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Re: expression
From: |
Michael Lucy |
Subject: |
Re: expression |
Date: |
Wed, 23 Jun 2010 18:23:45 -0500 |
Doesn't look like it ignores it:
scheme@(guile-user)> ,c (begin (set! x 1))
Disassembly of #<objcode bdc6e48>:
0 (assert-nargs-ee/locals 0)
2 (make-int8:1) ;; 1
3 (load-symbol "x") ;; x
8 (link-now)
9 (variable-set)
10 (void)
11 (return)
scheme@(guile-user)> ,c (begin (set! x 1) *unspecified*)
Disassembly of #<objcode 9a05d08>:
0 (assert-nargs-ee/locals 0)
2 (make-int8:1) ;; 1
3 (load-symbol "x") ;; x
8 (link-now)
9 (variable-set)
10 (load-symbol "*unspecified*") ;; *unspecified*
27 (link-now)
28 (variable-ref)
29 (return)
scheme@(guile-user)>
If it's idiomatic I'll do that till I find something else though. Thanks!
On Wed, Jun 23, 2010 at 6:14 PM, No Itisnt <address@hidden> wrote:
> On Wed, Jun 23, 2010 at 4:09 PM, Michael Lucy <address@hidden> wrote:
>> Hey,
>>
>> Is there any scheme expression that will just get ignored when the
>> scheme code is compiled?
>>
>> I'm generating some code with a function like:
>>
>> (define (gen-update-ab updatea updateb)
>> `(begin
>> ,(if updatea `(set! a (+ a 1)) `(donothing))
>> ,(if updateb `(set! b (+ b 1)) `(donothing))))
>>
>> And ideally I could replace the donothing function with something that
>> will get discarded during compilation.
>
> I'm not sure if Guile will discard the result, but I think
> *unspecified* is the idiomatic value for those sorts of situations.
>