Ideally, I'd like <A-left> to execute :tabmove -1 and <A-right> to execute :tabmove +1. However, when I put
nnoremap <A-left> :tabmove -1<cr>
nnoremap <A-right> :tabmove +1<cr>
in my .vimrc and try or , vim beeps and moves my cursor one character over in the direction I pressed. However, typing :tabmove -1<cr> directly into command mode gives the desired effect. How can I fix this? Thanks in advance.
Due to the way that the keyboard input is handled internally, this unfortunately isn't possible today in most terminals, but should work in GVIM. Some key combinations, like Ctrl + non-alphabetic cannot be mapped, and Ctrl + letter vs. Ctrl + Shift + letter cannot be distinguished. This is a known pain point, and the subject of various discussions on vim_dev and the #vim IRC channel.
As a workaround, use different keys, e.g. <Leader><Left> / <Leader><Right>.