public IEnumerable <Span> Flatten()
{
// Create an enumerable that flattens the tree for use by syntax highlighters, etc.
foreach (SyntaxTreeNode element in Children)
{
Span span = element as Span;
if (span != null)
{
yield return(span);
}
else
{
Block block = element as Block;
foreach (Span childSpan in block.Flatten())
{
yield return(childSpan);
}
}
}
}
