/// <summary>
/// Returns the possible ways that a query term can unify with a program term
/// </summary>
public static IBindings Unify(this ILiteral query, ILiteral program, IBindings bindings = null)
{
var simpleUnifier = new SimpleUnifier();
var freeVariables = new HashSet<ILiteral>();
// Run the unifier
var queryFreeVars = simpleUnifier.QueryUnifier.Compile(query, bindings);
if (queryFreeVars == null) return null;
simpleUnifier.PrepareToRunProgram();
var programFreeVars = simpleUnifier.ProgramUnifier.Compile(program, bindings);
if (programFreeVars == null) return null;
freeVariables.UnionWith(queryFreeVars);
// Retrieve the unified value for the program
var result = simpleUnifier.UnifiedValue(query.UnificationKey ?? query);
// If the result was valid, return as the one value from this function
if (result != null)
{
var variableBindings = freeVariables.ToDictionary(variable => variable,
variable => simpleUnifier.UnifiedValue(variable));
return new BasicBinding(result, variableBindings);
}
else
{
return null;
}
}
