Originally Posted by zgrssd
I asume AreId64sEqual does som additional checks. The logic most be more complex then A ~= B, if they write an extra function for it.
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I don't think it's more complex, but is required due the way Lua stores numbers
http://lua-users.org/wiki/NumbersTutorial
Since numbers in Lua are double-precision floating-point (1 bit sign, 11 bits exponent, 52 bits mantisa), integers are only precise below 2^53. Try comparing (2^53 == 2^53+1) in Lua console, the answer is surprisingly "true". That's because binary representation of 2^53+1 is "1..(52x0)..1", but there is not enough room to store 53 bits in mantisa, and so it gets rounded to 2^53.
NB for the curious: 2^53+1 or "1..(52x0)..1" is 54 bits long, but I wrote there's no room for 53 bits. It's not a typo, the initial "1" bit is implied, not stored anywhere. It's part of the standard https://en.wikipedia.org/wiki/IEEE_floating_point
They probably return the 64-bit integer ID in Lua number, but that's not guaranteed to be a valid floating-point number (some bit combinations are simply invalid, and floating-point operations on such values, including comparison, might yield weird results). Those comparison functions are probably circumventing floating-point comparison, and do integer comparison in C instead. But it's just my guess
