[r6rs-discuss] Interpreters need not apply?

[Aubrey Jaffer]

 | From: Pascal Costanza <pc at p-cos.net>
 | Date: Wed, 7 Mar 2007 16:05:53 +0100
 | 
 | On 7 Mar 2007, at 15:51, AndrevanTonder wrote:
 | 
 | > On Wed, 7 Mar 2007, Pascal Costanza wrote:
 | >
 | >> The terms "compiler" and "interpreter" are not well-defined. But
 | >> AFAICT, a compiler typically works in two phases: A translation
 | >> from one representation to another one, where the latter is
 | >> typically a representation that can be executed by some
 | >> interpreter (for example, a CPU).
 | >
 | > No r5rs-conformant Scheme interpreter will start evaluating a
 | > form without macro-expanding it first.  R6RS requires nothing
 | > more than this.
 | 
 | Here is an example:
 | 
 | (if expression form1 form2)
 | 
 | Assume that both form1 and form2 are macro invocations.  Will form1
 | and form2 both be macroexpanded before the if statement is
 | evaluated, or will first the expression be evaluated and depending
 | on its outcome only either form1 or form2 be expanded and then
 | evaluated?

In SCM, only form1 or form2 will be expanded and evaluated.