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From: Andy Wingo <wingo@pobox.com>
To: Michael Lucy <MichaelGLucy@Gmail.com>
Cc: guile-devel@gnu.org, No Itisnt <theseaisinhere@gmail.com>
Subject: Re: expression
Date: Thu, 24 Jun 2010 15:01:44 +0200	[thread overview]
Message-ID: <m3pqzg7fev.fsf@pobox.com> (raw)
In-Reply-To: <AANLkTimZDg1mZyS8wj7nVw6uGSaAP1p-zHzzeKOAolsU@mail.gmail.com> (Michael Lucy's message of "Wed, 23 Jun 2010 18:23:45 -0500")

Hi Michael,

On Thu 24 Jun 2010 01:23, Michael Lucy <MichaelGLucy@Gmail.com> writes:

> 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)

In current Guile, *unspecified* is actually a macro, allowing the
compiler to do its job better:

scheme@(guile-user)> ,c (begin (set! x 1) *unspecified*)
<stdin>:1:10: warning: possibly unbound variable `x'
Disassembly of #<objcode 94a1908>:

   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)                        

Andy
-- 
http://wingolog.org/



  reply	other threads:[~2010-06-24 13:01 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-06-23 21:09 expression Michael Lucy
2010-06-23 23:14 ` expression No Itisnt
2010-06-23 23:23   ` expression Michael Lucy
2010-06-24 13:01     ` Andy Wingo [this message]
2010-06-24  6:55 ` expression Ken Raeburn
2010-06-24  7:27   ` expression Thien-Thi Nguyen
2010-06-24  7:52   ` expression Michael Lucy
2010-06-24 13:05     ` expression Andy Wingo
2010-06-24 13:03   ` expression Andy Wingo
2010-06-24 14:40     ` expression Ken Raeburn

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