/// <summary>
/// If <paramref name="tokenContainer"/> is a single token, then enumerates it.
/// If <paramref name="tokenContainer"/> is token collection, then enumerates all contained tokens.
/// If <paramref name="recurse"/> is true, then enumerates tree of collections.
/// </summary>
/// <param name="tokenContainer"></param>
/// <param name="recurse"></param>
/// <returns>enumerable of tokens</returns>
public static IEnumerable <IToken> ListTokens(this IOption tokenContainer, bool recurse = true)
{
// Is a token
if (tokenContainer is IToken token)
{
// Enumerable
if (tokenContainer is ITokenEnumerable enumr)
{
// Return enumerable as is
if (!recurse)
{
return(enumr);
}
// Put into queue
StructList4 <IToken> queue = new StructList4 <IToken>();
foreach (IToken t in enumr)
{
queue.Add(t);
}
StructListSorter <StructList4 <IToken>, IToken> .Reverse(ref queue);
StructList4 <IToken> result = new StructList4 <IToken>();
while (queue.Count > 0)
{
int ix = queue.Count - 1;
IToken t = queue[ix];
queue.RemoveAt(ix);
if (t is ITokenEnumerable enumr_)
{
foreach (IToken tt in enumr_)
{
queue.Add(tt);
}
}
else
{
result.Add(t);
}
}
return(result.ToArray());
}
// Single token
else
{
return new IToken[] { token }
};
}
else
{
// No tokens
return(no_tokens);
}
}