Re: Problem merging generics across modules

[David Pirotte <david@altosw.be>]

[-- Attachment #1: Type: text/plain, Size: 2180 bytes --]

Hi Andrew,

	Lets try to keep our conversation about this o the list, others may benefit
	from it, and/or help us ...

> Thanks for your feedback on this. It certainly resolved my issue.

Welcome.

> Can you point me to documentation on this? I read through the Guile info
> pages when trying to figure this out, but I couldn't figure it out.
> ...

No, there is no 'good' documentation neither recommendation(s) about 'generic
functions and the module system' in guile's manual - I mean 'no good' in my opinion,
but this is 'relative', and besides, some guilers are opposed to these
recommendations I always 'offer', but here they are:

1]	better preventing then curing:  when you define a module that use goops,
	always use

  #:duplicates (merge-generics
		replace
		warn-override-core
		warn
		last)

2]	unless you really know what you are doing, never call define-generic
	yourself

3]	always use #:export for class names, and make sure class names are
	unique (guile will warn you if not, at import time, so rename if you
	have conflict, never use twice the same class name in diff modules (unless
	you really know what you're doing))

4]	always use g-export for (and only for) getters, setters, accessors and
	methods

	https://git.savannah.gnu.org/cgit/guile-cv.git/tree/cv/support/g-export.scm

5]	remember, while you are developing and testing your code, you have to add
	'merge-generics to the default-duplicate-binding-handler in the repl as well,
	_after_ you imported goops (in the repl):

	,use (oop goops)
	(default-duplicate-binding-handler
	   '(merge-generics replace warn-override-core warn last))
	(use-modules (yourmod1) (yourmod2))

With these recommendations, you actually 'mimic' [1] the CLOS specification, which
states that anything related to CLOS lands in a specific package, visible to all
others.

David

[1]	mimic because unlike CLOS, a generic function in a guile module will
	only contain methods that comes from that module and the one it
	imports, but not (necessarily) all methods for that name (unless the module
	imports all the others that define a method for that name of course)

[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 488 bytes --]