🚀 go-pugleaf

[Moderator's note: my apologies for letting this thread continue,
 since it has strayed from the topic of C++ standardization.  I
 approved this article since I think it would be unfair to deny the
 poster a right of reply in this case (perhaps I shouldn't have
 approved the article to which he is replying).  Anyway, please try to
 make our job as moderators easier by making sure that articles
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In message <312495AD.757A@ebc.ericsson.se> - Bjorn Fahller 
<ebcbear@ebc.ericsson.se> writes:
:>
:>David Byrden <100101.2547@compuserve.com> wrote:
:>> 
:>> >> I'd like to be able to call "DoIt" with any type of object and a
:>> >> pointer to any of that object's member functions that match the
:>> >> 'parmlist'
:>> 
:>>  In the C++ Report, February 1995, Richard Hickey suggested a library of
:>> universal callback functors which would encapsulate both an object
:>> reference and a pointer to a member function of that object.
:>> 
:>>  The caller, and the provider of the callback, would not have to share
:>> any type information other than the callback library itself.
:>
:>Unfortunately the implementation is all but clean, and depends
:>heavily on the compiler used. Internally, everything is
:>casted to void*. When I tried the implementation on Sun SparcWorks,
:>it failed, since pointer to member functions cannot be casted
:>to void* without severe loss of precision (they're twise
:>as long as void*.)
:>
:>The ideas are still usable, though. Those who are interested
:>can e-mail me for a simple example (not quite as slick as the
:>original, but not compiler dependant since it doesn't use
:>ugly casts.)
:>   _
:>/Bjorn.

Unfortunately you must not have understood the implementation.
I admit it is complex, difficult-to-read C++ code, yet it is
quite clean, and at no point are ptrs-to-members cast to void*.
If it doesn't work with your compiler I suggest your compiler
is broken.

I suggest you re-read the source quite carefully and make sure
you understand it before you criticize it. The callback library
is being used successfully by many experienced C++ developers.
No one has reported a language-level problem with it.

Anyone interested in the library source can decide for 
themselves. It is freely available at:
http://ourworld.compuserve.com/HomePages/RichHickey

Rich Hickey
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