[r6rs-discuss] On naming the next scheme(s) [was scheme-reports.org]

[Peter Bex]

On Mon, Aug 24, 2009 at 10:57:44AM -0500, Brian Mastenbrook wrote:
> `syntax-rules' is much easier to implement than the standard low-level  
> macro system from R6RS, as the underling implementation methodology is  
> left up to the choice of the implementor.

Syntax-case is considered to be a high-level macro system.  As far as I
know, R6RS *has* no low-level macro system.
 
> If you're thinking of  
> unhygienic macros, I think this would be a horrible idea; lexical  
> scoping of *all* identifiers, including those in syntax definitions,  
> is central to the Scheme idea.

Not necessarily.  I think all low-level systems allow for breaking of
hygiene, but that's not the reason to prefer a low-level system.
A low-level system is useful because it allows one to explain macros
in terms of familiar Scheme primitives as cons, car and cdr.
This simplicity fits well with Scheme, and I think it would also serve
well in an educational setting - having to explain that high-level
macro systems are their own language separate from Scheme is yet another
layer of complexity.

Cheers,
Peter
-- 
http://sjamaan.ath.cx
--
"The process of preparing programs for a digital computer
 is especially attractive, not only because it can be economically
 and scientifically rewarding, but also because it can be an aesthetic
 experience much like composing poetry or music."
							-- Donald Knuth
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