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/*
* [The "BSD license"]
* Copyright (c) 2012 Terence Parr
* Copyright (c) 2012 Sam Harwell
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.antlr.v4.runtime;
import org.antlr.v4.runtime.atn.ATN;
import org.antlr.v4.runtime.atn.ATNSimulator;
import org.antlr.v4.runtime.atn.ATNState;
import org.antlr.v4.runtime.atn.ParserATNSimulator;
import org.antlr.v4.runtime.atn.RuleTransition;
import org.antlr.v4.runtime.dfa.DFA;
import org.antlr.v4.runtime.misc.IntervalSet;
import org.antlr.v4.runtime.misc.Nullable;
import org.antlr.v4.runtime.tree.ErrorNode;
import org.antlr.v4.runtime.tree.ParseTreeListener;
import org.antlr.v4.runtime.tree.ParseTreeWalker;
import org.antlr.v4.runtime.tree.TerminalNode;
import java.util.ArrayList;
import java.util.List;
/** This is all the parsing support code essentially; most of it is error recovery stuff. */
public abstract class Parser extends Recognizer {
public class TraceListener implements ParseTreeListener {
@Override
public void enterEveryRule(ParserRuleContext ctx) {
System.out.println("enter " + getRuleNames()[ctx.getRuleIndex()] +
", LT(1)=" + _input.LT(1).getText());
}
@Override
public void visitTerminal(TerminalNode node) {
System.out.println("consume "+node.getSymbol()+" rule "+
getRuleNames()[_ctx.getRuleIndex()]+
" alt="+_ctx.altNum);
}
@Override
public void visitErrorNode(ErrorNode node) {
}
@Override
public void exitEveryRule(ParserRuleContext ctx) {
System.out.println("exit "+getRuleNames()[ctx.getRuleIndex()]+
", LT(1)="+_input.LT(1).getText());
}
}
public static class TrimToSizeListener implements ParseTreeListener {
public static final TrimToSizeListener INSTANCE = new TrimToSizeListener();
@Override
public void enterEveryRule(ParserRuleContext ctx) { }
@Override
public void visitTerminal(TerminalNode node) { }
@Override
public void visitErrorNode(ErrorNode node) { }
@Override
public void exitEveryRule(ParserRuleContext ctx) {
if (ctx.children instanceof ArrayList) {
((ArrayList)ctx.children).trimToSize();
}
}
}
protected ANTLRErrorStrategy _errHandler = new DefaultErrorStrategy();
protected TokenStream _input;
/** The RuleContext object for the currently executing rule. This
* must be non-null during parsing, but is initially null.
* When somebody calls the start rule, this gets set to the
* root context.
*/
protected ParserRuleContext _ctx;
protected boolean _buildParseTrees = true;
protected TraceListener _tracer;
/** If the listener is non-null, trigger enter and exit rule events
* *during* the parse. This is typically done only when not building
* parse trees for later visiting. We either trigger events during
* the parse or during tree walks later. Both could be done.
* Not intended for average user!!! Most people should use
* ParseTreeListener with ParseTreeWalker.
* @see ParseTreeWalker
*/
protected List _parseListeners;
/** Did the recognizer encounter a syntax error? Track how many. */
protected int _syntaxErrors = 0;
public Parser(TokenStream input) {
setInputStream(input);
}
/** reset the parser's state */
public void reset() {
if ( getInputStream()!=null ) getInputStream().seek(0);
_errHandler.endErrorCondition(this);
_ctx = null;
_syntaxErrors = 0;
_tracer = null;
ATNSimulator interpreter = getInterpreter();
if (interpreter != null) {
interpreter.reset();
}
}
/** Match current input symbol against ttype. Attempt
* single token insertion or deletion error recovery. If
* that fails, throw MismatchedTokenException.
*/
public Token match(int ttype) throws RecognitionException {
Token t = getCurrentToken();
if ( t.getType()==ttype ) {
_errHandler.endErrorCondition(this);
consume();
}
else {
t = _errHandler.recoverInline(this);
if ( _buildParseTrees && t.getTokenIndex()==-1 ) {
// we must have conjured up a new token during single token insertion
// if it's not the current symbol
_ctx.addErrorNode(t);
}
}
return t;
}
public Token matchWildcard() throws RecognitionException {
Token t = getCurrentToken();
if (t.getType() > 0) {
_errHandler.endErrorCondition(this);
consume();
}
else {
t = _errHandler.recoverInline(this);
if (_buildParseTrees && t.getTokenIndex() == -1) {
// we must have conjured up a new token during single token insertion
// if it's not the current symbol
_ctx.addErrorNode(t);
}
}
return t;
}
/** Track the RuleContext objects during the parse and hook them up
* using the children list so that it forms a parse tree.
