[Scheme-reports] Formal comment: The denotational semantics Michael Sperber 24 Jun 2012 16:02 UTC

Formal Comment

the submitter's name: Michael Sperber
The submitter's email address: sperber@deinprogramm.de
the draft version of the report: draft 6
a one-sentence summary of the issue: The denotational semantics is inadequate
a full description of the issue:

The denotational semantics in the draft, which seems to be copied from
R5RS, is inadequate for helping to describe those parts of the semantics
where the semantics is especially tricky, especially evaluation order
and `dynamic-wind'.  This is a pity, especially as there's an R5RS
version of the semantics in R6RS:

http://www.cs.uchicago.edu/~jacobm/pubs/scheme-semantics.pdf

Moreover, there is a version of the denotational semantics that does
include `dynamic-wind' in this paper:

Martin Gasbichler, Eric Knauel, Michael Sperber Richard A. Kelsey: How
to Add Threads to a Sequential Language Without Getting Tangled Up, In
The 2003 Scheme Workshop, Boston, Ma., October 2003.

http://www.deinprogramm.de/sperber/papers/adding-threads.pdf

(I'd be happy to supply LaTeX if anybody is interested.)

PS: This is a general issue with the draft - the R6RS document contains
many improvements of the description of the language that are not about
changes in the language.  (To name two other prominent examples: the
distinction and relationship between numbers and the objects that
represent them, and the description of the syntax with respect to
macros.  Especially embarrassing is the pointer to the Indiana Scheme
repository, which has not been maintained for something like 14 years.)
Many parts of R7RS are throwbacks to the old, inferior wording.

--
Regards,
Mike

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