Re: [boost] Interest for a perl6-like-junctions-class?

From: Jeff Flinn (TriumphSprint2000_at_[hidden])
Date: 2005-07-25 13:19:16

<FlSt_at_[hidden]> wrote in message news:42E51034.7040508_at_gmx.de...
> Hello Rob.
>
>>>[...]
>>>
>>I have a few questions about your design:
>>
>>   Why "super position" versus Perl's "junction?"  When
>>   describing the enumerators, you use the Perl terminology,
>>   apparently because it makes sense.  Frankly, I don't "get"
>>   "super position."
>>
> Before it was a built-in feature of Perl, something similar was
> available as a CPAN module called Quantum::SuperPosition. This naming
> comes from the quantum physics where elementary particles can have more
> than one state, called super position. But i think its more evident to
> call it "junction". (Furthermore "super position" sounds overblown ;-)

Perhaps part of the confusion is that "superposition" is a single word and 
not two. Merriam Webster defines superposition:

1 : to place or lay over or above whether in or not in contact : SUPERIMPOSE
2 : to lay (as a geometric figure) upon another so as to make all like parts 
coincide

That said, the functionality(in the 1st example) appears to me as a 
compile-time-set of values. Perhaps mpl already has much of the needed 
facilities to say(for the scalar case):

    if( compile_time_set<1,4,9>().count( dave ) ) ...

Reading the link describing junction even further, it appears that std::set 
provides some of the desired functionality. There have been at least a few 
posting here and on comp.lang.c++* discussing making set operations more 
complete. I've been finding myself addressing these issue often enough these 
days to look at implementing a more general solution.

So rather than creating new(as far as C++ is concerned) terminology, I'd 
find general expansion of set manipulating functionality more useful.

Thanks,

Jeff Flinn