You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
85 lines
1.9 KiB
85 lines
1.9 KiB
#ifndef INC_TokenStreamHiddenTokenFilter_hpp__
|
|
#define INC_TokenStreamHiddenTokenFilter_hpp__
|
|
|
|
#include "antlr/config.h"
|
|
#include "antlr/TokenStreamBasicFilter.h"
|
|
|
|
ANTLR_BEGIN_NAMESPACE(antlr)
|
|
|
|
/**This object filters a token stream coming from a lexer
|
|
* or another TokenStream so that only certain token channels
|
|
* get transmitted to the parser.
|
|
*
|
|
* Any of the channels can be filtered off as "hidden" channels whose
|
|
* tokens can be accessed from the parser.
|
|
*/
|
|
class TokenStreamHiddenTokenFilter : public TokenStreamBasicFilter {
|
|
// protected BitSet discardMask;
|
|
protected:
|
|
BitSet hideMask;
|
|
|
|
private:
|
|
RefToken nextMonitoredToken;
|
|
|
|
protected:
|
|
/** track tail of hidden list emanating from previous
|
|
* monitored token
|
|
*/
|
|
RefToken lastHiddenToken;
|
|
|
|
RefToken firstHidden; // = null;
|
|
|
|
public:
|
|
TokenStreamHiddenTokenFilter(TokenStream& input);
|
|
|
|
protected:
|
|
void consume();
|
|
|
|
private:
|
|
void consumeFirst();
|
|
|
|
public:
|
|
BitSet getDiscardMask() const;
|
|
|
|
/** Return a ptr to the hidden token appearing immediately after
|
|
* token t in the input stream.
|
|
*/
|
|
RefToken getHiddenAfter(RefToken t);
|
|
|
|
/** Return a ptr to the hidden token appearing immediately before
|
|
* token t in the input stream.
|
|
*/
|
|
RefToken getHiddenBefore(RefToken t);
|
|
|
|
BitSet getHideMask() const;
|
|
|
|
/** Return the first hidden token if one appears
|
|
* before any monitored token.
|
|
*/
|
|
RefToken getInitialHiddenToken();
|
|
|
|
void hide(int m);
|
|
|
|
void hide(const BitSet& mask);
|
|
|
|
protected:
|
|
RefToken LA(int i);
|
|
|
|
public:
|
|
/** 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 nextToken();
|
|
};
|
|
|
|
ANTLR_END_NAMESPACE
|
|
|
|
#endif //INC_TokenStreamHiddenTokenFilter_hpp__
|