✨ Add SequenceSet#cardinality method #563
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nevans
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Unlike `#count`, `#cardinality` handles `*` in a more conventional way, as its own distinct member.
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When `SequenceSet#max(n)` is called with `n > cardinality`, it _should_ return a duplicate of the whole set. But, `#max(n)` is implemented using `#slice(-n..)`, and (copying the behavior of `Array`), when a slicing starts from an out-of-range index, it returns `nil`. It was using `-[count, size].min` to keep the index from going out-of-range. Prior to #564, `#size` was the same as `#count`, so it would give incorrect results when the set contains an endless range. After #564, this gives incorrect results when the ordered list contains duplicates. This change should also give a small performance boost, because it bypasses the complexity of `#slice(range)` and just calls `#dup` (or returns `self` when the set is frozen). This issue was one of the motivations for #563 (and #564), but then I forgot about the bug, so it wasn't fixed in time for 0.6.0!
nevans
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When `SequenceSet#max(n)` is called with `n > cardinality`, it _should_ return a duplicate of the whole set. But, `#max(n)` is implemented using `#slice(-n..)`, and (copying the behavior of `Array`), when a slicing starts from an out-of-range index, it returns `nil`. It was using `-[count, size].min` to keep the index from going out-of-range. Prior to #564, `#size` was the same as `#count`, so it would give incorrect results when the set contains an endless range. After #564, this gives incorrect results when the ordered list contains duplicates. This change should also give a small performance boost, because it bypasses the complexity of `#slice(range)` and just calls `#dup` (or returns `self` when the set is frozen). This issue was one of the motivations for #563 (and #564), but then I forgot about the bug, so it wasn't fixed in time for 0.6.0!
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Unlike
#count,#cardinalityhandles*the way you would expect a set to handle it, as its own distinct member.