Re: Definion of 'for' statement in the manual

[Dirk Laurie <dirk.laurie@...>]

2015-09-26 20:32 GMT+02:00 Roberto Ierusalimschy <roberto@inf.puc-rio.br>:
>> >> Why does Lua 5.3's reference does "var = var - step" instead of simply
>> >> moving the "var = var + step" after "block" (as in Lua 5.2)?
>> >
>> > This is how it is implemented, and both ways can give different results.
>> > (That it is why we do not like to specify things with code, it gives too
>> > much details that should be left open.)
>>
>> How could both ways give different results?
>
> Floating point operations. See the next example:
>
>   > for i = -2^53, -2^53 + 2 do print(string.format("%.0f", i)) end
>   -9007199254740991
>   -9007199254740990
>
> (Note that the given initial value, -2^53, is -9007199254740992.)

On my machine Lua 5.1, 5.2, 5.3 all give that, so where is the
difference?