How to map ALT-return in .vimrc?

Question

I'm trying to map a combination of left alt and return keys in my .vimrc, yet without success.

I've added all those mappings to my .vimrc file, with no effect:

map <M-esc> itest0<return><esc>
map <M-cr> itest1<return><esc>
map <M-return> itest2<return><esc>
map <M-enter> itest3<return><esc>
map <M-[> itest4<return><esc>
map ^[ itest5<return><esc>

Some info:

After pressing Ctrl+v and then Alt+return:

• in my terminal i get ^[
• in vim (and gvim) in insert mode i get ^[
• After calling sed -n l i get:

^[
\033$

I'm using terminator on Arch Linux. Behaviour described is identical no matter whether I use vim or gvim. What am I supposed to do?

Answer 1

Due to the way that the keyboard input is handled internally, this unfortunately isn't generally possible today, even in GVIM. Some key combinations, like Ctrl + non-alphabetic cannot be mapped, and Ctrl + letter vs. Ctrl + Shift + letter cannot be distinguished. (Unless your terminal sends a distinct termcap code for it, which most don't.) In insert or command-line mode, try typing the key combination. If nothing happens / is inserted, you cannot use that key combination. This also applies to <Tab> / <C-I>, <CR> / <C-M> / <Esc> / <C-[> etc. (Only exception is <BS> / <C-H>.) Same applies to Alt and non-alphabetic keys. This is a known pain point, and the subject of various discussions on vim_dev and the #vim IRC channel.

Some people (foremost Paul LeoNerd Evans) want to fix that (even for console Vim in terminals that support this), and have floated various proposals, cp. http://groups.google.com/group/vim_dev/browse_thread/thread/626e83fa4588b32a/bfbcb22f37a8a1f8

But as of today, no patches or volunteers have yet come forward, though many have expressed a desire to have this in a future Vim release.