[plt-scheme] Re: [Larceny-users] side effects in R6RS modules

From: Abdulaziz Ghuloum (aghuloum at gmail.com)
Date: Tue May 5 11:21:20 EDT 2009

On May 5, 2009, at 5:44 PM, Matthias Felleisen wrote:

> In PL, such questions should be decided via mathematical models that
> do not depend on machines and compilers. That's the only way to truly
> disambiguate the English in a spec.
> For whatever reasons, the editors moved the only piece of mathematics
> semantics (which doesn't include modules and macros) to the appendix,
> for reasons that still escape me. Well, they don't really. If you
> don't have a tool for arbitrating two distinct interpretations of
> an informal document, you can always claim that both are correct and
> if you so desire, you can claim one of them is, eh, smart? :-)

Such tool helps indeed, but it's not the only way to arbitrate
the different interpretations of the document.  As a matter of
fact, the document in question explicitly states that both of
these interpretations (and many others) are allowed and are
correct with regard to satisfying the report's requirements.
The issue here is that the library in question has nonportable
semantics (as should be clear from reading the document) but
this is the same as depending on any other unspecified behavior
(such as one implementation's evaluation order: left-to-right,
right-to-left, ...).  You're not arguing that there must be
only one valid and true interpretation of the report, right?


Posted on the users mailing list.