Re: Lexical binding and macros.

[Elena <egarrulo@gmail.com>]

On Dec 15, 5:16 pm, David Kastrup <d...@gnu.org> wrote:
> Stefan Monnier <monn...@iro.umontreal.ca> writes:
> >> Do they still leak memory?  Fromhttp://c2.com/cgi/wiki?EmacsLisp:
>
> >> "Note that variables bound with lexical-let are never released, even
> >> if they are never used. Try
>
> >>  (loop for i from 1 to 100000 collect (lexical-let ((x i)) '()))
>
> >> and watch it eat memory. So making infinity (ZeroOneInfinity) lexical
> >> variables is out of the question except for very small values of
> >> infinity."
>
> > Additionally to what Pascal already explained, I'll add that,
> > lexical-let, like `loop' are relatively heavy macros, so you definitely
> > don't want to run them interpreted (where the macro is re-expanded each
> > time).
>
> Why would they be reexpanded each time?  They are macros.  Their
> expansion is done once and merely evalled each time.

Macros expansion can change if such macros depend on some other macros
which have been redefined after last expansion.