Fix 46

AUTHORS

@@ -9,3 +9,5 @@ Sven Slootweg <[email protected]> (https://github.com/joepie91/)
 yy0931 (https://github.com/yy0931)
 Rene Saarsoo <[email protected]> (https://github.com/nene/)
 Lionel Rowe (https://github.com/lionel-rowe/)
+Joe Andaverde (https://github.com/dynajoe)
+Michael Klaus <[email protected]> (https://github.com/qades78)

README.md

@@ -55,6 +55,14 @@ of all of the rules in the Outline view.
 
 ![Outline](/images/outline.png)
 
+## Live Preview
+
+Live edit and test your Grammars, optionally starting at the rule under cursor.
+
+### Tips
+
+Name your grammar like this for optimal experience: grammar_name.language_extension.peggy. Where language_extension is the extension of the language you're parsing. This will provide syntax highlighting if you have a matching language server installed.
+
 ## Contributing
 
 Feel free to contribute to this extension [here](https://github.com/peggyjs/code-peggy-language).

client/index.ts

@@ -0,0 +1,10 @@
+import { activate as activateClient, deactivate } from "./client";
+import { ExtensionContext } from "vscode";
+import { activate as activateLivePreview } from "./preview";
+
+export function activate(context: ExtensionContext): void {
+  activateLivePreview(context);
+  activateClient(context);
+}
+
+export { deactivate };

client/preview.ts

@@ -0,0 +1,176 @@
+import * as path from "path";
+import * as peggy from "peggy";
+import * as util from "node-inspect-extracted";
+import {
+  ExtensionContext,
+  OutputChannel,
+  Uri,
+  ViewColumn,
+  commands,
+  window,
+  workspace,
+} from "vscode";
+import { MemFS } from "../vendor/vscode-extension-samples/fileSystemProvider";
+import { debounce } from "../common/debounce";
+
+const PEGGY_INPUT_SCHEME = "peggyjsin";
+
+interface GrammarConfig {
+  name: string;
+  key: string;
+  start_rule: string | undefined;
+  grammar_uri: Uri;
+  input_uri: Uri;
+  timeout?: NodeJS.Timeout;
+  grammar_text?: string;
+  parser?: any;
+}
+
+async function executeAndDisplayResults(
+  output: OutputChannel,
+  config: GrammarConfig
+): Promise<void> {
+  output.show(true);
+  let out = `// ${config.name} ${config.start_rule ? `(${config.start_rule})` : ""}\n`;
+
+  try {
+    const [grammar_document, input_document] = [
+      await workspace.openTextDocument(config.grammar_uri),
+      await workspace.openTextDocument(config.input_uri),
+    ];
+
+    // Never leave it dirty; it's saved in memory anyway.
+    // Don't bother to wait for the promise.
+    input_document.save();
+    const grammar_text = grammar_document.getText();
+
+    if (grammar_text !== config.grammar_text) {
+      config.parser = peggy.generate(
+        grammar_text,
+        config.start_rule
+          ? {
+              allowedStartRules: [config.start_rule],
+            }
+          : undefined
+      );
+      config.grammar_text = grammar_text;
+    }
+
+    const input = input_document.getText();
+    const result = config.parser.parse(
+      input,
+      config.start_rule ? { startRule: config.start_rule } : undefined
+    );
+
+    out += util.inspect(result, {
+      depth: Infinity,
+      colors: false,
+      maxArrayLength: Infinity,
+      maxStringLength: Infinity,
+      breakLength: 40,
+      sorted: true,
+    });
+    out += "\n";
+  } catch (error) {
+    out += error.toString();
+    out += "\n";
+  }
+  // Replace once, since addLine causes issues with trailing spaces.
+  output.replace(out);
+}
+
+const debounceExecution = debounce(executeAndDisplayResults, 300);
+
+export function activate(context: ExtensionContext): void {
+  const peggy_output = window.createOutputChannel("Peggy Live", "javascript");
+  const memory_fs = new MemFS();
+  const grammars = new Map<string, GrammarConfig>();
+
+  function grammarNameFromUri(uri: Uri): string {
+    return path
+      .basename(uri.fsPath)
+      .replace(/\.(pegjs|peggy)$/, "")
+      .replace(/^[(][^)]+[)]__/, "");
+  }
+
+  function trackGrammar(
+    grammar_document_uri: Uri,
+    start_rule?: string
+  ): GrammarConfig {
+    const grammar_name = grammarNameFromUri(grammar_document_uri);
+    const key = `${grammar_name}:${start_rule || "*"}`;
+
+    const input_document_uri = start_rule
+      ? Uri.parse(`${PEGGY_INPUT_SCHEME}:/(${start_rule})__${grammar_name}`)
+      : Uri.parse(`${PEGGY_INPUT_SCHEME}:/${grammar_name}`);
+
+    const is_input_document_open = workspace.textDocuments.find(
+      d => d.uri === input_document_uri
+    );
+
+    if (!is_input_document_open) {
+      workspace.fs.writeFile(input_document_uri, Buffer.from("")).then(() => {
+        window.showTextDocument(input_document_uri, {
+          viewColumn: ViewColumn.Beside,
+          preserveFocus: true,
+        });
+      });
+    }
+    const config = {
+      name: grammar_name,
+      key,
+      start_rule,
+      grammar_uri: grammar_document_uri,
+      input_uri: input_document_uri,
+    };
+    grammars.set(key, config);
+    return config;
+  }
+
+  const documents_changed = workspace.onDidChangeTextDocument(async e => {
+    const document_uri_string = e.document.uri.toString();
+
+    for (const config of grammars.values()) {
+      if (
+        config.grammar_uri.toString() === document_uri_string
+        || config.input_uri.toString() === document_uri_string
+      ) {
+        await executeAndDisplayResults(peggy_output, config);
+      }
+    }
+  });
+
+  const documents_closed = workspace.onDidCloseTextDocument(e => {
+    const to_remove = [...grammars.values()].filter(
+      config => config.grammar_uri === e.uri || config.input_uri === e.uri
+    );
+
+    to_remove.forEach(config => {
+      grammars.delete(config.key);
+    });
+  });
+
+  context.subscriptions.push(
+    documents_changed,
+    documents_closed,
+    peggy_output,
+    commands.registerTextEditorCommand("editor.peggyLive", editor => {
+      const grammar_config = trackGrammar(editor.document.uri);
+      debounceExecution(peggy_output, grammar_config);
+    }),
+    commands.registerTextEditorCommand("editor.peggyLiveFromRule", editor => {
+      const word_range = editor.document.getWordRangeAtPosition(
+        editor.selection.start,
+        /[_$a-zA-Z\xA0-\uFFFF][_$a-zA-Z0-9\xA0-\uFFFF]*/
+      );
+
+      if (word_range !== null) {
+        const rule_name = editor.document.getText(word_range);
+        const grammar_config = trackGrammar(editor.document.uri, rule_name);
+
+        debounceExecution(peggy_output, grammar_config);
+      }
+    })
+  );
+  workspace.registerFileSystemProvider(PEGGY_INPUT_SCHEME, memory_fs);
+}

