Hi! Ricardo Wurmus <rek...@elephly.net> skribis:
> Myles English <mylesengl...@gmail.com> writes: > >> Hello Fede, Eric, >> >> on [2017-02-07] at 15:15 Federico Beffa writes: [...] >>> it seems that the only Python specific part of >>> 'package-with-explicit-python' is the keyword '#:python'. What do you >>> think of generalizing it by making it a function keyword argument and >>> move the procedure to its own module (maybe (guix build-system >>> utils)?). >> >> ...I came the same conclusion as Fede: it could be generalised. It is >> probably close to working for me (with respect to ghc) so I will keep >> going for now. I am not competent enough to generalise it but if >> someone else does I can help test it. > > I’m doing the same for some Perl packages. I defined a procedure > “package-for-perl-5.14” which takes a package and rewrites it. > > It looks like this: > > (define (package-for-perl-5.14 pkg) > (let* ((rewriter (package-input-rewriting `((,perl . ,perl-5.14)) > perl-5.14-package-name)) > (new (rewriter pkg))) > (package > (inherit new) > (arguments `(#:perl ,perl-5.14 > ,@(package-arguments new)))))) > > The problem here is that it doesn’t rewrite the “#:perl” argument > recursively, so the dependencies of a Perl package will still refer to > the latest version of Perl as that’s what’s used in the build system. > > We would need a solution that would take care of this problem for all > build systems. I agree that this is asking for generalization. Another instance of DAG rewriting is the ‘package-with-’ helpers in (guix build-system gnu). We should have a general form of transformation procedure that handles DAG traversal and memoization like all these procedures do. Ludo’.
