--******************************************************************************
--*                                                                            *
--*  File:        Lua_04_Lib.lua                        Revision:  1.0         *
--*                                                                            *
--*  Purpose:     provides functions from "Lua_04" for other scripts           *
--*                                                                            *
--*  Creation:    07.03.2002                   Last Modification:  07.03.2002  *
--*                                                                            *
--*  Platform:    IBM-compatible PC running Windows 98SE                       *
--*                                                                            *
--*  Environment: Lua 4.0, TkLua 4.0                                           *
--*                                                                            *
--*  Author:      Andreas Rozek           Phone:  ++49 (711) 6770682           *
--*               Kirschblütenweg 15      Fax:    -                            *
--*             D-70569 Stuttgart         EMail:  Andreas.Rozek@T-Online.De    *
--*               Germany                                                      *
--*                                                                            *
--*  URL:         http://www.Andreas-Rozek.de/                                 *
--*                                                                            *
--*  Copyright:   the software is published under the "GNU Lesser General Pub- *
--*               lic  License" (see "http://www.fsf.org/copyleft/lesser.html" *
--*               for additional information)                                  *
--*                                                                            *
--*  Comments:    (none)                                                       *
--*                                                                            *
--******************************************************************************

  dofile("Lua_03_Lib.lua");

--**** map numeric operators on synonymous object methods ****

  local add_Mapper = function (Op1, Op2)
    if     (tag(Op1) == tag(Object)) then
      return Op1:__add__(Op2);            -- naming convention similar to Python
    elseif (tag(Op2) == tag(Object)) then
      return Op2:__radd__(Op1);           -- naming convention similar to Python
    else
      error(
        "error: unable to add non-numeric values (argument types are \""..
        type(Op1).."\" and \""..type(Op2).."\")"
      );
    end;
  end;
  settagmethod(tag(Object),"add",add_Mapper);

  local sub_Mapper = function (Op1, Op2)
    if     (tag(Op1) == tag(Object)) then
      return Op1:__sub__(Op2);            -- naming convention similar to Python
    elseif (tag(Op2) == tag(Object)) then
      return Op2:__rsub__(Op1);           -- naming convention similar to Python
    else
      error(
        "error: unable to subtract non-numeric values (argument types are \""..
        type(Op1).."\" and \""..type(Op2).."\")"
      );
    end;
  end;
  settagmethod(tag(Object),"sub",sub_Mapper);

  local mul_Mapper = function (Op1, Op2)
    if     (tag(Op1) == tag(Object)) then
      return Op1:__mul__(Op2);            -- naming convention similar to Python
    elseif (tag(Op2) == tag(Object)) then
      return Op2:__rmul__(Op1);           -- naming convention similar to Python
    else
      error(
        "error: unable to multiply non-numeric values (argument types are \""..
        type(Op1).."\" and \""..type(Op2).."\")"
      );
    end;
  end;
  settagmethod(tag(Object),"mul",mul_Mapper);

  local div_Mapper = function (Op1, Op2)
    if     (tag(Op1) == tag(Object)) then
      return Op1:__div__(Op2);            -- naming convention similar to Python
    elseif (tag(Op2) == tag(Object)) then
      return Op2:__rdiv__(Op1);           -- naming convention similar to Python
    else
      error(
        "error: unable to divide non-numeric values (argument types are \""..
        type(Op1).."\" and \""..type(Op2).."\")"
      );
    end;
  end;
  settagmethod(tag(Object),"div",div_Mapper);

  local pow_Mapper = function (Op1, Op2)
    if     (tag(Op1) == tag(Object)) then
      return Op1:__pow__(Op2);            -- naming convention similar to Python
    elseif (tag(Op2) == tag(Object)) then
      return Op2:__rpow__(Op1);           -- naming convention similar to Python
    else
      error(
        "error: unable to exponentiate non-numeric values (argument types are \""..
        type(Op1).."\" and \""..type(Op2).."\")"
      );
    end;
  end;
  settagmethod(tag(Object),"pow",pow_Mapper);

  local unm_Mapper = function (Op)
    if (tag(Op) == tag(Object)) then
      return Op:__neg__();                -- naming convention similar to Python
    else
      error(
        "error: unable to negate non-numeric values (argument type is \""..
        type(Op).."\")"
      );
    end;
  end;
  settagmethod(tag(Object),"unm",unm_Mapper);

  local lt_Mapper = function (Op1, Op2)
    if     (tag(Op1) == tag(Object)) then
      return Op1:__lt__(Op2);             -- naming convention similar to Python
    elseif (tag(Op2) == tag(Object)) then
      return Op2:__rlt__(Op1);            -- naming convention similar to Python
    else
      error(
        "error: unable to compare non-numeric and non-string values "..
        "(argument types are \""..type(Op1).."\" and \""..type(Op2).."\")"
      );
    end;
  end;
  settagmethod(tag(Object),"lt",lt_Mapper);

--**** provide "empty" methods within "Object" ****

  function Object:__add__ (Operand)            -- responsible for self + Operand
    error("error: no implementation for \"+\" operator found");
  end;

  function Object:__radd__ (Operand)           -- responsible for Operand + self
    error("error: no implementation for \"+\" operator found");
  end;

  function Object:__sub__ (Operand)            -- responsible for self - Operand
    error("error: no implementation for \"-\" operator found");
  end;

  function Object:__rsub__ (Operand)           -- responsible for Operand - self
    error("error: no implementation for \"-\" operator found");
  end;

  function Object:__mul__ (Operand)            -- responsible for self * Operand
    error("error: no implementation for \"*\" operator found");
  end;

  function Object:__rmul__ (Operand)           -- responsible for Operand * self
    error("error: no implementation for \"*\" operator found");
  end;

  function Object:__div__ (Operand)            -- responsible for self / Operand
    error("error: no implementation for \"/\" operator found");
  end;

  function Object:__rdiv__ (Operand)           -- responsible for Operand / self
    error("error: no implementation for \"/\" operator found");
  end;

  function Object:__pow__ (Operand)            -- responsible for self ^ Operand
    error("error: no implementation for \"^\" operator found");
  end;

  function Object:__rpow__ (Operand)           -- responsible for Operand ^ self
    error("error: no implementation for \"^\" operator found");
  end;

  function Object:__neg__ ()                            -- responsible for -self
    error("error: no implementation for sign operator found");
  end;

  function Object:__lt__ (Operand)             -- responsible for self < Operand
    error("error: no implementation for \"<\" operator (or similar) found");
  end;

  function Object:__rlt__ (Operand)            -- responsible for Operand < self
    error("error: no implementation for \"<\" operator (or similar) found");
  end;