Re: Parameterized packages

[zimoun]

Hi Pierre,

I do not not if it related.

Currently, the option "--with-input" does not re-write the implicit
inputs. Probably for good reasons. :-)

For example, say I would like to have the version 3.4.3 of R (2017
old). This version is really old and had disappeared. Other said, it
is older than the introduction of "inferior"s and so "guix
time-machine" does not help (but that another story).
At this point, it is not matter the GCC version that it is used to
compile this R version.

Well, it is not too complicated:

  git show cbe1314a7e:gnu/packages/statistics.scm > /tmp/stuff/old-stats.scm
  # edit old-stats.scm to tweak the modules
  guix build -L /tmp r-minimal@3.4.3

Now, I would like to build the package r-rcpp at the version 1.0.3
which is introduced recently using the old R version 3.4.3. Well, the
naive idea is:

   guix build -L /tmp --with-inputs=r-minimal=r-minimal@3.4.3 r-rcpp

but because r-minimal is an implicit inputs, it is not re-written.

This behaviour is expected because the bag is really huge. To be
convinced, try: "guix graph -t bag r-rcpp | dot -Tps >
r-rcpp-bag.ps"... and wait... :-)


>From a practical point of view, re-write any implicit inputs is
touchy.  And I do not know if the "parametrized package" is related or
not at all -- I do not see real difference between re-compiling with
this flags and re-compiling with this version -- but be able to
recompile a matrix of combinaison would be really cool!


All the best,
simon