vim keyboard mapping problems on mac OSX - macos

Question

1.Env
vim7.3+zsh+iTerm2 on mavericks
2. Mapping Problem
Here are my problem list:
My vim could not get some shortcuts: <C-q>,<C-s>,<A-Left|Right|..>,<D-char>.
I could not map some special keys such as <A-char> , <A-S-char> , <C-A-char>in mac.
<C-q> and <C-s>
In iTerm2, <C-q> will delete whole line, (and <C-s> will launch Fwd-i-search).
It doesn't behave like start/stop character , so that I thought this problem is nothing to do with stty start and stty stop.
But after I add this into ~/.zshrc, I surprised to see that the map for <C-q> and <C-s> works well in Vim. At the same time it doesn't change the behavior of <C-q> and <C-s> in iTerm2(I don't know why).
stty start undef
stty stop undef
<A-char> problem in mac
In mac, mappings for <A-char> won't directly work in mac.
:inoremap <A-u> type some string A-u
:inoremap <A-p> type some string A-p
:inoremap
i õ * type some string A-u
i ð * type some string A-p
As far as I know about <A-char> in mac, hit <A-u> will print nothing but with a sound alert. hit <A-p> will print π. I found that map for π works well.
:inoremap π type some string A-p
Is it possible to map <A-u> in vim?
Another complex question, is it possible for <A-S-char>, <C-A-char>
:map <A-S-p> not work
:map ∏ works well(A-S-p will print `∏`)
:map <C-A-p> not work
:map <C-π> still not work
:map <C-S-p> do work
Another complex question related above, is it possible mapping <C-A-char>?
<A-Left|Right|UP|Down
In iTerm2 , hitting <A-Left|... will result in(iTerm2 doesn't bind any shortcut for them.):
<A-Up> print 'A' with a sound alert.
<A-Down> print 'B' with a sound alert.
<A-Left> print 'D' with a sound alert.
<A-Down> print 'C' with a sound alert.
In vim, <A-Left|... is same as <Left><Right><Up><Down> in insert mode , normal mode, visual mdoe and Ex Mode, etc.
<D-char>
Some keys about <D-char> are iTerms's own hotkeys, such as :
1. <D-q> will quit iTerm2
1. <D-w> will close current tab in iTerm2
On the other hand, the other keys such as <D-s> are not hotkey, and do not print any char in vim and terminal. Is it possible to map them in vim?

Answer 1

Map <C-1>
Vim doesn't provide keycode <C-1>, but you can use other unused vim keycodes instead
Potentially unused Vim keycodes that can be used include:
<F13> to <F37>
<S-F13> to <S-F37>
<xF1> to <xF4>
<S-xF1> to <S-xF4>
Type :set termcap to see which vim keycodes are unused.
If you want to use hotkey Ctrl+1, map it to Esc Sequence (such as ^[C-1) in terminal preference first, then bind this terminal keycode with an unused vim keycode such as <F13>, <xF1>, <t_bc>, etc.
"bind vim keycode `<F13>` to terminal keycode `^[C-1`
:set <F13>=^[C-1
:imap <F13> Input some characters
For more details, refer to fastcodes in vim
Map <A-char>
By default, <A-char> will print special character in mac. In generally, you can map this special character. Or you can remap <Alt> as Meta in your terminal.
Map <C-A-char> and <D-char>
Same with <C-1>, if you use termainal vim you could use fastcodes instead of.
Bind <C-A-char> with terminal any keycodes, for example : ^[C-A-a
Set vim fastkeycodes and do mapping:
Mapping:
:set <C-A-a>=^[C-A-a
:map <C-A-a> Input some characters