[plt-scheme] Are macros a programming language?

A programming language can be defined as a system consisting of two sets:
1: (a set of rules defining) a set of well formed expressions
2: a set of contraction rules defining the evaluation process
A syntax is not a pair of sets and hence is not a programming language.
The set of all macros isn't a language either.
However, every macro and set of macros defines a language when regarding the 
expansion as an evaluation.
Jos Koot

((((lambda(x)((((((x x)x)x)x)x)x))
   (lambda(x)(lambda(y)(x(x y)))))
  (lambda(x)(write x)x))
 'greeting)
----- Original Message ----- 
From: "Grant Rettke" <grettke at acm.org>
To: "PLT Scheme List" <plt-scheme at list.cs.brown.edu>
Sent: Sunday, October 21, 2007 6:39 AM
Subject: [plt-scheme] Are macros a programming language?


> Macros are not Scheme, so what are they?
>
> Are they are programming language?
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