On Tue, Aug 16, 2011 at 3:38 PM, David Kastrup <d...@gnu.org> wrote:
>
> Compile Lilypond with
> -DSCM_DEBUG_TYPING_STRICTNESS=2
>
> The guile documentation states quite clearly
>
> -- C Type: SCM
> `SCM' is the user level abstract C type that is used to represent
> all of Guile's Scheme objects, no matter what the Scheme object
> type is. No C operation except assignment is guaranteed to work
> with variables of type `SCM', so you should only use macros and
> functions to work with `SCM' values. Values are converted between
> C data types and the `SCM' type with utility functions and macros.
>
> Now the Lilypond code base is chock full of code comparing SCM values.
> And it likely also contains a number of cases where C types (like
> booleans) and Scheme type are getting mixed up.
The abstraction that guile uses is not that tight. I would start
worrying about this once the GUILE team starts actually using the
constraints mentioned in the above snippet. Given the current release
rate of Guile, I wouldn't be too worried.
> But with the current code base, cleaning this all up is going to be a
> lot of work. Not hard to do, but a lot.
The only real problem are boolean conversions because they are very wrong, ie,
SCM x = ...
if (x) {
..
}
for the rest, making lilypond SCM typing clean is just a lot of work
with no benefits at all.
(and I am speaking as a GUILE developer here as well)
--
Han-Wen Nienhuys - han...@xs4all.nl - http://www.xs4all.nl/~hanwen
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