Re: NaN in Lua 5.3 Reference Manual

[Martin <eden_martin_fuhrspam@...>]

On 06/23/2017 10:04 AM, John Hind wrote:
> [...] What about positive and
> negative zero? Would these be distinguished table keys?

With positive and negative float zeros is funny thing: you can't (I
don't know how) distinguish negative float zero (-0.0) from positive
float zero (0.0). Usually we detect negative number by comparing it with
0, which is not applicable here.

But in tables both three zeros as key maps to integer zero:

  Lua 5.3.3  Copyright (C) 1994-2016 Lua.org, PUC-Rio
  > t = {[0] = '0', [0.0] = '0.0', [-0.0] = '-0.0'}
  > for k, v in pairs(t) do print(math.type(k), k, v) end
  integer	0	-0.0

-- Martin