feat: add REPL pager

PR-URL: #2162
Closes: #2149
Co-authored-by: Athan Reines <[email protected]>
Reviewed-by: Athan Reines <[email protected]> 
Signed-off-by: Snehil Shah <[email protected]>

Author: Snehil-Shah

lib/node_modules/@stdlib/repl/README.md

@@ -81,6 +81,7 @@ The function supports specifying the following settings:
 
 -   **autoClosePairs**: boolean indicating whether to automatically insert matching brackets, parentheses, and quotes. Default: `true`.
 -   **autoDeletePairs**: boolean indicating whether to automatically delete adjacent matching brackets, parentheses, and quotes. Default: `true`.
+-   **autoPage**: boolean indicating whether to automatically page return values having a display size exceeding the visible screen. When streams are TTY, the default is `true`; otherwise, the default is `false`.
 -   **completionPreviews**: boolean indicating whether to display completion previews for auto-completion. When streams are TTY, the default is `true`; otherwise, the default is `false`.
 
 #### REPL.prototype.createContext()

lib/node_modules/@stdlib/repl/lib/auto_close_pairs.js

@@ -63,15 +63,19 @@ function isQuote( ch ) {
 * @private
 * @constructor
 * @param {Object} rli - readline instance
+* @param {boolean} autoClose - boolean indicating whether auto-closing should be initially enabled
+* @param {boolean} autoDelete - boolean indicating whether auto-deleting should be initially enabled
 * @returns {AutoCloser} auto-closer instance
 */
-function AutoCloser( rli ) {
+function AutoCloser( rli, autoClose, autoDelete ) {
 	if ( !(this instanceof AutoCloser) ) {
-		return new AutoCloser( rli );
+		return new AutoCloser( rli, autoClose, autoDelete );
 	}
 	debug( 'Creating an auto-closer...' );
 	this._rli = rli;
 	this._ignoreBackspace = false;
+	this._autoClose = autoClose;
+	this._autoDelete = autoDelete;
 	return this;
 }
 
@@ -239,6 +243,62 @@ setNonEnumerableReadOnly( AutoCloser.prototype, '_autodeleteOpenSymbol', functio
 	return true;
 });
 
+/**
+* Disables auto-closing pairs.
+*
+* @name disableAutoClose
+* @memberof AutoCloser.prototype
+* @type {Function}
+* @returns {AutoCloser} auto-close instance
+*/
+setNonEnumerableReadOnly( AutoCloser.prototype, 'disableAutoClose', function disableAutoClose() {
+	debug( 'Disabling auto-closing pairs...' );
+	this._autoClose = false;
+	return this;
+});
+
+/**
+* Enables auto-closing pairs.
+*
+* @name enableAutoClose
+* @memberof AutoCloser.prototype
+* @type {Function}
+* @returns {AutoCloser} auto-close instance
+*/
+setNonEnumerableReadOnly( AutoCloser.prototype, 'enableAutoClose', function enableAutoClose() {
+	debug( 'Enabling auto-closing pairs...' );
+	this._autoClose = true;
+	return this;
+});
+
+/**
+* Disables auto-deleting pairs.
+*
+* @name disableAutoDelete
+* @memberof AutoCloser.prototype
+* @type {Function}
+* @returns {AutoCloser} auto-close instance
+*/
+setNonEnumerableReadOnly( AutoCloser.prototype, 'disableAutoDelete', function disableAutoDelete() {
+	debug( 'Disabling auto-deleting pairs...' );
+	this._autoDelete = false;
+	return this;
+});
+
+/**
+* Enables auto-deleting pairs.
+*
+* @name enableAutoDelete
+* @memberof AutoCloser.prototype
+* @type {Function}
+* @returns {AutoCloser} auto-close instance
+*/
+setNonEnumerableReadOnly( AutoCloser.prototype, 'enableAutoDelete', function enableAutoDelete() {
+	debug( 'Enabling auto-deleting pairs...' );
+	this._autoDelete = true;
+	return this;
+});
+
 /**
 * Callback which should be invoked **before** a "keypress" event is processed by a readline interface.
 *
@@ -253,6 +313,9 @@ setNonEnumerableReadOnly( AutoCloser.prototype, 'beforeKeypress', function befor
 	var cursor;
 	var line;
 
