Re: [Scheme-reports] multiple values module
John Cowan 21 May 2011 20:49 UTC
Andre van Tonder scripsit:
> I prefer William Clinger's philosophy regarding standards, which can
> be found somewhere in the R6RS discussions. From memory, a standard
> posits a set of postulates that can be used to infer a set of portable
> programs. Not all programs allowed by an implementation need to be
> portable, but if the set of postulates is simple enough, it should be
> relatively easy to program in the portable sublanguage.
That sets a floor, but not a ceiling. How much should be standardized
and how much should not remains open. In ANSI C discussions, the
formula that a standard is a contract between users and implementers
was employed. This too is reasonable, but how many clauses should the
contract have? C prescribes that a short is no shorter than a char and
no longer than an int. Java prescribes that it is 16 bits. Both styles
have merit in their own contexts.
> Specifying that an unspecified value be returned by a command is a
> prime example of a a postulate that does not need to be added to the
> language specification.
But it *was* added and remains there. To change it, a majority of a
self-selected set (you, too, could have participated, and you and you
and you) had to decide to change it. They didn't.
--
All Norstrilians knew that humor was John Cowan
"pleasurable corrigible malfunction". cowan@ccil.org
--Cordwainer Smith, Norstrilia
_______________________________________________
Scheme-reports mailing list
Scheme-reports@scheme-reports.org
http://lists.scheme-reports.org/cgi-bin/mailman/listinfo/scheme-reports