Re: Intended meaning

From: Michael Hanus <>
Date: Mon, 29 Oct 2007 12:47:38 +0100

Sergio Antoy wrote:
> It makes sense. However, the Curry Report may lead to believe
> differently. Section 3 allows a reduction in either argument of a
> disjunctive expression. Section 2.3.1 says that several
> occurrences of the same variable are always shared (in italic).

Thanks for showing up this inconsistency which is the result
of the development of the language definition over time.
The remark about the sharing of variables was introduced
when the language was extended to non-confluent rewrite
rules. As you have clearly shown, it is not conform with
the initial presentation of the operational semantics with disjunctive
expressions. In order to take account the developments
on the semantical side during the last years,
I would prefer to include a more precise description of the
language in the report: one declarative semantics specifying
what should be computed, e.g., in the form of the CRWL calculus,
and one non-deterministic operational semantics including sharing
and the needed narrowing strategy, e.g., in the form of the JSC'05
paper. This means that the presentation with disjunctive
expressions will be dropped.

What do you (or also others) think about this proposal?

Best regards,

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Received on Mo Okt 29 2007 - 13:04:59 CET

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