[r6rs-discuss] Unicode issues
lord at emf.net
Wed Aug 29 23:00:41 EDT 2007
Aubrey Jaffer wrote:
> Not so! If you use records to specify the new type, then EQV? won't
> work on these new characters. States r5.97rs-lib section 6.1
> Mutability and equivalence of records:
> * If obj1 and obj2 are both records of the same record type, and
> are the results of two separate calls to record constructors, then
> eqv? returns #f.
Oh my goodness. That's very, very bad. That reifies an execution
model in a particularly unforgivable way.
I was just thinking, earlier today, that R6 blows it by introducing
intentional types when the only real demand was for user-defined
disjoint types. I was thinking of libraries but the same design
pattern issue relates to records.
New rule: shun opaque types! Extensional types only!
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