repl: integrate experimental repl

doc/api/cli.md

@@ -887,6 +887,14 @@ added: v11.8.0
 
 Use the specified file as a security policy.
 
+### `--experimental-repl`
+
+<!--
+added: REPLACEME
+-->
+
+Use the [experimental REPL][] instead of the default.
+
 ### `--experimental-require-module`
 
 <!-- YAML
@@ -2652,6 +2660,7 @@ one is included in the list below.
 * `--experimental-permission`
 * `--experimental-policy`
 * `--experimental-print-required-tla`
+* `--experimental-repl`
 * `--experimental-require-module`
 * `--experimental-shadow-realm`
 * `--experimental-specifier-resolution`
@@ -3221,6 +3230,7 @@ node --stack-trace-limit=12 -p -e "Error.stackTraceLimit" # prints 12
 [deprecation warnings]: deprecations.md#list-of-deprecated-apis
 [emit_warning]: process.md#processemitwarningwarning-options
 [environment_variables]: #environment-variables
+[experimental REPL]: experimental_repl.md
 [filtering tests by name]: test.md#filtering-tests-by-name
 [jitless]: https://v8.dev/blog/jitless
 [libuv threadpool documentation]: https://docs.libuv.org/en/latest/threadpool.html

doc/api/experimental_repl.md

@@ -0,0 +1,67 @@
+# Experimental REPL
+
+<!--introduced_in=REPLACEME-->
+
+> Stability: 1 - Early Development
+
+<!-- source_link=lib/internal/repl/experimental/index.js -->
+
+Before diving into the details of the experimental REPL, it's essential to
+understand its current development stage. Being an experimental feature, its
+stability cannot be assured. It's accessible solely through the command-line
+argument `--experimental-repl`.
+
+## Overview
+
+The experimental REPL seeks to enhance the existing REPL experience by
+introducing innovative features such as real-time Syntax Highlighting, with
+plans for annotations in future iterations. It's implemented asynchronously,
+utilizing an ECMAScript class for its functionality.
+
+## Key Features
+
+1. **Syntax Highlighting**: Real-time syntax highlighting for improved
+   readability and a more enriched coding environment.
+
+2. **Annotations** (Upcoming): Annotations will allow users to preview the
+   signature of a function.
+
+## Usage
+
+To interact with the experimental REPL, initialize it using the command-line
+argument `--experimental-repl`. However, exercise caution as this feature is
+still experimental and might demonstrate unexpected behavior.
+
+## Runtime
+
+Upon launching the REPL, expect the prompt to follow this format:
+
+```console
+In [1]: 1+1
+Out[1]: 2
+```
+
+Retrieve the output of a specific line using the command `_` followed by the
+line number:
+
+```console
+In [1]: Math.max(10, 100)
+Out[1]: 100
+
+In [2]: _1
+Out[2]: 100
+```
+
+For accessing the output of the last three lines, use `_`, `__`, and `___`
+respectively.
+
+### Known Limitations
+
+Since this REPL is experimental, several limitations are known:
+
+1. Annotations are under development.
+2. Cursor location isn't synchronized after multiple-line text.
+
+If you'd like to propose a solution, feel free to open a
+[pull request](https://github.com/nodejs/node/pulls). If you've identified an
+issue not listed above, open an [issue](https://github.com/nodejs/node/issues).

doc/api/index.md

@@ -29,6 +29,7 @@
 * [DNS](dns.md)
 * [Domain](domain.md)
 * [Errors](errors.md)
+* [Experimental REPL](experimental_repl.md)
 * [Events](events.md)
 * [File system](fs.md)
 * [Globals](globals.md)

doc/api/repl.md

@@ -1,10 +1,13 @@
 # REPL
 
+> This file documents the **stable REPL**. There is a seperate document for
+> the [experimental REPL](./experimental_repl.md)
+
 <!--introduced_in=v0.10.0-->
 
 > Stability: 2 - Stable
 
-<!-- source_link=lib/repl.js -->
+<!-- source_link=lib/internal/repl/stable/index.js -->
 
 The `node:repl` module provides a Read-Eval-Print-Loop (REPL) implementation
 that is available both as a standalone program or includible in other

doc/node.1

@@ -177,6 +177,9 @@ Enable the experimental permission model.
 .It Fl -experimental-policy
 Use the specified file as a security policy.
 .
+.It Fl -experimental-repl
+Use the experimental REPL.
+.
 .It Fl -experimental-shadow-realm
 Use this flag to enable ShadowRealm support.
 .

lib/internal/main/repl.js

@@ -36,9 +36,6 @@ if (process.env.NODE_REPL_EXTERNAL_MODULE) {
   }
 
   require('internal/modules/run_main').runEntryPointWithESMLoader(() => {
-    console.log(`Welcome to Node.js ${process.version}.\n` +
-      'Type ".help" for more information.');
-
     const cliRepl = require('internal/repl');
     cliRepl.createInternalRepl(process.env, (err, repl) => {
       if (err) {

lib/internal/repl.js

@@ -6,13 +6,22 @@ const {
   NumberParseInt,
 } = primordials;
 
-const REPL = require('repl');
-const { kStandaloneREPL } = require('internal/repl/utils');
+const StableREPL = require('internal/repl/stable/index');
+const ExperimentalREPL = require('internal/repl/experimental/index');
+const { kStandaloneREPL } = require('internal/repl/stable/utils');
+const {
+  getOptionValue,
+} = require('internal/options');
+
+const useExperimentalRepl = getOptionValue('--experimental-repl') || false;
+
+module.exports = { __proto__: useExperimentalRepl ? ExperimentalREPL : StableREPL };
+module.exports.createInternalRepl = useExperimentalRepl ? createExperimentalRepl : createStableRepl;
 
