Re: [Scheme-reports] multiple values module

[John Cowan <cowan@x>]

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@x
        --Cordwainer Smith, Norstrilia

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