[r6rs-discuss] "Unspecified"

AndrevanTonder andre at het.brown.edu
Fri Sep 22 13:57:57 EDT 2006


On Fri, 22 Sep 2006, William D Clinger wrote:

> This problem could
> have been solved by requiring continuations that
> expect a single value to coerce zero values into
> an unspecified value, or into some specific value
> (e.g. the oxymoronic unspecified value), but the
> editors decided not to require that.

I don't quite understand why one would want this coercion
to happen.  It would seem to be more useful if an error
occurred - I refer to my problem of discovering #<unspecified>
values of obscure origin in a data structure and then having
the difficult task of figuring out which call in the history
of the computation could have caused them.

This is much less of a problem in a typed language like ML, but
in Scheme there is value in discovering these "type errors"
sooner rather than later.

Andre



More information about the r6rs-discuss mailing list