🚀 go-pugleaf

rick@tetrauk.UUCP (Rick Jones) writes:

>The real issue is not that the solution can't be type-checked, it's that the
>problem itself doesn't type-check.

This is not true - unless we have different understandings of what
"type-check" means.  For me, a program "type-checks" statically (is
type-safe) iff you can prove, from the text of the program alone, that
no "message not understood" errors will occur at run-time, i.e. that
no interfaces are violated.  As explained in an earlier posting, the
example *does* type-check in this sense.

>Please note that I'm not flaming dynamic typing as a concept, it has many
>points in its favour.  What I would say is that any well-engineered design
>should in principle be statically type checkable, even if you choose to
>implement it in a dynamically typed language.

I agree with you 100%.  My point is that today's type systems disallow
many legal (type-safe) programs because they are just too restricted
(the type systems, not the programs ;-).

-Urs
-- 
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Urs Hoelzle                                            hoelzle@cs.stanford.EDU
Center for Integrated Systems, CIS 42, Stanford University, Stanford, CA 94305