Under OS X, the default key layout binds the following:
CMD - Super
ALT - Meta
The "super" key map is in turn populated with commands to simulate typical OS X key bindings like CMD-X, CMD-C, and CMD-V for cut, copy, and paste, respectively.
The problem with this layout is that there is no "compose" key, so it's impossible to write normal characters like "[", "]", "|", "\" etc. Normally, they are typed using the ALT key.
I propose that we change it to:
CMD - Meta
ALT - Compose
This keyboard layout, incidentally, is the one used by the Carbon "mac" port of Emacs (which is about to be integrated into the Emacs repository).
Unless anybody objects, I'll do this change in the next couple of days.
-- Anders Lindgren