Is there a way to map the tab key to meta in emacs?

Question

I'm looking to rebind Meta to the tab key in my emacs environment. I've looked around but been unable to find anything other than binding it to command or option, which are slightly better but still not ideal.

Answer 1

You cannot do this in Emacs alone, you need to modify the keymap in your window system (*nux, Mac, MS Windows).

See the similar questions for the reasoning: Mapping Caps Lock to Control from within Emacs on Windows, elisp how to check if Shift key is pressed, and Can I send a keypress to Windows from Emacs?.

You can make the change in your window system - but it'd be helpful to know what that is...

Answer 2

If you use OS X, you can install KeyRemap4MacBook and use a private.xml like this:

<?xml version="1.0"?>
<root>
  <appdef>
    <appname>EMACS</appname>
    <equal>org.gnu.Emacs</equal>
  </appdef>
  <item>
    <name>tabtometa</name>
    <identifier>tabtometa</identifier>
    <only>EMACS</only>
    <autogen>__KeyOverlaidModifier__ KeyCode::TAB, KeyCode::OPTION_L, KeyCode::TAB</autogen>
  </item>
</root>

It changes tab to option when held but keeps it as tab when pressed.

If you want to use option to insert non-ASCII characters, change OPTION_L to CONTROL_R and use:

(setq ns-option-modifier 'nil)
(setq ns-right-control-modifier 'meta)