>> A side issue: I feel that the `install-file' procedure should print out
>> what it's doing to stdout (or some log port). Something like:
>>
>> (format #t "~a -> ~a~%" source destination)
>>
>> This would save us the trouble of implementing this log printing
>> everywhere `install-file' is called. For example, this could be very
>> useful in the 'install' phase of the font-build-sytem. WDYT?
>
> Do we really need to print something in the first place?  :-)  Some
> procedures in (guix build utils) do that, indeed, but I’m not sure it’s
> useful for something as simple as ‘install-file’.  Thoughts?

Yes, I think it is really important. Without the verbose output, one
will have to stare at a blank screen, guessing at what is
happening. Long verbose output feels reassuring that something is going
on. :-) Also, verbose output for `install-file' might help in debugging
correct source/destination paths.

>> The patches migrating the font packages to the font-build-system are not
>> properly complete. I'll send them in after more work. For now, please
>> find attached the patch for the font-build-system alone.

The four font packages (inconsolata, dejavu, ubuntu and bitstream-vera)
are also ready.

>> * Makefile.am (MODULES): Add 'guix/build-system/font.scm' and
>>   'guix/build/font-build-system.scm'.
>> * guix/build-system/font.scm: New file.
>> * guix/build/font-build-system.scm: New file.
>
> Please mention guix.texi as well.

Done!

>> +@defvr {Scheme Variable} font-build-system
>> +This variable is exported by @code{(guix build-system font)}.  It
>> +implements an installation procedure for font packages.  It copies font
>                                                          ^
> I’d write:
>
>   … for font packages where upstream provides pre-compiled TrueType,
>   OpenType, etc. font files that merely need to be copied into place
>
> This is to distinguish from fonts that we build from a FontForge
> (whatever it’s called today) source.

Done!

>> +                   ,@(let ((compression (resolve-module '(gnu packages compression))))
>> +                       (map (match-lambda
>> +                              ((name package)
>> +                               (list name (module-ref compression package))))
>> +                            `(("tar" tar)
>> +                              ("gzip" gzip)
>> +                              ("bzip2" bzip2)
>> +                              ("xz" xz))))))
>
> This works, but since ‘tar’ is defined in (gnu packages base), it’s
> better to take it from there.

Done! I have also included "unzip" because several font packages come as
zip archives. WDYT?

> Also, prefer ‘resolve-interface’ over ‘resolve-module’: the former
> provides access to public/exported bindings only, whereas the latter
> provides access to both public and private bindings.

Done!

> Do some of the candidate packages provide Type1 fonts?  If not, this is
> perfect; if we do, then in a future patch we can extend it to support
> Type1 as well.

I haven't come across Type1 fonts yet. After pushing these patches
(after I hear your thoughts on "unzip"), I'll start migrating the other
font packages. When I come across Type1 fonts, I'll extend the
font-build-system as well.