internal override bool SubtractImpl(FeatureValue other, VariableBindings varBindings, IDictionary <FeatureStruct, ISet <FeatureStruct> > visited)
{
SimpleFeatureValue otherSfv;
if (!Dereference(other, out otherSfv))
{
return(true);
}
if (!IsVariable && !otherSfv.IsVariable)
{
ExceptWith(false, otherSfv, false);
}
else if (IsVariable && !otherSfv.IsVariable)
{
SimpleFeatureValue binding;
if (varBindings.TryGetValue(VariableName, out binding))
{
UnionWith(false, binding, !Agree);
ExceptWith(false, otherSfv, false);
VariableName = null;
}
}
else if (!IsVariable && otherSfv.IsVariable)
{
SimpleFeatureValue binding;
if (varBindings.TryGetValue(otherSfv.VariableName, out binding))
{
ExceptWith(false, binding, !otherSfv.Agree);
}
}
else
{
SimpleFeatureValue binding;
if (varBindings.TryGetValue(VariableName, out binding))
{
UnionWith(false, binding, !Agree);
SimpleFeatureValue otherBinding;
if (varBindings.TryGetValue(otherSfv.VariableName, out otherBinding))
{
ExceptWith(false, otherSfv, false);
}
VariableName = null;
}
else if (!varBindings.ContainsVariable(otherSfv.VariableName))
{
return(VariableName != otherSfv.VariableName || Agree != otherSfv.Agree);
}
}
return(IsSatisfiable);
}