eslint.config.mjs

@@ -7,6 +7,7 @@ export default [
   {
     ignores: [
       "out/**",
+      "vendor/**",
     ],
   },
   ...commonjs,

package.json

@@ -11,6 +11,7 @@
   },
   "homepage": "https://github.com/peggyjs/code-peggy-language",
   "categories": [
+    "Debuggers",
     "Programming Languages",
     "Snippets"
   ],
@@ -91,6 +92,32 @@
         "language": "peggy",
         "path": "./snippets/snippets.json"
       }
+    ],
+    "menus": {
+      "editor/context": [
+        {
+          "command": "editor.peggyLive",
+          "group": "3_preview",
+          "when": "editorLangId == peggy"
+        },
+        {
+          "command": "editor.peggyLiveFromRule",
+          "group": "3_preview",
+          "when": "editorLangId == peggy"
+        }
+      ]
+    },
+    "commands": [
+      {
+        "command": "editor.peggyLive",
+        "title": "Peggy Live Preview",
+        "category": "preview"
+      },
+      {
+        "command": "editor.peggyLiveFromRule",
+        "title": "Peggy Live from rule under cursor",
+        "category": "preview"
+      }
     ]
   },
   "scripts": {
@@ -120,6 +147,7 @@
     "webpack-cli": "^5.1.4"
   },
   "dependencies": {
+    "node-inspect-extracted": "3.0.2",
     "peggy": "^4.1.1",
     "source-map-generator": "0.8.0",
     "vscode-languageclient": "^9.0.1",