------------------------------------------------------------------------
--
-- * used only in (lparser) luaY:subexpr()
------------------------------------------------------------------------

function luaK:prefix(fs, op, e)
  local e2 = {}  -- expdesc
  e2.t, e2.f = self.NO_JUMP, self.NO_JUMP
  e2.k = "VKNUM"
  e2.nval = 0
  if op == "OPR_MINUS" then
    if not self:isnumeral(e) then
      self:exp2anyreg(fs, e)  -- cannot operate on non-numeric constants
    end
    self:codearith(fs, "OP_UNM", e, e2)
  elseif op == "OPR_NOT" then
    self:codenot(fs, e)
  elseif op == "OPR_LEN" then
    self:exp2anyreg(fs, e)  -- cannot operate on constants
    self:codearith(fs, "OP_LEN", e, e2)
  else
    assert(0)
  end
end
