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From: Victor A. Wagner Jr. (vawjr_at_[hidden])
Date: 2005-06-02 10:55:50

At 07:37 2005-06-02, christopher diggins wrote:
>----- Original Message ----- From: "Victor A. Wagner Jr." <vawjr_at_[hidden]>


>>I argued (unsuccessfully) that when the boost::dynamic_bitset<> was
>>proposed that the _least_ we could do would be to fix the
>>mis-characterization of operators <= and >= with regards to sets (for
>>those who haven't studied sets, {b,c,d} <= {a,b,c,d} but that's not
>>how it will evaluate with either std::set or boost::dynamic_bitset).
>>Absent that oddity, I suspect that you could rather easily overload some
>>global operators to handle what you want using any of std::set,
>>std::bitset, or boost::dynamic_bitset (the backwardness of the comparison
>>operators would still bother me, though). Hmmmm, maybe I should look
>>more closely at the "unordered collections" (hash_set) proposal further
>>and see if that correctly manages the set concept.
>It might be very interesting to also overload comma to return sets, thus
>namespace true_sets
> assert((1, 2, 3) + (4, 5) < (1,2,3,4,5,6)}

iirc, Pascal only allowed <= (subset). I altered our compiler/library to
allow a < b to mean a <= b and a <> b (it seemed reasonable at the time
(still does)).
a <= b was defined as (!(a - b) = []) (for non Pascalers, []
was the empty set constant)

> assert((1, 2) == (2, 1)}
> assert(range(1, 3) == (2, 1, 3)}

I'm not sure how you're going to get the compiler to recognize (1, 2, 3) as
being the type (this_new_set), isn't that going to suffer from the same
problem that we have now with things like std::string abcdef = "abc" +
"def"; ??

>-Christopher Diggins

Victor A. Wagner Jr.
The five most dangerous words in the English language:
               "There oughta be a law"

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