public Constrains GetCopy()
{
var result = new Constrains(Descedant, Ancestor)
{
IsComparable = this.IsComparable,
Prefered = this.Prefered
};
return(result);
}
public IState MergeOrNull(Constrains constrains)
{
var result = new Constrains(Descedant, Ancestor)
{
IsComparable = this.IsComparable || constrains.IsComparable
};
result.AddDescedant(constrains.Descedant);
if (!result.TryAddAncestor(constrains.Ancestor))
{
return(null);
}
if (result.HasAncestor && result.HasDescendant)
{
var anc = result.Ancestor;
var des = result.Descedant;
if (anc.Equals(des))
{
if (result.IsComparable && !anc.IsComparable)
{
return(null);
}
return(anc);
}
if (!des.CanBeImplicitlyConvertedTo(anc))
{
return(null);
}
}
if (Prefered == null)
{
result.Prefered = constrains.Prefered;
}
else if (constrains.Prefered == null)
{
result.Prefered = Prefered;
}
else if (constrains.Prefered.Equals(Prefered))
{
result.Prefered = Prefered;
}
else if (result.Fits(Prefered) && !result.Fits(constrains.Prefered))
{
result.Prefered = Prefered;
}
else
{
result.Prefered = constrains.Prefered;
}
return(result);
}