public static State merge(State state1, State state2)
{
State ret = state1.Clone();
ret.Merge(state2);
return(ret);
}
public DataType VisitIf(IfStatement i)
{
DataType type1, type2;
State s1 = scope.Clone();
State s2 = scope.Clone();
// Ignore condition for now
i.Test.Accept(this);
if (i.Then != null)
{
type1 = i.Then.Accept(this);
}
else
{
type1 = DataType.Cont;
}
if (i.Else != null)
{
type2 = i.Else.Accept(this);
}
else
{
type2 = DataType.Cont;
}
bool cont1 = UnionType.Contains(type1, DataType.Cont);
bool cont2 = UnionType.Contains(type2, DataType.Cont);
// Decide which branch affects the downstream state
if (cont1 && cont2)
{
s1.Merge(s2);
scope.Overwrite(s1);
}
else if (cont1)
{
scope.Overwrite(s1);
}
else if (cont2)
{
scope.Overwrite(s2);
}
return(UnionType.Union(type1, type2));
}