From 09af242c898888697933b00a38a7c84a9a55ac38 Mon Sep 17 00:00:00 2001
From: Matt Ranney <mjr@ranney.com>
Date: Mon, 7 Jun 2010 16:43:50 -0700
Subject: [PATCH] Support more readline navigation keys.

---
 lib/readline.js | 105 ++++++++++++++++++++++++++++++++----------------
 lib/repl.js     |   3 +-
 2 files changed, 72 insertions(+), 36 deletions(-)

diff --git a/lib/readline.js b/lib/readline.js
index 9a1c21e83f..586f42209e 100644
--- a/lib/readline.js
+++ b/lib/readline.js
@@ -135,7 +135,36 @@ Interface.prototype._normalWrite = function (b) {
   }
 };
 
+Interface.prototype._historyNext = function () {
+  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();
+  }
+};
+
+Interface.prototype._historyPrev = function () {
+  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();
+  }
+};
+
+// handle a write from the tty
 Interface.prototype._ttyWrite = function (b) {
   switch (b[0]) {
     /* ctrl+c */
@@ -144,8 +173,16 @@ Interface.prototype._ttyWrite = function (b) {
       this.close();
       break;
 
-    case 4:     /* ctrl+d */
-      this.close();
+    case 4: // control-d, delete right or EOF
+      if (this.cursor === 0 && this.buf.used === 0) {
+        this.close();
+      } else if (this.cursor < this.buf.used) {
+        for (var i = this.cursor; i < this.buf.used; i++) {
+          this.buf[i] = this.buf[i+1];
+        }
+        this.buf.used--;
+        this._refreshLine();
+      }
       break;
 
     case 13:    /* enter */
@@ -187,47 +224,47 @@ Interface.prototype._ttyWrite = function (b) {
       this._refreshLine();
       break;
 
+    case 2: // control-b, back one character
+      if (this.cursor > 0) {
+        this.cursor--;
+        this._refreshLine();
+      }
+      break;
+
+    case 6: // control-f, forward one character
+      if (this.cursor != this.buf.used) {
+        this.cursor++;
+        this._refreshLine();
+      }
+      break;
+
+    case 14: // control-n, next history item
+      this._historyNext();
+      break;
+
+    case 16: // control-p, previous history item
+      this._historyPrev();
+      break;
+
     case 27:    /* escape sequence */
-      if (b[1] === 91 && b[2] === 68) {
-        // left arrow
+      if (b[1] === 98 && this.cursor > 0) { // meta-b - backward word
+
+      } else if (b[1] === 102 && this.cursor < this.buf.used) { // meta-f - forward word
+
+      } else 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
+      } 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();
-        }
+      } else if (b[1] === 91 && b[2] === 65) { // up arrow
+        this._historyPrev();
+      } else if (b[1] === 91 && b[2] === 66) { // down arrow
+        this._historyNext();
       }
       break;
 
diff --git a/lib/repl.js b/lib/repl.js
index afb28ea1e2..8df05f65c5 100644
--- a/lib/repl.js
+++ b/lib/repl.js
@@ -68,8 +68,7 @@ function REPLServer(prompt, stream) {
       // This try is for determining if the command is complete, or should
       // continue onto the next line.
       try {
-        // Scope the readline with self.scope
-        // with(){} and eval() are considered bad.
+        // Use evalcx to supply the global scope
         var ret = evalcx(self.buffered_cmd, scope, "repl");
         if (ret !== undefined) {
           scope._ = ret;