Protocols

[stepancheg]

Add "define" function signatures to core.operators.

I think this makes code easier to read and to maintain.

As part of this refactoring other parts of standard library were tweaked:

• twohash implementation was tweaked: size type changed from Int to SizeT
• twohash Table record made Sequence to overload begin function
• PushbackIterator push function renamed to pushback, because PushbackIterator is not Sequence

[jckarter]

Looks good, but does it work? Sequence? is defined in terms of iterator, and iterator for coordinate sequences in terms of begin and end, so having Sequence? in the signatures of these functions seems like it could cause a circularity.

[stepancheg]

I ran all tests, and tests pass. So if there is circularity, it is not revealed by Clay tests.

You must be talking about CoordinateRange. Iterator for CoordinateRange uses 'begin' and 'end' fields, and does not call 'begin' or end 'functions'.

I could also drop Sequence? condition from guards, and restrict only parameter count.

[jckarter]

OK, if the tests pass, it should be fine. Thanks.