Re: [ANN] Lua 5.3.0 (work2) now available

[Roberto Ierusalimschy <roberto@...>]

> The argument becomes "Having an algorithm that needs changed
> for Lua, Perl and Free Pascal and those languages alone is the
> violation of the principle of least surprise". Not quite so convincing
> any more, especially as quite a few langages have not been
> tested yet by either party to the debate.

It should also be noted that to classify Python shifts as "arithmetic
shifts" is not very precise, because Python does not have fixed-width
integers. It seems more precise to say that Python is like C, with
logical shifts for unsigned integers and arithmetic shifts for signed
integers:

  x = 0xffffffffffffffff
  print(x, x >> 1)   --> (18446744073709551615L, 9223372036854775807L)

  x = -1
  print(x, x >> 1)   --> (-1, -1)

Very elegant BTW (but expensive). Knuth uses something similar in
his book of bit tricks (negative numbers have infinite 1's to the
left).

-- Roberto