retitle 37461 Methods added to primitive generics don't always work thanks Rob Browning <r...@defaultvalue.org> writes:
> A re-export doesn't affect the module using the re-exporter, and export > and replace both fail with "Unbound variable: equal?", even though > there's a (define equal? ...) in the module. It looks like equal? isn't changed by define-generic, etc. because it already has "generic-capability?". And in fact, I can see that defining a method on it does alter its primitive-generic-generic, but then dispatch to the new method doesn't always seem to work (or perhaps I just misunderstand the dispatch rules). Here a one argument specialization doesn't work, but a two argument specialization does -- for new classes, but not for a "standard" class like <string>: scheme@(guile-user)> (use-modules (oop goops)) scheme@(guile-user)> (primitive-generic-generic equal?) $1 = #<<generic> equal? (1)> scheme@(guile-user)> (define-class <foo> () (data)) scheme@(guile-user)> (define-method (equal? (x <foo>)) 'x) scheme@(guile-user)> (primitive-generic-generic equal?) $2 = #<<generic> equal? (2)> scheme@(guile-user)> (equal? (make <foo>)) $3 = #t scheme@(guile-user)> (define-method (equal? (x <foo>) (y <foo>)) 'x) $4 = #<<generic> equal? (3)> scheme@(guile-user)> (equal? (make <foo>) (make <foo>)) $5 = x scheme@(guile-user)> (define-method (equal? (x <string>) (y <string>)) 'x) $6 = #<<generic> equal? (4)> scheme@(guile-user)> (equal? "x" "y") $7 = #f Thanks -- Rob Browning rlb @defaultvalue.org and @debian.org GPG as of 2011-07-10 E6A9 DA3C C9FD 1FF8 C676 D2C4 C0F0 39E9 ED1B 597A GPG as of 2002-11-03 14DD 432F AE39 534D B592 F9A0 25C8 D377 8C7E 73A4
