:optional and :recommended installs

[joeyhoer]

Some applications provide optional binary installs (e.g. Kaleidoscope's ksdiff, Github Desktop's github), while others install multiple GUI apps (e.g. NanoStudio).

Cask provides --no-binaries which will skip symlinking all executable binaries into /usr/local/bin. But offers no other methods to specify if any of these additional apps/binaries/tools should be installed.

Homebrew uses :optional and :required to denote special build actions, available via --with- and --without-. It would be great if Cask could reproduce this functionality, giving a little more control over what is installed.

Possibly related to #2992.

[vitorgalvao]

#2992 already covers most of this. As for using only some of a type of artifact, definitely not, at least for now. First we’ll need to fix how we install stuff, and only then we can think of something like this. It is a very niche request, though, and I’ve never seen any interest whatsoever from the core team or any user, so even in the future it’s unlikely it’ll be done without a PR.