Add support for receiving a presentation over stdin

Author: kgryte

lib/node_modules/@stdlib/repl/presentation/bin/cli

@@ -25,6 +25,7 @@
 var resolve = require( 'path' ).resolve;
 var readFileSync = require( '@stdlib/fs/read-file' ).sync;
 var CLI = require( '@stdlib/tools/cli' );
+var stdin = require( '@stdlib/process/read-stdin' );
 var REPL = require( '@stdlib/repl' );
 var lowercase = require( '@stdlib/string/lowercase' );
 var Presentation = require( './../lib' ); // eslint-disable-line stdlib/no-redeclare
@@ -36,6 +37,7 @@ var Presentation = require( './../lib' ); // eslint-disable-line stdlib/no-redec
 * Main execution sequence.
 *
 * @private
+* @returns {void}
 */
 function main() {
 	var flags;
@@ -84,6 +86,8 @@ function main() {
 	if ( flags.timeout ) {
 		opts1.timeout = parseInt( flags.timeout, 10 );
 	}
+	// Create a new REPL instance:
+	repl = new REPL( opts1 );
 
 	// Handle presentation options...
 	opts2 = {};
@@ -121,11 +125,12 @@ function main() {
 	if ( flags.autoclear === false ) {
 		opts2.autoClear = flags.autoclear;
 	}
+	// Check if we are receiving data from `stdin`...
+	if ( !process.stdin.isTTY ) {
+		return stdin( onRead );
+	}
 	opts2.load = args[ 0 ];
 
-	// Create a new REPL instance:
-	repl = new REPL( opts1 );
-
 	// Create a new REPL presentation:
 	pres = new Presentation( repl, opts2 );
 
@@ -146,6 +151,33 @@ function main() {
 	function onChange() {
 		pres.show();
 	}
+
+	/**
+	* Callback invoked upon reading from `stdin`.
+	*
+	* @private
+	* @param {(Error|null)} error - error object
+	* @param {Buffer} text - text
+	* @returns {void}
+	*/
+	function onRead( error, text ) {
+		var pres;
+		if ( error ) {
+			process.exitCode = 1;
+			return console.error( 'Error: %s', error.message ); // eslint-disable-line no-console
+		}
+		// Create a new REPL presentation:
+		pres = new Presentation( text.toString(), repl, opts2 );
+
+		// Render the first slide:
+		pres.show();
+
+		// Check whether to begin watching the source presentation file...
+		if ( flags.watch ) {
+			pres.on( 'change', onChange );
+			pres.watch();
+		}
+	}
 }
 
 main();