Re: Fmt Module

[Andreas Rottmann]

address@hidden (Ludovic Courtès) writes:

> Hello,
>
> Andreas Rottmann <address@hidden> writes:
>
>> Not that I have any say in that, but IMHO, it would be preferable to
>> keep external libraries maintained separatly from the Guile core;
>> however in this case, including it in the core might be justified by its
>> proposed use in the JIT compiler.
>
> When we do include external libs, we should strive to leave upstream
> files unmodified, as is done for (sxml ssax), (system base lalr),
> (ice-9 match), and others.
>
As I already mentioned, the Wak adaption of `fmt' does not modify
upstream files (except for the test suite); it is just adding library
definition files that include the upstream files.  As wak-fmt seems to
work nicely on Guile, I see no problem here.

> I think it would make sense to include ‘fmt’ in core Guile only if the
> API is reasonably stable and there are infrequent upstream releases, so
> we don’t quickly end up shipping an old incompatible version.
>
I think `fmt' qualifies these criteria.

However, even if I think based on your criteria nothing speaks against
including fmt in Guile, there is still the argument of code duplication:
if some external library (e.g., conjure) makes use of wak-fmt and
another chooses the version included in Guile, a third program/library
can't make use of both of these without ending up with two copies of the
`fmt' code loaded, incurring a load-time and memory usage overhead.
Obviously, there's also duplicated work involved in maintaining the
different adaptions of the `fmt' code.  

I think the ideal solution would be to move the R6RS library definitions
upstream, but I don't think that's realistic just yet, as (a) there's no
built-in `include' in R6RS (I think R7RS will fix that), so an `include'
implementation would either have to be shipped, again resulting in code
duplication with other libraries (as `include' is portably implementable
in R6RS), and (b) there's not yet a real, entrenched standard for naming
of R6RS library files (which again might be fixed by R7RS, and could in
the meantime be mitigated by a package manager such as dorodango,
although implementation-specific library<->file name mapping is not yet
implemented).

Even given all that, if some core component of Guile itself (e.g., a VM
code generator) wants to make use of `fmt', there's probably no way
around shipping a copy in core Guile itself.

Just my 0.02€
-- 
Andreas Rottmann -- <http://rotty.yi.org/>