Re: [Chicken-users] Redefining macros and special forms

[John Cowan]

Peter Bex scripsit:

> This inconsistency could be considered a bug: if a new identifier is
> introduced at the toplevel which "shadows" a macro, it could erase the
> macro.  It's not a priority because the spec doesn't really say what to
> do, and the responses of various Schemes differ in this.  Gambit for
> example even disallows redefining macro definitions:
> 
> > (define begin -)
> *** ERROR IN (console)@1.9 -- Macro name can't be used as a variable: begin

Gambit is inconsistent in its inconsistency.  It will allow you to fully
override a macro name, but not a built-in syntax keyword such as begin
or cond.

> But yeah, many other Schemes simply replace the macro definition by the
> procedure.  

The only ones that don't (from my test suite) are Chicken, Bigloo,
STklos, and Picrin.  I have filed a bug against Picrin, since it is an
R7RS Scheme and R7RS doesn't permit this behavior.

-- 
John Cowan          http://www.ccil.org/~cowan        address@hidden
Time alone is real
  the rest imaginary
like a quaternion       --phma