On Sat, 8 Jul 2017 21:05:57 +0200 Ulrich Mueller <u...@gentoo.org> wrote:
> >>>>> On Sat, 8 Jul 2017, Ciaran McCreesh wrote: > > > On Sat, 8 Jul 2017 16:39:29 +0200 > > Alexis Ballier <aball...@gentoo.org> wrote: > >> Indeed, makes sense. Would it also make sense to have some more > >> logical meaning in a future EAPI ? I mean, in every context I've > >> ever seen, applying a rule to the empty set is the neutral of that > >> rule, so that it preserves associativity. > >> That'd mean: || ( ) is false, && ( ) is true, ^^ ( ) is false, > > I have no strong opinion about this. Is it worth the effort of > changing the spec? > > >> ?? ( ) is false. > > I think ?? ( ) aka at-most-one-of should be true if empty. Maybe; this one is annoying I think since it is not associative per definition: ?? ( true ?? ( false false ) ) -> ?? ( true true ) -> false ?? ( ?? ( true false ) false ) -> ?? ( true false) -> true > > The sensible thing to do is ban it, and additionally ban use? ( ) > > inside || and ^^ (if we've not done that already...). > > Right. We have to check if this will break any eclass generated > dependencies, though. That's probably the best course of action indeed. Alexis.
