[plt-scheme] hash-has-key?

On Sat, 28 Mar 2009 10:07:50 -0400
Dave Herman <dherman at ccs.neu.edu> wrote:

> Matthias Felleisen:
> > Because Typed Scheme is typed, it's not possible for hash-ref to
> > use one standard "not found" type, so the API ought to provide the  
> > return type.
> 
> I don't know what this means.

I guess Matthias wanted to point out that being untyped or typed does
not help as there is no standard "not found" value/type either way.

regards,
Marek