X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=doc%2Fmanual%2Fbeyond-ansi.texinfo;h=c79ee95b79173a7caa617a6c2bb7fe4bc42cfea3;hb=d4d6c4b16a3655ce99a87d43f411391363531260;hp=6e44f7defe177a27b2117bca11b829bdc88e3a6e;hpb=d29b504c51bc69b3ea2eff8cdeaae4f7c9614b72;p=sbcl.git diff --git a/doc/manual/beyond-ansi.texinfo b/doc/manual/beyond-ansi.texinfo index 6e44f7d..c79ee95 100644 --- a/doc/manual/beyond-ansi.texinfo +++ b/doc/manual/beyond-ansi.texinfo @@ -45,29 +45,13 @@ are: @itemize @item -@tindex metaobject -the abstract @code{metaobject} class is not present in the class -hierarchy; - -@item -@tindex standard-object -@tindex funcallable-standard-object -the @code{standard-object} and @code{funcallable-standard-object} -classes are disjoint; - -@item @findex compute-effective-method @findex sb-mop:compute-effective-method -@code{compute-effective-method} only returns one value, not two; - -@item -@findex compute-slots -@findex sb-mop:compute-slots -@tindex funcallable-standard-class -the system-supplied @code{:around} method for @code{compute-slots} -specialized on @code{funcallable-standard-class} does not respect the -requested order from a user-supplied primary 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. + @item @findex ensure-generic-function @findex generic-function-declarations @@ -77,6 +61,63 @@ 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 +@findex sb-mop:validate-superclass +@findex sb-mop:finalize-inheritance +@tindex standard-class +@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 +impose an additional requirement at class finalization time: a class +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