[plt-scheme] Mutable and immutable pairs in PLT Scheme

From: Tom Gordon (thomas.gordon at fokus.fraunhofer.de)
Date: Wed Nov 26 10:14:12 EST 2008

On Nov 26, 2008, at 3:49 PM, Matthew Flatt wrote:

>> While I can't claim any Scheme implementation (#3) or programming
>> language design experience (#2) when it comes to this topic, it does
>> seem pretty clear to me that taking this step would create a  
>> marketing
>> nightmare for PLT.
> Well, the Scheme community being what it is, most any significant
> action creates PR and diplomacy problems. We can deal with them,
> though, if the action is otherwise useful enough.
> So, to help gauge usefulness for this potential action, I'll revise  
> the
> question:
> Does anyone actually use (and expect to continue to use) the `(rnrs
> mutable-pairs)' library in PLT Scheme's R6RS?

Our Carneades system <http://carneades.berlios.de> uses the following  
libraries which import and use the (rnrs mutable-pairs) library:

1. Alex Shinns' portable hygenic pattern matcher
2. Dorai Sitaram's portable regular expressions library
3. Busch, Holm, and Dickey's Portable Scheme Interface to the Tk GUI  
4. Olin Shiver's SRFI-1 List Processing Library
5. Ray Dillinger's implementations of "write-with-shared-structure"  
and "read-with-structure" for Larceny and Ypsilon, which is part of  
his port of various SRFI's to R6RS.
6. Philip Bewig's R6RS implementation of the SRFI-41 stream library.

Nonetheless, we are in favor of this idea.  We would much prefer  
greater interoperability with the rest of PLT Scheme to retaining  
support for the (rnrs mutable-pairs) library, even though this would  
sacrifice some conformance with the standard.

We are willing try to modify the libraries we use, listed above, to  
remove their dependencies on mutable pairs, in collaboration with  
their authors.


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