/* 

  Conversion between kg <-> lb in Picat.


  This Picat model was created by Hakan Kjellerstrand, hakank@gmail.com
  See also my Picat page: http://www.hakank.org/picat/

*/


import mip.


main => go.

main([KgS,LbS]) =>
  println("Syntax: kg_lb.pl Kg Lb (0 mean indicates weight)"),
  KgFloat = KgS.to_float(),
  LbFloat = LbS.to_float(),
  if KgFloat > 0.0 then Kg = KgFloat end,
  if LbFloat > 0.0 then Lb = LbFloat end,
  convert_mip(Kg,Lb),
  printf("%3.2fkg <-> %3.2flb\n", Kg,Lb),
  nl.

go =>
  
  % Kg = 100.0,
  Lb = 100,
  convert_mip(Kg,Lb),
  printf("%3.2fkg <-> %3.2flb\n", Kg,Lb),
  nl.

to_lb(Kg) = 2.20462262*Kg. 
to_kg(Lb) = Lb/2.20462262. 

convert_mip(Kg,Lb) =>
  if (nonvar(Kg), nonvar(Lb)) ; (var(Kg), var(Lb)) then
     println("Some - but not both - of Kg and Lb should be > 0"),
     halt
  end,
  if var(Kg) then
    Kg :: 0.0..10000.0
  else
    Lb :: 0.0..10000.0
  end,
  Lb #= 2.20462262*Kg,
  solve([Lb,Kg]).


convert(Kg,Lb) =>
  if Kg =:= 0.0, Lb =:= 0.0 then
     println("Some of Kg and Lb should be > 0"),
     halt
  end,
  if Kg > 0.0, Lb > 0.0 then
     println("Both of Kg and Lb cannot be > 0"),
     halt
  end,

  if Kg =:= 0.0 then
    printf("%0.2flb -> %0.2fkg\n", Lb,to_kg(Lb))
  else 
    printf("%0.2fkg -> %0.2flb\n", Kg,to_lb(Kg))
  end,
  nl.