Bind Ctrl+Left to emacs-backward-word (and Right to forward)

Binds some additional sequences to emacs-backward-word and
emacs-forward-word. The problem is that terminfo doesn't know about
Ctrl+ArrowKeys, so one has to resort to using raw sequences as used
in the wild. The sequences were copied from Debian's /etc/inputrc
(readline configuration), so they should be fairly portable.
It works in xterm and rxvt terminals and doesn't work on
TERM=linux (virtual console) as Ctrl+Arrows send the same sequence
as Arrows alone.

http://zshwiki.org/home/zle/bindkeys
http://sources.debian.net/src/readline6/6.2+dfsg-0.1/debian/inputrc?hl=44#L44

modules/editor/init.zsh

@@ -29,6 +29,8 @@ zmodload zsh/terminfo
 typeset -gA key_info
 key_info=(
   'Control'   '\C-'
+  'ControlLeft'  '\e[1;5D \e[5D \e\e[D'  # sequences from Debian's inputrc
+  'ControlRight' '\e[1;5C \e[5C \e\e[C'
   'Escape'    '\e'
   'Meta'      '\M-'
   'Backspace' "^?"
@@ -57,6 +59,12 @@ key_info=(
   'BackTab'   "$terminfo[kcbt]"
 )
 
+# additionally from Debian's inputrc
+if [[ "$TERM" = *rxvt* ]]; then
+  key_info[ControlLeft]+=' \eOd'
+  key_info[ControlRight]+=' \eOc'
+fi
+
 # Set empty $key_info values to an invalid UTF-8 sequence to induce silent
 # bindkey failure.
 for key in "${(k)key_info[@]}"; do
@@ -206,10 +214,12 @@ bindkey -d
 # Emacs Key Bindings
 #
 
-for key ("$key_info[Escape]"{B,b}) bindkey -M emacs "$key" emacs-backward-word
-for key ("$key_info[Escape]"{F,f}) bindkey -M emacs "$key" emacs-forward-word
-bindkey -M emacs "$key_info[Escape]$key_info[Left]" emacs-backward-word
-bindkey -M emacs "$key_info[Escape]$key_info[Right]" emacs-forward-word
+for key ("${(s: :)key_info[ControlLeft]}" \
+         "$key_info[Escape]"{B,b} "$key_info[Escape]$key_info[Left]")
+  bindkey -M emacs "$key" emacs-backward-word
+for key ("${(s: :)key_info[ControlRight]}" \
+         "$key_info[Escape]"{F,f} "$key_info[Escape]$key_info[Right]")
+  bindkey -M emacs "$key" emacs-forward-word
 
 # Kill to the beginning of the line.
 for key in "$key_info[Escape]"{K,k}