dom method

This method translates a dominance literal dom(X R Y) into the corresponding problem-specific constraint (as described in Section 4.3.2). Remember that since is the inverse of , we only represent one of them: we represent when are encoded by I,J and I>J.

<Dominance: Solver class, dom method>=

meth dom(X R Y)
   {self var2node(X _)}
   {self var2node(Y _)}
   I = @var2int.X
   J = @var2int.Y
in 
   if I==J then 1::{Encode R}
   elseif I>J then 
      @choices.(I*1000+J)::{Encode R}
   else 
      @choices.(J*1000+I)::{Encode {Inverse R}}
   end 
end

Here is how to inverse and encode the symbolic representation of a dominance specification.

<Dominance: utilities>= <<

fun {Encode R}
   case R
   of eq    then 1
   [] above then 2
   [] below then 3
   [] side  then 4
   [] _|_   then {Map R Encode}
   end 
end 
fun {Inverse R}
   case R
   of eq    then eq
   [] above then below
   [] below then above
   [] side  then side
   [] _|_   then {Map R Inverse}
   end 
end