/** 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.
*/
RefToken TokenStreamHiddenTokenFilter::nextToken()
{
// handle an initial condition; don't want to get lookahead
// token of this splitter until first call to nextToken
if ( !LA(1) ) {
consumeFirst();
}
// we always consume hidden tokens after monitored, thus,
// upon entry LA(1) is a monitored token.
RefToken monitored = LA(1);
// point to hidden tokens found during last invocation
static_cast<CommonHiddenStreamToken*>(monitored.get())->setHiddenBefore(lastHiddenToken);
lastHiddenToken = nullToken;
// Look for hidden tokens, hook them into list emanating
// from the monitored tokens.
consume();
RefToken p = monitored;
// while hidden or discarded scarf tokens
while ( hideMask.member(LA(1)->getType()) || discardMask.member(LA(1)->getType()) ) {
if ( hideMask.member(LA(1)->getType()) ) {
// attach the hidden token to the monitored in a chain
// link forwards
static_cast<CommonHiddenStreamToken*>(p.get())->setHiddenAfter(LA(1));
// link backwards
if (p != monitored) { //hidden cannot point to monitored tokens
static_cast<CommonHiddenStreamToken*>(LA(1).get())->setHiddenBefore(p);
}
p = lastHiddenToken = LA(1);
}
consume();
}
return monitored;
}
void TokenStreamHiddenTokenFilter::consumeFirst()
{
consume();
// Handle situation where hidden or discarded tokens
// appear first in input stream
RefToken p;
// while hidden or discarded scarf tokens
while ( hideMask.member(LA(1)->getType()) || discardMask.member(LA(1)->getType()) ) {
if ( hideMask.member(LA(1)->getType()) ) {
if ( !p ) {
p = LA(1);
}
else {
static_cast<CommonHiddenStreamToken*>(p.get())->setHiddenAfter(LA(1));
static_cast<CommonHiddenStreamToken*>(LA(1).get())->setHiddenBefore(p); // double-link
p = LA(1);
}
lastHiddenToken = p;
if (!firstHidden)
firstHidden = p; // record hidden token if first
}
consume();
}
}
/** Return a ptr to the hidden token appearing immediately before
* token t in the input stream.
*/
RefToken TokenStreamHiddenTokenFilter::getHiddenBefore(RefToken t)
{
return static_cast<CommonHiddenStreamToken*>(t.get())->getHiddenBefore();
}
void CommonASTWithHiddenTokens::initialize(RefToken t)
{
CommonAST::initialize(t);
hiddenBefore = static_cast<CommonHiddenStreamToken*>(t.get())->getHiddenBefore();
hiddenAfter = static_cast<CommonHiddenStreamToken*>(t.get())->getHiddenAfter();
}
