Extend and improve acre

[aardschok]

Part of issue FUS-32

• Added launcher module
• Added which and execute function to core
• Retrieve PATH and PATHEXT from env in which, fallback to os.getenv if PATHEXT is not available

[BigRoy]

Still not too sure about having the execute and which in acre - because of the added complexity. Maybe we should pull this to a branch instead of the master, to visualize it isn't the live master? Or, since it hasn't been adopted by others yet (as far as I can tell) maybe just merge this but then get the cleaned up API out in a day or two.

[aardschok]

I think we can rename which to locate as that is exactly what the function docs say. This way we make it clear it locates the executable in the current environment.

[aardschok]

Tested it for Maya and Fusion deadline submission, had to add avalon-setup/bin/pythonpath and avalon-setup/git/pyblish-base to the environment to ensure the Avalon initialization within Maya worked properly. This might be a subject for a discussion.

[aardschok]

I do not think that we should care about familiarity of others when using this. We could have chosen where for all that matters because we are on Windows. If anything, locate is both which and where.

Let's tackle it from a pure logical standpoint without taking in account the OS in which it is used.

• which: this points more to the name of an object
• where: there points to the location of the object.

Now based on pure grammar: we already KNOW the object, we pass it on to the function. Taking that logic in account both where and locate make more sense because we are looking for the given object.

I am entirely in favor to use locate because which is not a standard and sounds illogical.

[BigRoy]

No, where on Windows has a different behavior - it's not the same. :) The function that's here in our code is exactly the functionality of which on UNIX.

The name which comes from the fact that the same executable name can be on your path, e.g. python.exe in Python3 and Python2. You use which python to find which of the two is being used. It's not locating both for you.

Again, subtle difference. I'm fine with locate if you like it much more. I just wanted to address that if you use which you'll have the added benefit of those on UNIX knowing the command since it's exactly that. :)

[aardschok]

Any objection to merging this?

[BigRoy]

Other than above note this is fine for me - it's a prototype. Like mentioned in our discussions I think the API can still simplify by just having the locate, build and merge

By the way, don't you think locate and discover sounds so very similar? When I saw the import statements I suddenly thought: "what's the difference?"

[aardschok]

Made some changes to the API, I would like to have a review on the prepare

I think that there is still some room for improvements