private void consumeFirst()
{
consume(); // get first token of input stream
// Handle situation where hidden or discarded tokens
// appear first in input stream
IHiddenStreamToken p = null;
// while hidden or discarded scarf tokens
while (hideMask.member(LA(1).Type) || discardMask.member(LA(1).Type))
{
if (hideMask.member(LA(1).Type))
{
if (p == null)
{
p = LA(1);
}
else
{
p.setHiddenAfter(LA(1));
LA(1).setHiddenBefore(p); // double-link
p = LA(1);
}
lastHiddenToken = p;
if (firstHidden == null)
{
firstHidden = p; // record hidden token if first
}
}
consume();
}
}
/*Return the next monitored token.
* Test the token following the monitored token.
* If following is another monitored token, save it
* for the next invocation of nextToken (like a single
* lookahead token) and return it then.
* If following is unmonitored, nondiscarded (hidden)
* channel token, add it to the monitored token.
*
* Note: EOF must be a monitored Token.
*/
override public IToken nextToken()
{
// handle an initial condition; don't want to get lookahead
// token of this splitter until first call to nextToken
if (LA(1) == null)
{
consumeFirst();
}
// we always consume hidden tokens after monitored, thus,
// upon entry LA(1) is a monitored token.
IHiddenStreamToken monitored = LA(1);
// point to hidden tokens found during last invocation
monitored.setHiddenBefore(lastHiddenToken);
lastHiddenToken = null;
// Look for hidden tokens, hook them into list emanating
// from the monitored tokens.
consume();
IHiddenStreamToken p = monitored;
// while hidden or discarded scarf tokens
while (hideMask.member(LA(1).Type) || discardMask.member(LA(1).Type))
{
if (hideMask.member(LA(1).Type))
{
// attach the hidden token to the monitored in a chain
// link forwards
p.setHiddenAfter(LA(1));
// link backwards
if (p != monitored)
{
//hidden cannot point to monitored tokens
LA(1).setHiddenBefore(p);
}
p = (lastHiddenToken = LA(1));
}
consume();
}
return(monitored);
}