At 07:37 2005-06-02, christopher diggins wrote:
----- Original Message ----- From: "Victor A. Wagner Jr." <vawjr@rudbek.com>
[deleted]
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 allowing:
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"; ??
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-Christopher Diggins
Victor A. Wagner Jr. http://rudbek.com The five most dangerous words in the English language: "There oughta be a law"