Re: Found a bug in guile 1.6.0

[Marius Vollmer]

Roland Orre <address@hidden> writes:

> I found a bug when a let clause only contains a macro.
> When the clause also contains a lambda clause it works.

I don't think this is a bug in Guile, but a bug in the way you are
using procedure->macro.

The best solution is not to use procedure->macro.  Use define-macro
(or defmacro) or define-syntax.

'procedure->macro' does not generate what you probably think it does.
It creates a "non-memoizing macro", which is expanded everytime it is
executed.  The second time thru, tho, 'x' contains the internal form
of the macro invocation, which is not something that 'car' etc know
how to access.

You could try

  (define-macro (push! stack obj)
    `(set! ,stack (cons ,obj ,stack)))

but note that 'stack' is evaluated twice, which matters when you use
non-trivial setters/getters.

(Just curious: where did you learn about procedure->macro?  we don't
want people to use it.)

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