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

From: Tom Gordon (thomas.gordon at fokus.fraunhofer.de)
Date: Thu Nov 27 05:20:02 EST 2008

Alex -

I accept your point that R6RS is missing a single function ("process")  
needed to implement PSTK.  By "porting to R6RS", I mean only writing  
as much code as possible in R6RS and to isolating system-dependent  
code in specific libraries.

> I didn't mean to attack R6RS so much as to point out a very serious  
> limitation in what it can achieve portably.

While we agree there are liimitations to how much code can be portably  
expressed in pure R6RS, or any other Scheme for that matter,
I can't agree with your suggestion that its no easier to achieve  
portability in R6RS than R5RS.  R6RS's library system and larger set  
of standard libraries are very helpful, not to mention having a  
standard for records, exception handling, unicode, and more.

> In the context of the overall complaint (that code written  
> specifically for PLT is not portable) this is highly relevant.

Here you've lost me.  Isn't code written specifically for PLT almost  
by definition not portable?   At least a significant manual effort is  
required to port the code.  Are you suggesting it is no more difficult  
to port programs from the PLT dialect of scheme to (other) R6RS  
implementations than to port a programs written in R6RS, to the extent  
possible, from one R6RS implementation to another?  This hardly seems  
plausible to me.


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