[gambit-list] macro tricks
lowly coder
lowlycoder at huoyanjinjing.com
Fri Aug 14 02:19:36 EDT 2009
so if I use (env-ref (the-env) 'foo#x) , it works
perhaps this is due to me not understanding how ##namespace works
Marc -- can you explain a bit more about how ##namespace is
implemented? I seem to often misunderstand it. My current
understanding is that ##namespae is handled all at read time, where if
I have
(##namespace ("foo#"))
then in the rest of the file, if gambit reads any unquoted symbol
'asdf', it replaces it with foo#asdf
On Thu, Aug 13, 2009 at 11:01 PM, lowly
coder<lowlycoder at huoyanjinjing.com> wrote:
> This doesn't seem to work with namespaces
>
> For example:
>
> (namespace ("foo#"))
> (##include "~~lib/gambit#.scm")
>
>
> (##define-macro (macro-code-cte c)
> `(##vector-ref ,c 2))
>
> (##define-macro (macro-rte-up rte)
> `(##vector-ref ,rte 0))
>
>
>
> (define (the-env)
> (##continuation-capture
> (lambda (cont)
> (if (##interp-continuation? cont)
> (let (($code (##interp-continuation-code cont))
> (rte (##interp-continuation-rte cont)))
> (cons (macro-code-cte $code) rte))
> (error "the-env must be called from interpreted code")))))
>
> (define (env-ref env var)
> (let loop1 ((c (car env))
> (r (cdr env)))
> (cond ((##cte-top? c)
> (##global-var-ref (##make-global-var var)))
> ((##cte-frame? c)
> (let loop2 ((vars (##cte-frame-vars c))
> (i 1))
> (if (pair? vars)
> (if (eq? var (##car vars))
> (vector-ref r i)
> (loop2 (cdr vars)
> (+ i 1)))
> (loop1 (##cte-parent-cte c)
> (macro-rte-up r)))))
> (else
> (loop1 (##cte-parent-cte c)
> r)))))
>
>
> (define x 20)
>
> (pp (env-ref (the-env) 'x))
>
>
> --> gives me #!unbound
>
> yet if I uncomment the first two lines, I get 20
>
>
> Thanks!
>
> On Thu, Aug 13, 2009 at 1:45 PM, lowly
> coder<lowlycoder at huoyanjinjing.com> wrote:
>> Works perfectly. Thanks!
>>
>> On Thu, Aug 13, 2009 at 5:56 AM, Marc Feeley<feeley at iro.umontreal.ca> wrote:
>>>
>>> On 13-Aug-09, at 7:22 AM, lowly coder wrote:
>>>
>>>> it looks like the stuff in lib/_eval.scm , especially with ##eval and
>>>> the ##*cte* stuff seems like it might work; but I can't quite get it;
>>>> anyone have experience?
>>>>
>>>> On Thu, Aug 13, 2009 at 4:09 AM, lowly
>>>> coder<lowlycoder at huoyanjinjing.com> wrote:
>>>>>
>>>>> (define-macro (foo)
>>>>> (define x 20)
>>>>> (define (magic-func var-name)
>>>>> ...)
>>>>>
>>>>> (pp (magic-func 'x)))
>>>>>
>>>>> (foo)
>>>>>
>>>>>
>>>>> Is there anyway I can define magic-func so that 20 is outputted?
>>>>
>>>
>>>
>>> With the code attached below, do:
>>>
>>> (define (magic-func var-name)
>>> (env-ref (the-env) var-name))
>>>
>>> Marc
>>>
>>>
>>>
>>> (include "~~lib/_gambit#.scm")
>>>
>>> (define (the-env) ;; get the environment at the call site
>>> (##continuation-capture
>>> (lambda (cont)
>>> (if (##interp-continuation? cont)
>>> (let (($code (##interp-continuation-code cont))
>>> (rte (##interp-continuation-rte cont)))
>>> (cons (macro-code-cte $code) rte))
>>> (error "the-env must be called from interpreted code")))))
>>>
>>> (define (env-ref env var) ;; fetch variable from an environment
>>> (let loop1 ((c (car env))
>>> (r (cdr env)))
>>> (cond ((##cte-top? c)
>>> (##global-var-ref (##make-global-var var)))
>>> ((##cte-frame? c)
>>> (let loop2 ((vars (##cte-frame-vars c))
>>> (i 1))
>>> (if (pair? vars)
>>> (if (eq? var (##car vars))
>>> (vector-ref r i)
>>> (loop2 (cdr vars)
>>> (+ i 1)))
>>> (loop1 (##cte-parent-cte c)
>>> (macro-rte-up r)))))
>>> (else
>>> (loop1 (##cte-parent-cte c)
>>> r)))))
>>>
>>> (define (env-set! env var val) ;; modify variable in an environment
>>> (let loop1 ((c (car env))
>>> (r (cdr env)))
>>> (cond ((##cte-top? c)
>>> (##global-var-set! (##make-global-var var) val))
>>> ((##cte-frame? c)
>>> (let loop2 ((vars (##cte-frame-vars c))
>>> (i 1))
>>> (if (pair? vars)
>>> (if (eq? var (##car vars))
>>> (vector-set! r i val)
>>> (loop2 (cdr vars)
>>> (+ i 1)))
>>> (loop1 (##cte-parent-cte c)
>>> (macro-rte-up r)))))
>>> (else
>>> (loop1 (##cte-parent-cte c)
>>> r)))))
>>>
>>> ;; test:
>>>
>>> (define (f var)
>>> (let ((x 11))
>>>
>>> (define (g y) (* y y))
>>>
>>> (pp (env-ref (the-env) 'g))
>>>
>>> (pp (env-ref (the-env) var))
>>> (env-set! (the-env) var 22)
>>> (pp (env-ref (the-env) var))
>>>
>>> (pp (g x))))
>>>
>>> (f 'x)
>>>
>>>
>>
>
More information about the Gambit-list
mailing list