Re: possible bug while exporting generics

[Ludovic Courtès]

Hi,

(No need to post to both lists.)

schemer <address@hidden> writes:

> ;; ------------------------------
> ;; file a.scm
> (define-module (a)
>   #:use-module (oop goops)
>   #:duplicates merge-generics)
>
> (define-class <a> ()
>   (a
>    #:init-value 0
>    #:getter /val))
>
> (export <a> /val)
>
> ;; -------------------
> ;; file ab.scm
> (define-module (ab)
>   #:use-module (oop goops)
>   #:use-module (a)
>   #:use-module (ice-9 pretty-print)
>   #:duplicates merge-generics)
>
> (define-class <ab> ()
>   (ab
>    #:init-value 0
>    #:getter /val))
>
> (pretty-print (generic-function-methods /val))
>
> (export /val <ab>)

Guile's behavior is admittedly unclear, but your example is wrong:
module `(ab)' shouldn't export `/val' since it is just adding a new
method to the existing generic bound to `/val'.  Thus it should either,
not export it, or just re-export it:

===File ~/tmp/guilish/ab.scm================================
;; -------------------
;; file ab.scm
(define-module (ab)
  #:use-module (oop goops)
  #:use-module (a)
  #:use-module (ice-9 pretty-print))

(define-class <ab> ()
  (ab
   #:init-value 0
   #:getter /val))

(pretty-print (generic-function-methods /val))

(export <ab>)
(re-export /val)
============================================================

This fixes the problem:

  $ guile -L .
  guile>  (module-ref (resolve-module '(ab)) '/val)
  (#<<accessor-method> (<ab>) b72cc200>
   #<<accessor-method> (<a>) b72daf00>)
  #<<generic> /val (2)>

Thanks,
Ludovic.