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

From: Alex Shinn (alexshinn at gmail.com)
Date: Thu Nov 27 03:47:37 EST 2008

Abdulaziz Ghuloum <aghuloum at cs.indiana.edu> writes:

> 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.

No, he didn't.  He had to write several versions for each
implementation, which is why the source contains:

  scheme/src/carneades/lib/pstk/system.ikarus.sls
  scheme/src/carneades/lib/pstk/system.mzscheme.sls
  scheme/src/carneades/lib/pstk/system.ypsilon.sls

R6RS implementers could in theory work together to agree on
a common inter-process communication library, but the
implementation itself would still not be portable - this is
exactly the scenario we have with R5RS and SRFIs.

I didn't mean to attack R6RS so much as to point out a very
serious limitation in what it can achieve portably.  In the
context of the overall complaint (that code written
specifically for PLT is not portable) this is highly
relevant.

-- 
Alex


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