On Mon, 15 Aug 2005, Marcin 'Qrczak' Kowalczyk wrote:

> Andre van Tonder <xxxxxx@now.het.brown.edu> writes:
>
>> For each identifier, the expander needs to keep track of its binding
>> at all different levels of the syntactic tower.
>
> I would say: for each level of the syntactic tower, the expander needs
> to keep track of bindings of all identifiers there.

Certainly.  What I meant is that when a macro introduces an identifier, it does
not know at what syntactic level the identifier will be used in the completely
expanded expression.  So it has to attach all the possible bindings as part of
the representation of the identifier.

Cheers
Andre