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Re: Specification

This page is part of the web mail archives of SRFI 93 from before July 7th, 2015. The new archives for SRFI 93 contain all messages, not just those from before July 7th, 2015.

On 6/26/06, Andre van Tonder <andre@xxxxxxxxxxxxxxxxx> wrote:

I like the operational semantics in the SRFI, since it may be less ambiguous
than the alternative declarative approach.

As corrobrating evidence, I can mention the syntax-case implementation in
SRFI-72.  That implementation satisfies declarative descriptions of
hygiene.  However, the implementation technique is based on an "implicitized"
version of explicit renaming, not marking/substitution.  There are some highly
obscure corner cases where it behaves differently from the marking algorithm,
while still satisfying hygiene.  I have to recheck, but I think these
ambiguities should be resolved by specifying the algorithm as is
done here (though perhaps a little more detail might be required).

I think the trick is to make an unambiguous declarative specification.