Is it possible for a command or function to end in command line mode?

Question

It's possible to configure a mapping such that command line mode is active after the key press.

For example, with a mapping :map H :help , pressing H results in command line mode being entered with :help as the current text.

The documentation for :normal says:

A ":" command must be completed as well. And you can't use "Q" or "gQ" to start Ex mode.

Therefore, it's not possible to execute :normal : and end up in command line mode.

Are there commands such that command line mode is active upon completion?

Can a Vimscript function be used where command line mode is active with some specified text, after running the function directly (i.e., via a :call entered in isolation, as opposed to being wrapped in a mapping that can result in command line mode)?

Answer 1

You can use the feedkeys() function for this purpose.

For example:

function! Edit()
    call feedkeys(':edit ', 'n')
endfunction

Then :call Edit() will enter the Ex command-line, enter :edit into it and leave the cursor there for the user to complete and eventually execute the Ex command.

As :help feedkeys() explains:

By default the string is added to the end of the typeahead buffer, [...] The function does not wait for processing of keys contained in {string}.

I also recommend that you take a close look at :help feedkeys() for the possible values of {mode}, I used 'n' for no-remap in my example, but there are more mode flags that you might find interesting for your specific situation.

Answer 2

The easiest solution: you'll need a mapping and have the mapping returns the value of a function that returns a sequence that will have us end in command mode.

Answer 3

I'm agree with Luc. feedkeys() should be avoided whenever possible.

Carefully using :map-<expr> (or even :h abbreviations, as you seem to "misuse" a command to compose another command, see :h :cnoreabbrev) works in 90+ percent of cases. But if you really want the user to input a line or two, you can always fake it with :h input() and :h execute().