Re: Xpdf with or without Qt

[Leo Prikler]

> Should I create a custom channel with xpdf@4.02? Or even xpdf@5 to
> have
> a higher version number, but with the old 4.02 package code and
> source?
> Or a manifest including some time-machine thing, or a personal
> package
> transformation that compiles xpdf --with-source=...?
It's up to you, but some options are worse than others.
The easiest thing would be to inherit xpdf in your manifest and build
it from the old source.  That should work pretty well and also update
xpdf if any of its dependencies change.  You could also copy the entire
4.02 recipe to your history channel.  Either way, make sure to refer to
it as xpdf@4.02 when installing from command-line or directly by
variable xpdf-4.02 when using it in a manifest.  Do not create "higher"
versions for your own needs (unless they actually make sense, e.g.
you're packaging the yet unavailable version 4.04-alpha-we-got-back-
motif), that would conflict with Guix if a version 5 shipped, that had
Qt as an optional input with a Motif fallback.
Another would be to use inferiors from a manifest.  Inferiors basically
work like time-machine, but expressed in terms of Scheme code.
A third option would be to generate an environment, that has xpdf@4.02
through time-machine and add that environment as a gcroot.  Then you can invoke 
xpdf commands from that path and even source its etc/profile (inside your 
.bash_profile for instance) at startup.

Which one you grok the most is up to you, but it's definitely fun to
experiment 🙂

Regards,
Leo