[R6RS] Core/library split: `syntax-rules'
Anton van Straaten
anton at appsolutions.com
Thu Aug 3 12:50:08 EDT 2006
Michael Sperber wrote:
> Anton van Straaten <anton at appsolutions.com> writes:
>>>Shouldn't we have `syntax-rules' in the core?
>>Since there are already two essentially independent macro systems in
>>R6RS, and since implementations provide other systems, I didn't think
>>any single system should be imposed at that level.
> Independent? I thought `syntax-rules' is trivially defined in terms
> of `syntax-case'.
Defmacro is also trivially defined in terms of syntax-case...
> I see it as a simple more foolproof interface to
Sure. What I meant by "essentially independent" is that syntax-rules
can be, and has been, implemented independently of syntax-case.
The reason that's relevant here is that although it may make a lot of
sense to use syntax-case as the native macro system for an
implementation, other choices are also possible, particularly in light
of one of the R6RS guiding principles, "allow researchers to use the
language to explore the design, implementation, and semantics of
Requiring syntax-rules in the core makes less sense if an implementation
chooses to use something other than syntax-case as its native macro system.
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