Hellu!
>> Yes, you're right.
>> I even went a little further with that and now I also capture lexical
>> environment:
>> (use-modules (system syntax) (ice-9 local-eval))
>>
>> (define-macro (function args . body)
>> `(let ((environment (the-environment))
>> (lexical-names (lexical-names))
>> (procedure (lambda ,args ,@body)))
>> (set-procedure-property! procedure 'source '(function ,args ,@body))
>> (set-procedure-property! procedure 'environment environment)
>> (set-procedure-property! procedure 'lexical-names lexical-names)
>> procedure))
>>
>> (where ``lexical-names'' returns the car-s of ``lexicals'', as defined
>> at the bottom of
>> http://www.gnu.org/software/guile/manual/html_node/Syntax-Transformer-Helpers.html#Syntax-Transformer-Helpers
>> )
>>
>> So in addition to the source of the procedure, the lexical environment
>> can also be retrieved:
>>
>> (define (procedure-lexicals proc)
>> (map (lambda(symbol)
>> (cons symbol
>> (local-eval symbol (procedure-property proc 'environment))))
>> (procedure-property proc 'lexical-names)))
>
> I don’t want to sound too dogmatic, but I think you really don’t want to
> take that route. ;-)
>
> The issues with ‘local-eval’ have been discussed at length a year ago or
> so on guile-devel. Basically, the problem is that it plays badly with
> compilation, and there are usually nicer way to achieve what you want.
Fortunately, calling local-eval isn't strictly necessary, as long as
the exciting and powerful `lexicals' macro is allowed. Then, the
`function' macro can be defined easily as:
(define-syntax function
(lambda (x)
(syntax-case x ()
((function args body ...)
#'(let ((procedure (lambda args body ...))
(get-lexicals (lambda()(lexicals function))))
(set-procedure-property! procedure 'source '(function args body ...))
(set-procedure-property! procedure 'get-lexicals get-lexicals)
procedure)))))
(define (procedure-lexicals proc)
((procedure-property proc 'get-lexicals)))
I don't fully understand why it works, as syntax-case is still a
mystery to me, but I wrote it and it works perfectly, not to mention
that the expanded code is much cleaner now, without the-environment.
