// C# compiler generates IL with a "leave" instruction outside of a try-catch scenario..
// we need to treat it as a "br" instruction (NOT LEAVING a protected area).
private static T FirstOrDefault <T>(T[] source, pred <T> predicate)
{
foreach (var s in source)
{
if (predicate(s))
{
return(s);
}
}
return(default(T));
}
public Stream <T> takeWhile(pred <T> pred)
{
state <T, Stream <T> > guard = s =>
{
if (s.IsEmpty)
{
return(null);
}
else
{
if (!pred(s.Head))
{
return(null);
}
else
{
return(new Tuple <T, Stream <T> >(s.Head, s.Tail));
}
}
};
return(unfold(this, guard));
}