Add an option to run fpm in a subdirectory

[certik]

Currently fpm must be run from the root directory where fpm.toml is. We should extend the usage to also work in any subdirectory of the project. Just like git works. That way you can go into into a subdirectory, use vim to edit a file and do fpm build or fpm test to run tests right away. Currently you have to have two terminals open, one where you run fpm build and another way where you can go into subdirectories to edit files.

Related issues: #411, #410.

[awvwgk]

As a vim user I have to strongly disagree on the above issue, so far it never occurred to me to leave the project root directory to edit a file.

Joke aside, a -C like option would be a welcome addition. I would prefer we find a way to implement it without explicitly carrying around the current working directory in the fpm source and pass it along to shell processes spawned by execute_command_line, maybe there is a simple solution to change the working directory for the process using stdlib_os.

[LKedward]

Duplicate of #172. See there for some brief discussion of using chdir for this.

[certik]

Closing in favor of #172.

[certik]

As a vim user I have to strongly disagree on the above issue, so far it never occurred to me to leave the project root directory to edit a file.

Can you be more specific what you strongly disagree with? What I described is a very common workflow situation, as for example described in #172.

[awvwgk]

Just a curiosity I noticed, many people use cd src; vim fpm.f90 rather than just using vim src/fpm.f90. The latter will retain the working directory as the project toplevel and allow to easily run commands with :!fpm run from inside vim, together with the netrw built-in file navigator (:E) I usually tend to open a single vim session while working on a project without ever changing directories. It's quite liberating to know you can always run any command straight from vim in the project root.

[certik]

I see. Yes, I used to use :!... a lot. I even have this in my .vimrc:

map <F10> :!/usr/bin/env python %<CR>

To run the currently opened file. But being in the current directory and :!fpm run should now work also due to #483. I also frequently escape vim and do git diff . to see the changes just in this directory, ls, etc.