public TypeEqualityInstance(Clause clause, int atomIndex)
{
Debug.Assert(atomIndex >= 0 && atomIndex < clause.literals.Count);
this.clause = clause;
this.atomIndex = atomIndex;
equality = clause.literals[atomIndex].f as EqualityFormula;
}
public CNF2State(EqualityFormula eq, bool p)
{
if (!eq.isTrue)
{
var nc = new Clause(eq, p);
pClauses[nc.ToString()] = nc;
}
}
public IFormula visit(EqualityFormula f)
{
if (f.t1.Equals(f.t2))
{
return(new True());
}
return(f);
}
public Clause(EqualityFormula f, bool p)
: this(
new PredicateApplication[0],
new PredicateApplication[0],
p ? new[] { f } : new EqualityFormula[0],
!p ? new[] { f } : new EqualityFormula[0]
)
{
}
//////////////////////////////////////////////////////////////////////////////////////////
private static bool tryUnify(EqualityFormula eq1, EqualityFormula eq2, Substitution s)
{
Debug.Assert(eq1.t1.type.isEquivalent(eq2.t1.type));
//record substitution as has to check both ways
s.push();
if (tryUnify(eq1.t1, eq2.t1, s) && tryUnify(eq1.t2, eq2.t2, s))
{
return(true);
}
s.pop();
return(tryUnify(eq1.t1, eq2.t2, s) && tryUnify(eq1.t2, eq2.t1, s));
}
public IFormula visit(EqualityFormula f)
{
return(f);
}
public IFormula visit(EqualityFormula f)
{
return(new Not(f));
}
internal static string polish(EqualityFormula f, IDictionary <string, string> vm)
{
return("(= " + polish(f.t1, vm) + " " + polish(f.t2, vm) + ")");
}