+	if ( !this._autoDelete ) {
+		return false;
+	}
 	if ( !key || key.name !== 'backspace' ) {
 		return false;
 	}
@@ -294,6 +357,9 @@ setNonEnumerableReadOnly( AutoCloser.prototype, 'onKeypress', function onKeypres
 	var cursor;
 	var line;
 
+	if ( !this._autoClose ) {
+		return false;
+	}
 	cursor = this._rli.cursor;
 	line = this._rli.line;
 

lib/node_modules/@stdlib/repl/lib/commands.js

@@ -48,6 +48,7 @@ var isKeyword = require( './commands/is_keyword.js' );
 var onLicense = require( './commands/license_text.js' );
 var onLoad = require( './commands/load.js' );
 var onLoadWorkspace = require( './commands/load_workspace.js' );
+var onPager = require( './commands/pager.js' );
 var onPresentationStart = require( './commands/presentation_start.js' );
 var onPresentationStop = require( './commands/presentation_stop.js' );
 var onQuit = require( './commands/quit.js' );
@@ -116,6 +117,7 @@ function commands( repl ) {
 	cmds.push( [ 'license', onLicense( repl ), false ] );
 	cmds.push( [ 'load', onLoad( repl ), false ] );
 	cmds.push( [ 'loadWorkspace', onLoadWorkspace( repl ), false ] );
+	cmds.push( [ 'pager', onPager( repl ), false ] );
 	cmds.push( [ 'presentationStart', onPresentationStart( repl ), false ] );
 	cmds.push( [ 'presentationStop', onPresentationStop( repl ), false ] );
 	cmds.push( [ 'quit', onQuit( repl ), false ] );

lib/node_modules/@stdlib/repl/lib/commands/pager.js

@@ -0,0 +1,64 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2024 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+/* eslint-disable no-underscore-dangle */
+
+'use strict';
+
+// MAIN //
+
+/**
+* Returns a callback to be invoked upon calling the `pager` command.
+*
+* @private
+* @param {REPL} repl - REPL instance
+* @returns {Function} callback
+*/
+function command( repl ) {
+	return onCommand;
+
+	/**
+	* Enables paging for a provided string.
+	*
+	* @private
+	* @param {string} value - input string
+	*/
+	function onCommand( value ) {
+		var ostream = repl._ostream;
+
+		// Check whether auto-paging is already enabled...
+		if ( repl.settings( 'autoPage' ) ) {
+			// Nothing needed here, as we can defer to already enabled behavior:
+			ostream.write( value );
+			return;
+		}
+		// Temporarily enable paging:
+		ostream.enablePaging();
+
+		// Write the input value:
+		ostream.write( value );
+
+		// Disable paging:
+		ostream.disablePaging();
+	}
+}
+
+
+// EXPORTS //
+
+module.exports = command;

lib/node_modules/@stdlib/repl/lib/completer_preview.js

@@ -44,14 +44,18 @@ var debug = logger( 'repl:completer:preview' );
 * @param {Object} rli - readline instance
 * @param {Function} completer - function for generating possible completions
 * @param {WritableStream} ostream - writable stream
+* @param {boolean} enabled - boolean indicating whether the completer should be initially enabled
 * @returns {PreviewCompleter} completer instance
 */
-function PreviewCompleter( rli, completer, ostream ) {
+function PreviewCompleter( rli, completer, ostream, enabled ) {
 	if ( !(this instanceof PreviewCompleter) ) {
-		return new PreviewCompleter( rli, completer, ostream );
+		return new PreviewCompleter( rli, completer, ostream, enabled );
 	}
 	debug( 'Creating a preview completer...' );
 
+	// Initialize a flag indicating whether the preview completer is enabled:
+	this._enabled = enabled;
+
 	// Cache a reference to the provided readline interface:
 	this._rli = rli;
 
@@ -76,6 +80,7 @@ function PreviewCompleter( rli, completer, ostream ) {
 * @private
 * @name _completionCallback
 * @memberof PreviewCompleter.prototype
+* @type {Function}
 * @returns {Function} completion callback
 */
 setNonEnumerableReadOnly( PreviewCompleter.prototype, '_completionCallback', function completionCallback() {
@@ -143,12 +148,16 @@ setNonEnumerableReadOnly( PreviewCompleter.prototype, '_completionCallback', fun
 *
 * @name clear
 * @memberof PreviewCompleter.prototype
+* @type {Function}
 * @returns {void}
 */
 setNonEnumerableReadOnly( PreviewCompleter.prototype, 'clear', function clear() {
 	var preview;
 	var N;
 
