Duncan Coutts wrote:
Sadly not because portage is not clever enough to deal with the kind of dependencies you end up with by doing that. Portage does not know that some libs are installed for one ghc and some for another, so it'd try and satisfy a dependency for mtl using the mtl you'd installed for ghc-6.4.2 when in fact you were building something for 6.6.1.
You may have heard of other new portage features that sound like they'd help, they don't. We've thought about this a lot and it is not feasible in with the current portage.
We could slot multiple versions of a lib for the same ghc, but not slot ghc itself.
Why not library slots named ghc-6.4 ghc-6.6 ghc-6.8 (or finer), each depending on the repective compiler slot? The different slots of gtk+ also depend on different slots of glib. Wolfram