Re: Macro expansion: Why doesn't the invoked macro see (let (variables)) from the invoking one?

[Tassilo Horn]

Alan Mackenzie <address@hidden> writes:

Hi Alan,

> One macro FOO binds a let variable, then invokes another macro BAR.
> BAR doesn't see this let variable.  Why not?  Is there anything I can
> do about this?
>
> (defmacro BAR ()
>   (message (if (boundp 'asdf) "asdf" "no asdf"))
>   '(message "bar"))
>
> (defmacro FOO ()
>   (let (asdf)
>     `(BAR)))

It seems first (FOO) expands into (BAR) and at that time asdf is bound,
but then the expansion of (BAR) is again isolated.

It looks like try to create a macro that creates a different expansion
depending on its context.  I don't think that's a good idea anyway.
Better add an explicit asdf parameter.

Bye,
Tassilo