-module.exports = { __proto__: REPL };
-module.exports.createInternalRepl = createRepl;
+function createStableRepl(env, opts, cb) {
+  process.stdout.write(`Welcome to Node.js ${process.version}.\n` +
+      'Type ".help" for more information.\n');
 
-function createRepl(env, opts, cb) {
   if (typeof opts === 'function') {
     cb = opts;
     opts = null;
@@ -31,13 +40,13 @@ function createRepl(env, opts, cb) {
 
   if (env.NODE_REPL_MODE) {
     opts.replMode = {
-      'strict': REPL.REPL_MODE_STRICT,
-      'sloppy': REPL.REPL_MODE_SLOPPY,
+      'strict': StableREPL.REPL_MODE_STRICT,
+      'sloppy': StableREPL.REPL_MODE_SLOPPY,
     }[env.NODE_REPL_MODE.toLowerCase().trim()];
   }
 
   if (opts.replMode === undefined) {
-    opts.replMode = REPL.REPL_MODE_SLOPPY;
+    opts.replMode = StableREPL.REPL_MODE_SLOPPY;
   }
 
   const historySize = Number(env.NODE_REPL_HISTORY_SIZE);
@@ -47,7 +56,13 @@ function createRepl(env, opts, cb) {
     opts.historySize = 1000;
   }
 
-  const repl = REPL.start(opts);
+  const repl = StableREPL.start(opts);
   const term = 'terminal' in opts ? opts.terminal : process.stdout.isTTY;
   repl.setupHistory(term ? env.NODE_REPL_HISTORY : '', cb);
 }
+
+async function createExperimentalRepl() {
+  const repl = new ExperimentalREPL();
+  await repl.start();
+  ExperimentalREPL.repl = repl; // For introspection
+}

lib/internal/repl/experimental/highlight.js

@@ -0,0 +1,47 @@
+'use strict';
+
+const emphasize = require('internal/repl/experimental/deps/emphasize');
+const util = require('util');
+
+function makeStyled(color) {
+  return (s) => `\x1b[${color[0]}m${s}\x1b[${color[1]}m`;
+}
+
+const sheet = {
+  'comment': makeStyled(util.inspect.colors.grey),
+  'quote': makeStyled(util.inspect.colors.grey),
+
+  'keyword': makeStyled(util.inspect.colors.green),
+  'addition': makeStyled(util.inspect.colors.green),
+
+  'number': makeStyled(util.inspect.colors.yellow),
+  'string': makeStyled(util.inspect.colors.green),
+  'meta meta-string': makeStyled(util.inspect.colors.cyan),
+  'literal': makeStyled(util.inspect.colors.cyan),
+  'doctag': makeStyled(util.inspect.colors.cyan),
+  'regexp': makeStyled(util.inspect.colors.cyan),
+
+  'attribute': undefined,
+  'attr': undefined,
+  'variable': makeStyled(util.inspect.colors.yellow),
+  'template-variable': makeStyled(util.inspect.colors.yellow),
+  'class title': makeStyled(util.inspect.colors.yellow),
+  'type': makeStyled(util.inspect.colors.yellow),
+
+  'symbol': makeStyled(util.inspect.colors.magenta),
+  'bullet': makeStyled(util.inspect.colors.magenta),
+  'subst': makeStyled(util.inspect.colors.magenta),
+  'meta': makeStyled(util.inspect.colors.magenta),
+  'meta keyword': makeStyled(util.inspect.colors.magenta),
+  'link': makeStyled(util.inspect.colors.magenta),
+
+  'built_in': makeStyled(util.inspect.colors.cyan),
+  'deletion': makeStyled(util.inspect.colors.red),
+
+  'emphasis': makeStyled(util.inspect.colors.italic),
+  'strong': makeStyled(util.inspect.colors.bold),
+  'formula': makeStyled(util.inspect.colors.inverse),
+};
+
+module.exports = (s) =>
+  emphasize.highlight('js', s, sheet).value;

lib/internal/repl/experimental/history.js

@@ -0,0 +1,51 @@
+'use strict';
+
+const { exports: fs } = require('internal/fs/promises');
+const permission = require('internal/process/permission');
+const path = require('path');
+const os = require('os');
+
+const {
+  StringPrototypeSplit,
+} = primordials;
+
+module.exports = async () => {
+  let handle;
+
+  try {
+    const historyPath = path.join(os.homedir(), '.node_repl_history');
+    if (permission.isEnabled() && permission.has('fs.write', historyPath) === false) {
+      process.stdout.write('\nAccess to FileSystemWrite is restricted.\n' +
+        'REPL session history will not be persisted.\n');
+      return {
+        __proto__: null,
+        history: [],
+        writeHistory: () => false,
+      };
+    }
+
+    handle = await fs.open(historyPath, 'a+', 0o0600);
+    const data = await handle.readFile({ encoding: 'utf8' });
+    const history = StringPrototypeSplit(data, os.EOL, 1000);
+    const writeHistory = async (d) => {
+      if (!handle) {
+        return false;
+      }
+      try {
+        await handle.truncate(0);
+        await handle.writeFile(d.join(os.EOL));
+        return true;
+      } catch {
+        handle.close().catch(() => undefined);
+        handle = null;
+        return false;
+      }
+    };
+    return { __proto__: null, history, writeHistory };
+  } catch {
+    if (handle) {
+      handle.close().catch(() => undefined);
+    }
+    return { __proto__: null, history: [], writeHistory: () => false };
+  }
+};