Hi, C:\>raku -e "say 1.8446744073709552e+19 == 18446744073709551615" True
I think I understand why raku deems this to be true. The LHS is 0x1p+64, which is identical to the double that the RHS rounds to. (AFAIK, it's the same with perl5 and C.) Of course, for all $x in the Int range of 18446744073709551615 - 1023 to 18446744073709551615, we find that "1.8446744073709552e+19 == $x" is True, because each of those $x Int values round to 0x1p+64. I understand all of that (I think). What I don't understand is the following: C:\>raku -e "say 1.8446744073709552e+19 == (18446744073709551615 - 1024)" True C:\>raku -e "say 1.8446744073709552e+19 == (18446744073709551615 - 1087)" True For those particular Int values (and all Int values in between) the RHS rounds to 0x1.fffffffffffffp+63, and the result should therefore be "False" ... but it is reported as "True". It's not until we subtract at least 1088 that the behaviour I'm expecting appears: C:\>raku -e "say 1.8446744073709552e+19 == (18446744073709551615 - 1088)" False Comparing the RHS Int values given in the last 2 one liners, I find they are (respectively): 0.1111111111111111111111111111111111111111111111111111101111000000E64 0.1111111111111111111111111111111111111111111111111111101110111111E64 It's not apparent to me how those 2 integer values can round to different doubles. Those 2 integer values can also be written as (respectively): 18446744073709550528 18446744073709550527 On Windows, I have: C:\>raku --version This is Rakudo version 2020.05.1 built on MoarVM version 2020.05 implementing Raku 6.d. On Ubuntu, I have: $ raku --version Welcome to Rakudo(tm) v2021.03. Implementing the Raku(tm) programming language v6.d. Built on MoarVM version 2021.03. It's the same behaviour on both systems. Is this a bug that I ought to report ? Cheers, Rob
