How can variant B imply variant A?

[Mojca Miklavec]

On Tue, Aug 21, 2012 at 9:46 PM, Jeremy Lavergne wrote:
>
>> "variant ... requires ..."?
>> - Is it possible to use "if port X is installed" inside Y's Portfile?
>
> This is just a bad idea: your package will install differently based on what's available, and not even consistently (e.g. archives). Use subports with the appropriate dependencies.

Something just came to my mind. Doesn't the following code do *exactly* that?
    depends_lib-append      path:lib/pkgconfig/pango.pc:pango

That is: if pango-devel is already installed, it would use
pango-devel, else it would use or install pango.

Mojca