[plt-scheme] Re: PLT R6RS questions and answers

From: Abdulaziz Ghuloum (aghuloum at cs.indiana.edu)
Date: Thu Nov 27 02:44:04 EST 2008

On Nov 27, 2008, at 1:47 AM, Alex Shinn wrote:

> Except you haven't ported PSTK to R6RS - that's
> fundamentally impossible since R6RS supports neither
> inter-process communication nor an FFI.

That's in theory, right.  In practice, he did.  That's
because the implementors of R6RS are working together on
having common conventions and de facto standards that go
beyond what R6RS requires in order to *allow* users the
opportunity to share code across implementations and at
the same time leverage the additional nonstandard (but
often overlapping) facilities provided by the individual
implementations.  Many consider that a step forward.

> Instead you have several files, one for each implementation.
> That's one way people achieve portability in R5RS.  For any
> large, practical application, it's no easier to achieve
> portability in R6RS than in R5RS, and the latter gives you a
> wider range of implementations to choose from (including
> PLT).

People who are interested in comparing the two approaches
can decide for themselves whether it's easier or not.  They
can look at the original PSTK code and see what one has to
do to make it run under one of the supported implementations
(e.g., look for the right sections to comment/uncomment) vs.
the new approach.

> You may argue that R6RS is a step in the direction of easier
> portability, but so far all it seems to have done is faction
> the community further.

Let's not go there please.  You are free to use or not to use
any implementation of any standard of Scheme as you please.
Making such sweeping remarks does not help your cause or mine.


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