+	if ( !this._enabled ) {
+		return;
+	}
 	preview = this._preview;
 
 	// If no preview currently displayed, nothing to clear...
@@ -173,16 +182,51 @@ setNonEnumerableReadOnly( PreviewCompleter.prototype, 'clear', function clear()
 	this._preview = '';
 });
 
+/**
+* Disables the preview completer.
+*
+* @name disable
+* @memberof PreviewCompleter.prototype
+* @type {Function}
+* @returns {PreviewCompleter} completer instance
+*/
+setNonEnumerableReadOnly( PreviewCompleter.prototype, 'disable', function disable() {
+	this.clear();
+
+	debug( 'Disabling the preview completer...' );
+	this._enabled = false;
+
+	return this;
+});
+
+/**
+* Enables the preview completer.
+*
+* @name enable
+* @memberof PreviewCompleter.prototype
+* @type {Function}
+* @returns {PreviewCompleter} completer instance
+*/
+setNonEnumerableReadOnly( PreviewCompleter.prototype, 'enable', function enable() {
+	debug( 'Enabling the preview completer...' );
+	this._enabled = true;
+	return this;
+});
+
 /**
 * Callback for handling a "keypress" event.
 *
 * @name onKeypress
 * @memberof PreviewCompleter.prototype
+* @type {Function}
 * @param {string} data - input data
 * @param {(Object|void)} key - key object
 * @returns {void}
 */
 setNonEnumerableReadOnly( PreviewCompleter.prototype, 'onKeypress', function onKeypress() {
+	if ( !this._enabled ) {
+		return;
+	}
 	// Check for existing content beyond the cursor which could "collide" with a preview completion...
 	if ( /[^a-zA-Z0-9_$]/.test( this._rli.line.substring( this._rli.cursor ) ) ) { // FIXME: this is not robust (see https://mathiasbynens.be/notes/javascript-identifiers)
 		return;
@@ -199,14 +243,22 @@ setNonEnumerableReadOnly( PreviewCompleter.prototype, 'onKeypress', function onK
 *
 * @name beforeKeypress
 * @memberof PreviewCompleter.prototype
+* @type {Function}
 * @param {string} data - input data
 * @param {(Object|void)} key - key object
 * @returns {void}
 */
 setNonEnumerableReadOnly( PreviewCompleter.prototype, 'beforeKeypress', function beforeKeypress( data, key ) {
+	if ( !this._enabled ) {
+		return;
+	}
 	if ( !key || this._preview === '' ) {
 		return;
 	}
+	// Avoid clashing with existing TAB completion behavior...
+	if ( key.name === 'tab' ) {
+		return this.clear();
+	}
 	// Handle the case where the user is not at the end of the line...
 	if ( this._rli.cursor !== this._rli.line.length ) {
 		// If a user is in the middle of a line and presses ENTER, clear the preview string, as the preview was not accepted prior to executing the expression...

lib/node_modules/@stdlib/repl/lib/defaults.js

@@ -86,6 +86,9 @@ function defaults() {
 			// Flag indicating whether to automatically delete adjacent matching brackets, parentheses, and quotes:
 			'autoDeletePairs': true,
 
+			// Flag indicating whether to enable automatically page return values requiring a display size exceeding the visible screen (note: default depends on whether TTY):
+			'autoPage': void 0,
+
 			// Flag indicating whether to enable the display of completion previews for auto-completion (note: default depends on whether TTY):
 			'completionPreviews': void 0
 		}

lib/node_modules/@stdlib/repl/lib/display_prompt.js

@@ -41,6 +41,10 @@ function displayPrompt( repl, preserveCursor ) {
 	var re;
 	var ws;
 
+	// Avoid displaying a prompt if the REPL is currently in paging mode...
+	if ( repl._ostream.isPaging ) {
+		return;
+	}
 	len = repl._cmd.length;
 	if ( len === 0 ) {
 		if ( repl._padding && repl._count >= 0 ) {