How can I create mappings to execute specific Vim commands, depending on if a makefile exists?

Question

In general, I have makefiles setup anytime I'm working on C projects. To save and compile these projects, I've bound the ' key to do this:

map ' :wa<CR>:!make<CR>

However, I sometimes open up test files that don't have a makefile, and want to compile those quickly as well:

map ' :wa<CR>:!gcc % -o %< && ./&<<CR>

My question is, how do I create a function to detect if a makefile exists, and then execute the appropriate command? The pseudocode would be the following:

If (makefile exists)
    run make
else
    run gcc on the single file

The only knowledge I have on the vimscript for it would be that I have to bind the ' key to a function. Thanks for any help!

Answer 1

Wrap it into a function that should be called from your mapping, for instance:

func! MakeOrGcc()
    :write
    " check in the current working directory
    if filereadable('Makefile')
        :!make
    else
        :!gcc % -o %< && ./&<
    endif
endfunc

nnoremap ' :call MakeOrGcc()<CR>

Answer 2

Since you're already executing a shell command, you could just use a shell if to test that condition:

map ' :wa<CR>:!if [ -f Makefile ]; then make; else gcc % -o %< && ./&<; fi<CR>

Answer 3

Actually, one doesn't need makefiles in order to use make. So it is as simple as

:make all

when you have a "standard" makefile; or

:make foobar

when you've got only foobar.c