Invoke command-line mode in input waiting state

Question

For example, I'd like to map <leader>l to enter command-line mode with a command (AsyncRun followed by a space) partially typed in, so that I can continue to type to complete the command.

So typing <leader>l will enter command-line mode with the following command waiting for further input:

:AsyncRun

And then typing echo hello will complete the full command and pressing Enter will execute it:

:AsyncRun echo hello

Is there any way to create a mapping like this?

Answer 1

You can use the following normal mode mapping:

nnoremap <leader>l :AsyncRun<Space>

N.B. Instead of <Space>, you could just type a literal space character, but it's easier to see what the above is doing at a glance. If you wanted to start your rhs with a space, then using the <Space> notation is required. See :help map_space_in_rhs.

Answer 2

You can request input form the user using input(.

        :if input("Coffee or beer? ") == "beer"
        :  echo "Cheers!"
        :endif

This supports arbitrary completion (see :help input().

Alternatively, inputlist( will allow the user to select from a list of items, either by mouse or typing a number.

See also inputdialog( for a GUI alternative.