* The RuleContext returned from the start rule represents the root
* of the parse tree.
*
* To built parse trees, all we have to do is put a hook in setState()
* and enterRule(). In setState(), we add tokens to the current context
* as children. By the time we get to enterRule(), we are already
* in an invoked rule so we add this context as a child of the parent
* (invoking) context. Simple and effective.
*
* Note that if we are not building parse trees, rule contexts
* only point upwards. When a rule exits, it returns the context
* but that gets garbage collected if nobody holds a reference.
* It points upwards but nobody points at it.
*
* When we build parse trees, we are adding all of these contexts to
* somebody's children list. Contexts are then not candidates
* for garbage collection.
*/
public void setBuildParseTree(boolean buildParseTrees) {
this._buildParseTrees = buildParseTrees;
}
public boolean getBuildParseTree() {
return _buildParseTrees;
}
/**
* Trim the internal lists of the parse tree during parsing to conserve memory.
* This property is set to {@code false} by default for a newly constructed parser.
*
* @param trimParseTrees {@code true} to trim the capacity of the {@link ParserRuleContext#children}
* list to its size after a rule is parsed.
*/
public void setTrimParseTree(boolean trimParseTrees) {
if (trimParseTrees) {
if (getTrimParseTree()) return;
addParseListener(TrimToSizeListener.INSTANCE);
}
else {
removeParseListener(TrimToSizeListener.INSTANCE);
}
}
/**
* @return {@code true} if the {@link ParserRuleContext#children} list is trimmed
* using the default {@link Parser.TrimToSizeListener} during the parse process.
*/
public boolean getTrimParseTree() {
if (_parseListeners == null) return false;
return _parseListeners.contains(TrimToSizeListener.INSTANCE);
}
// public void setTraceATNStates(boolean traceATNStates) {
// this.traceATNStates = traceATNStates;
// }
//
// public boolean getTraceATNStates() {
// return traceATNStates;
// }
public List getParseListeners() {
return _parseListeners;
}
/** Provide a listener that gets notified about token matches,
* and rule entry/exit events DURING the parse. It's a little bit
* weird for left recursive rule entry events but it's
* deterministic.
*
* THIS IS ONLY FOR ADVANCED USERS. Please give your
* ParseTreeListener to a ParseTreeWalker instead of giving it to
* the parser!!!!
*/
public void addParseListener(ParseTreeListener listener) {
if ( listener==null ) return;
if ( _parseListeners==null ) {
_parseListeners = new ArrayList();
}
this._parseListeners.add(listener);
}
public void removeParseListener(ParseTreeListener l) {
if ( l==null ) return;
if ( _parseListeners!=null ) {
_parseListeners.remove(l);
if (_parseListeners.isEmpty()) {
_parseListeners = null;
}
}
}
public void removeParseListeners() {
_parseListeners = null;
}
/** Notify any parse listeners (implemented as ParseTreeListener's)
* of an enter rule event. This is not involved with
* parse tree walking in any way; it's just reusing the
* ParseTreeListener interface. This is not for the average user.
*/
public void triggerEnterRuleEvent() {
for (ParseTreeListener l : _parseListeners) {
l.enterEveryRule(_ctx);
_ctx.enterRule(l);
}
}
/** Notify any parse listeners (implemented as ParseTreeListener's)
* of an exit rule event. This is not involved with
* parse tree walking in any way; it's just reusing the
* ParseTreeListener interface. This is not for the average user.
*/
public void triggerExitRuleEvent() {
// reverse order walk of listeners
for (int i = _parseListeners.size()-1; i >= 0; i--) {
ParseTreeListener l = _parseListeners.get(i);
_ctx.exitRule(l);
l.exitEveryRule(_ctx);
}
}
/** Get number of recognition errors (lexer, parser, tree parser). Each
* recognizer tracks its own number. So parser and lexer each have
* separate count. Does not count the spurious errors found between
* an error and next valid token match
*
* See also reportError()
*/
public int getNumberOfSyntaxErrors() {
return _syntaxErrors;
}
/** Tell our token source and error strategy about a new way to create tokens */
@Override
public void setTokenFactory(TokenFactory factory) {
_input.getTokenSource().setTokenFactory(factory);
_errHandler.setTokenFactory(factory);
}
public ANTLRErrorStrategy getErrorHandler() {
return _errHandler;
}
public void setErrorHandler(ANTLRErrorStrategy handler) {
this._errHandler = handler;
}
@Override
public TokenStream getInputStream() { return getTokenStream(); }
@Override
public final void setInputStream(IntStream input) {
setTokenStream((TokenStream)input);
}
public TokenStream getTokenStream() {
return _input;
}
/** Set the token stream and reset the parser */
public void setTokenStream(TokenStream input) {
this._input = null;
reset();
this._input = input;
}
/** Match needs to return the current input symbol, which gets put
* into the label for the associated token ref; e.g., x=ID.
