Is it possible to offer an option for gtk-mac-integration?

[easior]

The formula gtk-mac-integration is useful in several aspects: to build an integrated menu with Mac OS X, or to install RAD tool Glade, etc. However, The installation of gtk-mac-integration would depend both on gtk+2 and gtk+3, it is inconvenient. Could the dependence on both GTK branchs be reduced to only one? I hope, it could be offered two option, e.g. gtk+2, gtk+3, which give the user a choice to install a proper GTK dependence.

[SMillerDev]

In a tap this can be done very easily doing depends_on "y" => :optional.
In homebrew core it won't be possible.

[easior]

Thank you for your comment @gromgit.
Actually, I have made my own gtk-mac-integration formula in my tap. There is still one thing I can't figure out:
how to let the options work as arbitrary one over two choices or both two?
In my situation, gtk+ is optional now, but gtk+3 couldn't be, because my modification is as follows
depends_on "gtk+" => :optional

[gromgit]

how to let the options work as arbitrary one over two choices or both two?

Please read https://docs.brew.sh/Formula-Cookbook#specifying-other-formulae-as-dependencies carefully. In particular:

• :optional generates an implicit with-foo option for the formula. This means that, given depends_on "foo" => :optional, the user must pass --with-foo in order to use the dependency.

If you don't tag gtk+3 as :optional too, it becomes a mandatory dependency.

[carlocab]

You could tag gtk+3 as :recommended.

[gromgit]

That's another option, though given the original request, building with only GTK+2 then becomes:

brew install --without-gtk+3 --with-gtk+ gtk-mac-integration

[gromgit]

@easior Forgot to mention: If you're using :optional, you need to read https://docs.brew.sh/Formula-Cookbook#adding-optional-steps as well. Depending on the formula, you may need to add conditional logic to configure the build accordingly.