext): Promise<void> {
-  await startLinting(context);
+  if (config.LSPEnabled) {
+    await client.activate(context);
+  } else {
+    await startLinting(context);
+    const subs = [
+      vscode.languages.registerDocumentFormattingEditProvider,
+      vscode.languages.registerDocumentRangeFormattingEditProvider,
+    ].map((func) => func("nix", formattingProviders));
+    context.subscriptions.concat(subs);
+  }
+}
 
-  const subs = [
-    vscode.languages.registerDocumentFormattingEditProvider,
-    vscode.languages.registerDocumentRangeFormattingEditProvider,
-  ].map((func) => func("nix", formattingProviders));
-
-  context.subscriptions.concat(subs);
-};
+export async function deactivate(): Promise<void> {
+  if (config.LSPEnabled) {
+    await client.deactivate();
+  }
+}

yarn.lock

@@ -2065,6 +2065,13 @@ loud-rejection@^1.0.0:
     currently-unhandled "^0.4.1"
     signal-exit "^3.0.0"
 
+lru-cache@^6.0.0:
+  version "6.0.0"
+  resolved "https://registry.yarnpkg.com/lru-cache/-/lru-cache-6.0.0.tgz#6d6fe6570ebd96aaf90fcad1dafa3b2566db3a94"
+  integrity sha512-Jo6dJ04CmSjuznwJSS3pUeWmd/H0ffTlkXXgwZi+eq1UCmqQwCh+eLsYOYCwY991i2Fah4h1BEMCx4qThGbsiA==
+  dependencies:
+    yallist "^4.0.0"
+
 map-obj@^1.0.0, map-obj@^1.0.1:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/map-obj/-/map-obj-1.0.1.tgz#d933ceb9205d82bdcf4886f6742bdc2b4dea146d"
@@ -2884,6 +2891,13 @@ semver@^6.0.0:
   resolved "https://registry.yarnpkg.com/semver/-/semver-6.3.0.tgz#ee0a64c8af5e8ceea67687b133761e1becbd1d3d"
   integrity sha512-b39TBaTSfV6yBrapU89p5fKekE2m/NwnDocOVruQFS1/veMgdzuPcnOM34M6CwxW8jH/lxEa5rBoDeUwu5HHTw==
 
+semver@^7.3.4:
+  version "7.3.4"
+  resolved "https://registry.yarnpkg.com/semver/-/semver-7.3.4.tgz#27aaa7d2e4ca76452f98d3add093a72c943edc97"
+  integrity sha512-tCfb2WLjqFAtXn4KEdxIhalnRtoKFN7nAwj0B3ZXCbQloV2tq5eDbcTmT68JJD3nRJq24/XgxtQKFIpQdtvmVw==
+  dependencies:
+    lru-cache "^6.0.0"
+
 set-blocking@^2.0.0:
   version "2.0.0"
   resolved "https://registry.yarnpkg.com/set-blocking/-/set-blocking-2.0.0.tgz#045f9782d011ae9a6803ddd382b24392b3d890f7"
@@ -3371,6 +3385,33 @@ vsce@^1.83.0:
     yauzl "^2.3.1"
     yazl "^2.2.2"
 
+[email protected]:
+  version "6.0.0"
+  resolved "https://registry.yarnpkg.com/vscode-jsonrpc/-/vscode-jsonrpc-6.0.0.tgz#108bdb09b4400705176b957ceca9e0880e9b6d4e"
+  integrity sha512-wnJA4BnEjOSyFMvjZdpiOwhSq9uDoK8e/kpRJDTaMYzwlkrhG1fwDIZI94CLsLzlCK5cIbMMtFlJlfR57Lavmg==
+
+vscode-languageclient@^7.0.0:
+  version "7.0.0"
+  resolved "https://registry.yarnpkg.com/vscode-languageclient/-/vscode-languageclient-7.0.0.tgz#b505c22c21ffcf96e167799757fca07a6bad0fb2"
+  integrity sha512-P9AXdAPlsCgslpP9pRxYPqkNYV7Xq8300/aZDpO35j1fJm/ncize8iGswzYlcvFw5DQUx4eVk+KvfXdL0rehNg==
+  dependencies:
+    minimatch "^3.0.4"
+    semver "^7.3.4"
+    vscode-languageserver-protocol "3.16.0"
+
+[email protected]:
+  version "3.16.0"
+  resolved "https://registry.yarnpkg.com/vscode-languageserver-protocol/-/vscode-languageserver-protocol-3.16.0.tgz#34135b61a9091db972188a07d337406a3cdbe821"
+  integrity sha512-sdeUoAawceQdgIfTI+sdcwkiK2KU+2cbEYA0agzM2uqaUy2UpnnGHtWTHVEtS0ES4zHU0eMFRGN+oQgDxlD66A==
+  dependencies:
+    vscode-jsonrpc "6.0.0"
+    vscode-languageserver-types "3.16.0"
+
+[email protected]:
+  version "3.16.0"
+  resolved "https://registry.yarnpkg.com/vscode-languageserver-types/-/vscode-languageserver-types-3.16.0.tgz#ecf393fc121ec6974b2da3efb3155644c514e247"
+  integrity sha512-k8luDIWJWyenLc5ToFQQMaSrqCHiLwyKPHKPQZ5zz21vM+vIVUSvsRpcbiECH4WR88K2XZqc4ScRcZ7nk/jbeA==
+
 vscode-test@^0.4.1:
   version "0.4.3"
   resolved "https://registry.yarnpkg.com/vscode-test/-/vscode-test-0.4.3.tgz#461ebf25fc4bc93d77d982aed556658a2e2b90b8"
@@ -3446,6 +3487,11 @@ y18n@^4.0.0:
   resolved "https://registry.yarnpkg.com/y18n/-/y18n-4.0.0.tgz#95ef94f85ecc81d007c264e190a120f0a3c8566b"
   integrity sha512-r9S/ZyXu/Xu9q1tYlpsLIsa3EeLXXk0VwlxqTcFRfg9EhMW+17kbt9G0NrgCmhGb5vT2hyhJZLfDGx+7+5Uj/w==
 
+yallist@^4.0.0:
+  version "4.0.0"
+  resolved "https://registry.yarnpkg.com/yallist/-/yallist-4.0.0.tgz#9bb92790d9c0effec63be73519e11a35019a3a72"
+  integrity sha512-3wdGidZyq5PB084XLES5TpOSRA3wjXAlIWMhum2kRcv/41Sn2emQ0dycQW4uZXLejwKvg6EsvbdlVL+FYEct7A==
+
 yaml@^1.10.0:
   version "1.10.0"
   resolved "https://registry.yarnpkg.com/yaml/-/yaml-1.10.0.tgz#3b593add944876077d4d683fee01081bd9fff31e"