*/
public Token getCurrentToken() {
return _input.LT(1);
}
public void notifyErrorListeners(String msg) {
notifyErrorListeners(getCurrentToken(), msg, null);
}
public void notifyErrorListeners(Token offendingToken, String msg,
@Nullable RecognitionException e)
{
int line = -1;
int charPositionInLine = -1;
line = offendingToken.getLine();
charPositionInLine = offendingToken.getCharPositionInLine();
ANTLRErrorListener listener = getErrorListenerDispatch();
listener.syntaxError(this, offendingToken, line, charPositionInLine, msg, e);
}
/** Consume the current symbol and return it. E.g., given the following
* input with A being the current lookahead symbol:
*
* A B
* ^
*
* this function moves the cursor to B and returns A.
*
* If the parser is creating parse trees, the current symbol
* would also be added as a child to the current context (node).
*
* Trigger listener events if there's a listener.
*/
public Token consume() {
Token o = getCurrentToken();
if (o.getType() != EOF) {
getInputStream().consume();
}
boolean hasListener = _parseListeners != null && !_parseListeners.isEmpty();
if (_buildParseTrees || hasListener) {
if ( _errHandler.inErrorRecoveryMode(this) ) {
ErrorNode node = _ctx.addErrorNode(o);
if (_parseListeners != null) {
for (ParseTreeListener listener : _parseListeners) {
listener.visitErrorNode(node);
}
}
}
else {
TerminalNode node = _ctx.addChild(o);
if (_parseListeners != null) {
for (ParseTreeListener listener : _parseListeners) {
listener.visitTerminal(node);
}
}
}
}
return o;
}
protected void addContextToParseTree() {
ParserRuleContext parent = (ParserRuleContext)_ctx.parent;
// add current context to parent if we have a parent
if ( parent!=null ) {
parent.addChild(_ctx);
}
}
/** Always called by generated parsers upon entry to a rule.
* This occurs after the new context has been pushed. Access field
* _ctx get the current context.
*
* This is flexible because users do not have to regenerate parsers
* to get trace facilities.
*/
public void enterRule(ParserRuleContext localctx, int state, int ruleIndex) {
setState(state);
_ctx = localctx;
_ctx.start = _input.LT(1);
if (_buildParseTrees) addContextToParseTree();
if ( _parseListeners != null) triggerEnterRuleEvent();
}
public void exitRule() {
_ctx.stop = _input.LT(-1);
// trigger event on _ctx, before it reverts to parent
if ( _parseListeners != null) triggerExitRuleEvent();
setState(_ctx.invokingState);
_ctx = (ParserRuleContext)_ctx.parent;
}
public void enterOuterAlt(ParserRuleContext localctx, int altNum) {
// if we have new localctx, make sure we replace existing ctx
// that is previous child of parse tree
if ( _buildParseTrees && _ctx != localctx ) {
ParserRuleContext parent = (ParserRuleContext)_ctx.parent;
if ( parent!=null ) {
parent.removeLastChild();
parent.addChild(localctx);
}
}
_ctx = localctx;
_ctx.altNum = altNum;
}
public void enterRecursionRule(ParserRuleContext localctx, int ruleIndex) {
_ctx = localctx;
_ctx.start = _input.LT(1);
if (_parseListeners != null) {
triggerEnterRuleEvent(); // simulates rule entry for left-recursive rules
}
}
/* like enterRule but for recursive rules */
public void pushNewRecursionContext(ParserRuleContext localctx, int state, int ruleIndex) {
ParserRuleContext previous = _ctx;
previous.parent = localctx;
previous.invokingState = state;
previous.stop = _input.LT(-1);
_ctx = localctx;
_ctx.start = previous.start;
if (_buildParseTrees) {
_ctx.addChild(previous);
}
if ( _parseListeners != null ) {
triggerEnterRuleEvent(); // simulates rule entry for left-recursive rules
}
}
public void unrollRecursionContexts(ParserRuleContext _parentctx) {
_ctx.stop = _input.LT(-1);
ParserRuleContext retctx = _ctx; // save current ctx (return value)
// unroll so _ctx is as it was before call to recursive method
if ( _parseListeners != null ) {
while ( _ctx != _parentctx ) {
triggerExitRuleEvent();
_ctx = (ParserRuleContext)_ctx.parent;
}
}
else {
_ctx = _parentctx;
}
// hook into tree
retctx.parent = _parentctx;
if (_buildParseTrees) _parentctx.addChild(retctx); // add return ctx into invoking rule's tree
}
public ParserRuleContext getInvokingContext(int ruleIndex) {
ParserRuleContext p = _ctx;
while ( p!=null ) {
if ( p.getRuleIndex() == ruleIndex ) return p;
p = (ParserRuleContext)p.parent;
}
return null;
}
public ParserRuleContext getContext() {
return _ctx;
}
public boolean inContext(String context) {
// TODO: useful in parser?
