/* 

  Conversion Celsius <-> Fahrenheit in Picat.

  This is a standard example showing the reversibility of 
  Constraint Programming (etc), here a single predicate 
  converts from Celsius to Fahrenheit or from Fahrenheit to Celsius.

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

*/


% import util.
import mip.


main => go.

go => 
  C1 = 0.0,
  convert(C1,F1),
  println([C1,F1]),


  F2 = 100.0,
  convert(C2,F2),
  println([C2,F2]),

  nl.


go2 => 
  foreach(C in -10..10)
     convert(C,F),
     println([C,F]),    
     nl
  end,
  nl.

% find integer values of C and F
go3 => 
  C :: -100..100,
  F :: -100..100,

  convert(C,F),
  println([C,F]),

  % fail,

  nl.

convert(C,F) =>
  C * 9.0 #= (F - 32.0) * 5.0,
  solve([C,F]).