Add partial support for getcmdtype() function

[jphalip]

The getcmdtype() could be called from inside a prompt (search, expression, command), or from a remapping. Apparently IdeaVim currently doesn't support nested prompts (e.g. by typing :<C-r>= to show an expression prompt inside a command prompt), so it wouldn't be functional in that case.

It should work in a remapping though, e.g.: :cnoremap <F2> <C-r>=getcmdtype()<CR>. Could you advise on how I could unit test this?

For context, this is the remap that I'm using this for:

cnoremap <expr> <Esc> getcmdtype() =~ '[/?]' ? '<CR><Esc>' : '<Esc>'

This is so that if you press <Escape> during a search before you press enter, it keeps the cursor at the first search result instead of jumping back to where the cursor was before the search started. This enforces a behavior that you find in most text search tools, including IntelliJ's built-in search.

[jphalip]

By the way, do you know what the "input command" (labelled @) corresponds to? For reference, here's the manual entry:

getcmdtype()

		Return the current command-line type. Possible return values
		are:
		    :	normal Ex command
		    >	debug mode command [debug-mode](https://neovim.io/doc/user/repeat.html#debug-mode)
		    /	forward search command
		    ?	backward search command
		    @	[input()](https://neovim.io/doc/user/builtin.html#input()) command
		    -  	[:insert](https://neovim.io/doc/user/insert.html#%3Ainsert) or [:append](https://neovim.io/doc/user/insert.html#%3Aappend) command
		    =	[i_CTRL-R_=](https://neovim.io/doc/user/insert.html#i_CTRL-R_%3D)  
		Only works when editing the command line, thus requires use of
		[c_CTRL-\_e](https://neovim.io/doc/user/cmdline.html#c_CTRL-%5C_e) or [c_CTRL-R_=](https://neovim.io/doc/user/cmdline.html#c_CTRL-R_%3D) or an expression mapping.
		Returns an empty string otherwise.
		Also see [getcmdpos()](https://neovim.io/doc/user/builtin.html#getcmdpos()), [setcmdpos()](https://neovim.io/doc/user/builtin.html#setcmdpos()) and [getcmdline()](https://neovim.io/doc/user/builtin.html#getcmdline()).

[citizenmatt]

The input command is the prompt shown when someone calls the input() function. So you could do something like this in Vim:

cmap <expr> z getcmdtype()

Now every time you type z in any kind of prompt, it will add the appropriate symbol to the prompt text. For a command, you'll get a : symbol and search will give / or ?. If you then type:

:call input("Prompt> ")

You'll get an input prompt for some kind of text (e.g. Vim script to capture something) and typing z will add @ to the prompt.

As for testing, a simple map like that would do it. Something like:

enterCommand("cmap <expr> z getcmdtype()")
typeText(":z")
assertEquals(":", injector.commandLine.visibleText)

or

enterCommand("cmap <expr> z getcmdtype()")
typeText("/fooz")
assertEquals("foo/", injector.commandLine.visibleText)

etc. Testing the expression register would be very similar, but with a different map:

enterCommand("cnoremap <F2> <C-r>=getcmdtype()<CR>")
typeText("?foo<F2>")
assertEquals("foo?", injector.commandLine.visibleText)

[jphalip]

@citizenmatt Thanks a lot for the details. I just added some tests for :/?=. However, I'm not sure input, insert, and append command would be supported since I think they'd require nested prompts, which doesn't work in IdeaVim. Also, I'm not sure about the debug mode (>) -- Is that reproducible and testable with IdeaVim?

[citizenmatt]

Looks good to me, thanks. I wouldn't worry about debug-mode, it's not supported by IdeaVim.

[AlexPl292]

Sweet, thank you!