return false;
}
public boolean isExpectedToken(int symbol) {
// return getInterpreter().atn.nextTokens(_ctx);
ATN atn = getInterpreter().atn;
ParserRuleContext ctx = _ctx;
ATNState s = atn.states.get(getState());
IntervalSet following = atn.nextTokens(s);
if (following.contains(symbol)) {
return true;
}
// System.out.println("following "+s+"="+following);
if ( !following.contains(Token.EPSILON) ) return false;
while ( ctx!=null && ctx.invokingState>=0 && following.contains(Token.EPSILON) ) {
ATNState invokingState = atn.states.get(ctx.invokingState);
RuleTransition rt = (RuleTransition)invokingState.transition(0);
following = atn.nextTokens(rt.followState);
if (following.contains(symbol)) {
return true;
}
ctx = (ParserRuleContext)ctx.parent;
}
if ( following.contains(Token.EPSILON) && symbol == Token.EOF ) {
return true;
}
return false;
}
/** Compute the set of valid tokens reachable from the current
* position in the parse.
*/
public IntervalSet getExpectedTokens() {
ATN atn = getInterpreter().atn;
ParserRuleContext ctx = _ctx;
ATNState s = atn.states.get(getState());
IntervalSet following = atn.nextTokens(s);
// System.out.println("following "+s+"="+following);
if ( !following.contains(Token.EPSILON) ) return following;
IntervalSet expected = new IntervalSet();
expected.addAll(following);
expected.remove(Token.EPSILON);
while ( ctx!=null && ctx.invokingState>=0 && following.contains(Token.EPSILON) ) {
ATNState invokingState = atn.states.get(ctx.invokingState);
RuleTransition rt = (RuleTransition)invokingState.transition(0);
following = atn.nextTokens(rt.followState);
expected.addAll(following);
expected.remove(Token.EPSILON);
ctx = (ParserRuleContext)ctx.parent;
}
if ( following.contains(Token.EPSILON) ) {
expected.add(Token.EOF);
}
return expected;
}
public IntervalSet getExpectedTokensWithinCurrentRule() {
ATN atn = getInterpreter().atn;
ATNState s = atn.states.get(getState());
return atn.nextTokens(s);
}
// /** Compute the set of valid tokens reachable from the current
// * position in the parse.
// */
// public IntervalSet nextTokens(@NotNull RuleContext ctx) {
// ATN atn = getInterpreter().atn;
// ATNState s = atn.states.get(ctx.s);
// if ( s == null ) return null;
// return atn.nextTokens(s, ctx);
// }
public ParserRuleContext getRuleContext() { return _ctx; }
/** Return List of the rule names in your parser instance
* leading up to a call to the current rule. You could override if
* you want more details such as the file/line info of where
* in the ATN a rule is invoked.
*
* This is very useful for error messages.
*/
public List getRuleInvocationStack() {
return getRuleInvocationStack(_ctx);
}
public List getRuleInvocationStack(RuleContext p) {
String[] ruleNames = getRuleNames();
List stack = new ArrayList();
while ( p!=null ) {
// compute what follows who invoked us
int ruleIndex = p.getRuleIndex();
if ( ruleIndex<0 ) stack.add("n/a");
else stack.add(ruleNames[ruleIndex]);
p = p.parent;
}
return stack;
}
/** For debugging and other purposes */
public List getDFAStrings() {
synchronized (_interp.decisionToDFA) {
List s = new ArrayList();
for (int d = 0; d < _interp.decisionToDFA.length; d++) {
DFA dfa = _interp.decisionToDFA[d];
s.add( dfa.toString(getTokenNames()) );
}
return s;
}
}
/** For debugging and other purposes */
public void dumpDFA() {
synchronized (_interp.decisionToDFA) {
boolean seenOne = false;
for (int d = 0; d < _interp.decisionToDFA.length; d++) {
DFA dfa = _interp.decisionToDFA[d];
if ( dfa!=null ) {
if ( seenOne ) System.out.println();
System.out.println("Decision " + dfa.decision + ":");
System.out.print(dfa.toString(getTokenNames()));
seenOne = true;
}
}
}
}
public String getSourceName() {
return _input.getSourceName();
}
/** A convenience method for use most often with template rewrites.
* Convert a List to List
*/
public List toStrings(List tokens) {
if ( tokens==null ) return null;
List strings = new ArrayList(tokens.size());
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