hello,
i'm developing an extension to Scheme
and i need a procedure or macro that define a variable only if it is not
bind and if it is just set! it.

I can not do it in Guile or any Scheme,and i'm desperately searching a way
to do that. I finally conclude that it can be done only by adding it in the
language.

Can someone include a such function in Guile next release?
i know guile have a predicate defined? to test binfing of a vairable but
writing a macro with it is not possible because define can be used in an
expression context.

Thank in advance for any help
Damien