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From: brian@granite.jpl.nasa.gov (Brian of ASTD-CP)
Newsgroups: comp.lang.scheme
Subject: Re: Macros
Summary: Have Cake and Eat It Too
Keywords: macro, extend-syntax, lexical scope, standards
Message-ID: <1991May29.182453.24864@jato.jpl.nasa.gov>
Date: 29 May 91 18:24:53 GMT
References: <1490@yoakum.cs.utexas.edu>
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Reply-To: brian@granite.Jpl.Nasa.Gov (Brian of ASTD-CP)
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In article <1490@yoakum.cs.utexas.edu> wilson@cs.utexas.edu (Paul Wilson) writes:
>I respectfully differ with the "open letter" about Scheme.  In particular,
>macros *must* be standardized if Scheme is to survive.  Of all the
>barriers to using Scheme, this one's probably the easiest to fix.
>
    I think one of the main points of the letter was that
    Scheme ought to have standardized, but optional bits.
    Suppose macros were one such "standardized, but optional"
    facility.  Let us add the requirement that "standardized,
    but optional" facilities should be implementable in
    portable Scheme.  It so happens that facilities like
    "extend-syntax" and "defmacro" can be so implemented, and
    there are probably implementations available in the Scheme
    repository (I'll check nexus.yorku.ca in a bit).  So, 
    whatever the standards committee agrees on will end up
    being easily implementable if not freely available.

    So, by following the proscriptions of the letter, we get
    to have our cake and eat it too.  Implementors of Scheme
    can have a small job to do by implementing the "core"
    essential language.  Then users can just download
    implementations of the standard, but optional bits that the
    implementor might not have provided.


    

 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
 . . Brian Beckman . . . . . . . . . . brian@granite.jpl.nasa.gov. . . .
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