Add binding to termios, implement readline for repl

bin/node-repl

@@ -2,10 +2,6 @@
 
 puts = require("sys").puts;
 
-puts("Welcome to the Node.js REPL.");
-puts("Enter ECMAScript at the prompt.");
-puts("Tip 1: Use 'rlwrap node-repl' for a better interface");
-puts("Tip 2: Type Control-D to exit.");
 puts("Type '.help' for options.");
 
 require('repl').start();

lib/readline.js

@@ -0,0 +1,251 @@
+// Insperation for this code comes from Salvatore Sanfilippo's linenoise.
+// http://github.com/antirez/linenoise
+// Reference:
+// * http://invisible-island.net/xterm/ctlseqs/ctlseqs.html
+// * http://www.3waylabs.com/nw/WWW/products/wizcon/vt220.html
+
+var kHistorySize = 30;
+var kBufSize = 10*1024;
+
+
+var Buffer = require('buffer').Buffer;
+var inherits = require('sys').inherits;
+var EventEmitter = require('events').EventEmitter;
+var stdio = process.binding('stdio');
+
+
+
+exports.createInterface = function (output, isTTY) {
+  return new Interface(output, isTTY);
+};
+
+function Interface (output, isTTY) {
+  this.output = output;
+
+  this.setPrompt("node> ");
+
+  // Current line
+  this.buf = new Buffer(kBufSize);
+  this.buf.used = 0;
+
+  if (!isTTY) {
+    this._tty = false;
+  } else {
+    // input refers to stdin
+
+    // Check process.env.TERM ?
+    stdio.setRawMode(true);
+    this._tty = true;
+    this.columns = stdio.getColumns();
+
+    // Cursor position on the line.
+    this.cursor = 0;
+
+    this.history = [];
+    this.historyIndex = -1;
+  }
+}
+
+inherits(Interface, EventEmitter);
+
+
+Interface.prototype.setPrompt = function (prompt, length) {
+  this._prompt = prompt;
+  this._promptLength = length ? length : Buffer.byteLength(prompt);
+};
+
+
+Interface.prototype.prompt  = function () {
+  if (this._tty) {
+    this.buf.used = 0;
+    this.cursor = 0;
+    this._refreshLine();
+  } else {
+    this.output.write(this._prompt);
+  }
+};
+
+
+Interface.prototype._addHistory = function () {
+  if (this.buf.used === 0) return "";
+
+  var b = new Buffer(this.buf.used);
+  this.buf.copy(b, 0, 0, this.buf.used);
+  this.buf.used = 0;
+
+  this.history.unshift(b);
+  this.historyIndex = -1;
+
+  this.cursor = 0;
+
+  // Only store so many
+  if (this.history.length > kHistorySize) this.history.pop();
+
+  return b.toString('utf8');
+};
+
+
+Interface.prototype._refreshLine  = function () {
+  if (this._closed) return;
+
+  stdio.setRawMode(true);
+
+  // Cursor to left edge.
+  this.output.write('\x1b[0G');
+
+  // Write the prompt and the current buffer content.
+  this.output.write(this._prompt);
+  if (this.buf.used > 0) {
+    this.output.write(this.buf.slice(0, this.buf.used));
+  }
+
+  // Erase to right.
+  this.output.write('\x1b[0K');
+
+  // Move cursor to original position.
+  this.output.write('\x1b[0G\x1b[' + (this._promptLength + this.cursor) + 'C');
+};
+
+
+Interface.prototype.close = function (d) {
+  if (this._tty) {
+    stdio.setRawMode(false);
+  }
+  this.emit('close');
+  this._closed = true;
+};
+
+
+Interface.prototype.write = function (d) {
+  if (this._closed) return;
+  return this._tty ? this._ttyWrite(d) : this._normalWrite(d);
+};
+
+
+Interface.prototype._normalWrite = function (b) {
+  for (var i = 0; i < b.length; i++) {
+    var code = b instanceof Buffer ? b[i] : b.charCodeAt(i);
+    if (code === '\n'.charCodeAt(0) || code === '\r'.charCodeAt(0)) {
+      var s = this.buf.toString('utf8', 0, this.buf.used);
+      this.emit('line', s);
+      this.buf.used = 0;
+    } else {
+      this.buf[this.buf.used++] = code;
+    }
+  }
+};
+
+
+Interface.prototype._ttyWrite = function (b) {
+  switch (b[0]) {
+    /* ctrl+c */
+    case 3:
+      //process.kill(process.pid, "SIGINT");
+      this.close();
+      break;
+
+    case 4:     /* ctrl+d */
+      this.close();
+      break;
+
+    case 13:    /* enter */
+      var line = this._addHistory();
+      this.output.write('\n\x1b[0G');
+      stdio.setRawMode(false);
+      this.emit('line', line);
+      break;
+
+    case 127:   /* backspace */
+    case 8:     /* ctrl+h */
+      if (this.cursor > 0 && this.buf.used > 0) {
+        for (var i = this.cursor; i < this.buf.used; i++) {
+          this.buf[i-1] = this.buf[i];
+        }
+        this.cursor--;
+        this.buf.used--;
+        this._refreshLine();
+      }
+      break;
+
+    case 21: /* Ctrl+u, delete the whole line. */
+      this.cursor = this.buf.used = 0;
+      this._refreshLine();
+      break;
+
+    case 11: /* Ctrl+k, delete from current to end of line. */
+      this.buf.used = this.cursor;
+      this._refreshLine();
+      break;
+
+    case 1: /* Ctrl+a, go to the start of the line */
+      this.cursor = 0;
+      this._refreshLine();
+      break;
+
+    case 5: /* ctrl+e, go to the end of the line */
+      this.cursor = this.buf.used;
+      this._refreshLine();
+      break;
+
+    case 27:    /* escape sequence */
+      if (b[1] === 91 && b[2] === 68) {
+        // left arrow
+        if (this.cursor > 0) {
+          this.cursor--;
+          this._refreshLine();
+        }
+      } else if (b[1] === 91 && b[2] === 67) {
+        // right arrow
+        if (this.cursor != this.buf.used) {
+          this.cursor++;
+          this._refreshLine();
+        }
+      } else if (b[1] === 91 && b[2] === 65) {
+        // up arrow
+        if (this.historyIndex + 1 < this.history.length) {
+          this.historyIndex++;
+          this.history[this.historyIndex].copy(this.buf, 0);
+          this.buf.used = this.history[this.historyIndex].length;
+          // set cursor to end of line.
+          this.cursor = this.buf.used;
+
+          this._refreshLine();
+        }
+
+      } else if (b[1] === 91 && b[2] === 66) {
+        // down arrow
+        if (this.historyIndex > 0) {
+          this.historyIndex--;
+          this.history[this.historyIndex].copy(this.buf, 0);
+          this.buf.used = this.history[this.historyIndex].length;
+          // set cursor to end of line.
+          this.cursor = this.buf.used;
+          this._refreshLine();
+
+        } else if (this.historyIndex === 0) {
+          this.historyIndex = -1;
+          this.cursor = 0;
+          this.buf.used = 0;
+          this._refreshLine();
+        }
+      }
+      break;
+
+    default:
+      if (this.buf.used < kBufSize) {
+        for (var i = this.buf.used + 1; this.cursor < i; i--) {
+          this.buf[i] = this.buf[i-1];
+        }
+        this.buf[this.cursor++] = b[0];
+        this.buf.used++;
+
+        if (this.buf.used == this.cursor) {
+          this.output.write(b);
+        } else {
+          this._refreshLine();
+        }
+      }
+      break;
+  }
+};
+