Creating mappings for command-line mode

Question

I have made a few mappings for my personal configuration file, and I think I am getting a hang of it, however, I am wondering if there are any particular tricks to create mappings for command-line mode.

I know that there are keys like Ctrl+h for deleting the character before the cursor or Ctrl+Left for moving one WORD left, and I know how to remap these, but I am unsure what my options are when I want to make new ones. If I wanted a key (say Ctrl+_) which deletes the content of a parenthesis in insert mode, I would do this with:

imap <C-_> <C-O>dib

However, this relies on using normal mode, and I am unsure how, if possible, I could achieve something like that for command-line mode.

Answer 1

Vim provides a few mechanisms for inspecting the contents of the command-line (See Further Reading, below), but not many for directly manipulating it.

One way you could create the mapping you describe above would be to go via the command-line window:

:cnoremap <expr> <c-_> &cedit.'dib'.'<c-c>'

This creates an expression mapping that opens the command-line window, performs a normal mode dib and then returns to the regular command-line. The downside to this method is that it leaves the command-line window open after the mapping completes (although it no longer has focus). The window closes when you enter or cancel the command. See Mass's comment, below for a clever fix.

Your only other real option for complex cmaps is to use Ctrl-\e which allows you to replace the entire command-line with the result of an expression.

Further Reading

• :help cmdwin
• :help 'cedit'
• :help c_CTRL-\_e
• :help c_CTRL-R_=
• :help getcmdline()
• :help getcmdtype()
• :help getcmdpos()
• :help setcmdpos()