X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=doc%2Fmanual%2Fbeyond-ansi.texinfo;h=c79ee95b79173a7caa617a6c2bb7fe4bc42cfea3;hb=d4d6c4b16a3655ce99a87d43f411391363531260;hp=2cde567622adc790b697f628348896afe9e0d5e2;hpb=9ce24dc604859d2670a989da2a9015b67c37e00f;p=sbcl.git diff --git a/doc/manual/beyond-ansi.texinfo b/doc/manual/beyond-ansi.texinfo index 2cde567..c79ee95 100644 --- a/doc/manual/beyond-ansi.texinfo +++ b/doc/manual/beyond-ansi.texinfo @@ -48,6 +48,7 @@ are: @findex compute-effective-method @findex sb-mop:compute-effective-method @code{compute-effective-method} only returns one value, not two. + There is no record of what the second return value was meant to indicate, and apparently no clients for it. @@ -60,6 +61,10 @@ the arguments @code{:declare} and @code{:declarations} to argument defining the declarations to be stored and returned by @code{generic-function-declarations}. +Where AMOP specifies @code{:declarations} as the keyword argument to +@code{ensure-generic-function}, the Common Lisp standard specifies +@code{:declare}. Portable code should use @code{:declare}. + @item @findex validate-superclass @findex finalize-inheritance @@ -69,6 +74,8 @@ argument defining the declarations to be stored and returned by @tindex funcallable-standard-class @tindex sb-mop:funcallable-standard-class @tindex function +@findex sb-mop:class-prototype +@findex class-prototype although SBCL obeys the requirement in AMOP for @code{validate-superclass} for @code{standard-class} and @code{funcallable-standard-class} to be compatible metaclasses, we @@ -77,6 +84,40 @@ of metaclass @code{funcallable-standard-class} must have @code{function} in its superclasses, and a class of metaclass @code{standard-class} must not. +@findex typep +@findex class-of +@findex subtypep +At class finalization, a class prototype which is accessible by a +standard mop function @code{sb-mop:class-prototype}. The user can +then ask whether this object is a @code{function} or not in several +different ways: whether it is a function according to @code{typep}; +whether its @code{class-of} is @code{subtypep} @code{function}, or +whether @code{function} appears in the superclasses of the class. The +additional consistency requirement comes from the desire to make all +of these answers the same. + +The following class definitions are bad, and will lead to errors +either immediately or if an instance is created: +@lisp +(defclass bad-object (funcallable-standard-object) + () + (:metaclass standard-class)) +@end lisp +@lisp +(defclass bad-funcallable-object (standard-object) + () + (:metaclass funcallable-standard-class)) +@end lisp +The following definition is acceptable: +@lisp +(defclass mixin () + ((slot :initarg slot))) +(defclass funcallable-object (funcallable-standard-object mixin) + () + (:metaclass funcallable-standard-class)) +@end lisp +and leads to a class whose instances are funcallable and have one slot. + @end itemize @node Support For Unix