[plt-scheme] Re: Is R6RS useless for PLT?

From: Sam TH (samth at ccs.neu.edu)
Date: Tue Nov 25 09:10:49 EST 2008

On Tue, Nov 25, 2008 at 5:37 AM, Tom Gordon
<thomas.gordon at fokus.fraunhofer.de> wrote:
> Dear Grant,
>> Look at PLT, though, it support a *lot* of dialects. That is the
>> philosophy behind it. The philosophy is
>> not to push one single philosophy.
> I think this philosophy is really great for two purposes: 1) providing
> support for legacy code, and 2) experimenting with new dialects which can
> help us to gain the experience need to evolve the standard further.
> What I'm not too happy about, is the choice of the PLT team to develop and
> publish a new Scheme dialect which overlaps with R6RS, rather than building
> on or extending it, just *after* R6RS became ratified.    I would much have
> prefered that  R6RS had first been given a longer period of time to become
> established and waited a bit for feedback from users on their experiences
> with using R6RS, and use this feedback to build experimental extensions to
> R6RS which are feed into the development of R7RS.

PLT Scheme was not created new just after the R6RS.  PLT version 4
makes some minor and some major changes to the language, but it is
fundamentally the same language that it has been for many years.

>> All of the maintainers have their own interests in particular dialects
>> that meet their needs (Typed, HtDP, #scheme...), so it is unfair of us
>> to expect them to push a single dialect. That is just not the spirit
>> of Scheme, anyway.
> HtDP needs to be supported, because it is used for courses and one can't
> expect the book to be rewritten anytime soon. Fine.
> Type Scheme is a nice experimental language.  I really appreciate this
> effort.  But I would have appreciated it even more if it had been developed
> as an extension of R6RS.

I hope you appreciate that this is not actually possible.  Please see
my paper with Ryan Culpepper and Matthew Flatt in the Scheme Workshop
last year for the implementation details, very few of which can be
done in R6RS.

sam th
samth at ccs.neu.edu

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