Hi all, hi Matthias,
I would like to come back to my (still unsolved) problem I
proposed some days ago:
when using define-syntax in a inner scope of bindings (like let),
in this example:
(define-syntax mymacro
(syntax-rules ()
[(_ x)
(eval `(lambda (w) (print (quote x)) (if x w #f)))]))
(let* ((s 3) (f (mymacro (> s 0)))) (f 5))
reference to undefined identifier: s
of course if you:
(define s 3)
in the top environment, the error will not appear.
This is even more clear if you expand the macro:
(syntax->datum (expand '(mymacro (> s 0))))
... you see that "s" is a %top binding.
I know that if I make the macro to return directly the lambda,
it works. Nevertheless, in my implementation, I still need to use
the "(eval (quasiquote (lambda ...)))".
Why? my macro is like a compiler
that generates a lambda code very huge: the code is recursive in some of
its part,
but, for efficiency reasons, i preferred to inline all recursive calls. So I
use a
function "expander" that makes recursive inlining (or injecting) of code).
It is more or less something like:
`(lambda (...) ... static-code... ,(expander ...) ...)
where "expander call itself with different parameters.
This is just to know your opinion... if the "(eval (quasiquote (lambda
...)))"
cannot see local bindings like in let*, than I have to choice:
1) renounce to the feature.
2) looking for alternative methods to generate my code with recursive
inlining
Than you,
Cheers,
Maurizio.
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