Re: Definion of 'for' statement in the manual

[Roberto Ierusalimschy <roberto@...>]

> >> 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.)

-- Roberto