[r6rs-discuss] "Unspecified"

[John Cowan]

Sam TH scripsit:

> That is, should (if #f #f) return a particular value, or not.  It seems
> that the current name for the value returned by that expression is a
> compromise between those who want the result to be genuinely
> unspecified, and those who want a particular value.  

Indeed.  It seems, however, that all Schemes (exceptions?) actually do
provide a particular value, and that that value might as well be
standardized.

> Once this question is resolved, the other questions seem much easier,
> and mostly just a question of naming.  The value could be named void, or
> unit, or nil, or empty, or no-information, with appropriate
> constructors, predicates, external representations.  

I'd say the only remaining question of substance is whether to have an
external representation or not.

-- 
John  Cowan  http://ccil.org/~cowan   cowan at ccil.org
'My young friend, if you do not now, immediately and instantly, pull
as hard as ever you can, it is my opinion that your acquaintance in the
large-pattern leather ulster' (and by this he meant the Crocodile) 'will
jerk you into yonder limpid stream before you can say Jack Robinson.'
        --the Bi-Coloured-Python-Rock-Snake