| /* |
| [The "BSD license"] |
| Copyright (c) 2005-2009 Terence Parr |
| 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.runtime.tree; |
| |
| import org.antlr.runtime.*; |
| |
| import java.util.regex.Matcher; |
| import java.util.regex.Pattern; |
| |
| /** A parser for a stream of tree nodes. "tree grammars" result in a subclass |
| * of this. All the error reporting and recovery is shared with Parser via |
| * the BaseRecognizer superclass. |
| */ |
| public class TreeParser extends BaseRecognizer { |
| public static final int DOWN = Token.DOWN; |
| public static final int UP = Token.UP; |
| |
| // precompiled regex used by inContext |
| static String dotdot = ".*[^.]\\.\\.[^.].*"; |
| static String doubleEtc = ".*\\.\\.\\.\\s+\\.\\.\\..*"; |
| static Pattern dotdotPattern = Pattern.compile(dotdot); |
| static Pattern doubleEtcPattern = Pattern.compile(doubleEtc); |
| |
| protected TreeNodeStream input; |
| |
| public TreeParser(TreeNodeStream input) { |
| super(); // highlight that we go to super to set state object |
| setTreeNodeStream(input); |
| } |
| |
| public TreeParser(TreeNodeStream input, RecognizerSharedState state) { |
| super(state); // share the state object with another parser |
| setTreeNodeStream(input); |
| } |
| |
| @Override |
| public void reset() { |
| super.reset(); // reset all recognizer state variables |
| if ( input!=null ) { |
| input.seek(0); // rewind the input |
| } |
| } |
| |
| /** Set the input stream */ |
| public void setTreeNodeStream(TreeNodeStream input) { |
| this.input = input; |
| } |
| |
| public TreeNodeStream getTreeNodeStream() { |
| return input; |
| } |
| |
| @Override |
| public String getSourceName() { |
| return input.getSourceName(); |
| } |
| |
| @Override |
| protected Object getCurrentInputSymbol(IntStream input) { |
| return ((TreeNodeStream)input).LT(1); |
| } |
| |
| @Override |
| protected Object getMissingSymbol(IntStream input, |
| RecognitionException e, |
| int expectedTokenType, |
| BitSet follow) |
| { |
| String tokenText = |
| "<missing "+getTokenNames()[expectedTokenType]+">"; |
| TreeAdaptor adaptor = ((TreeNodeStream)e.input).getTreeAdaptor(); |
| return adaptor.create(new CommonToken(expectedTokenType, tokenText)); |
| } |
| |
| /** Match '.' in tree parser has special meaning. Skip node or |
| * entire tree if node has children. If children, scan until |
| * corresponding UP node. |
| */ |
| @Override |
| public void matchAny(IntStream ignore) { // ignore stream, copy of input |
| state.errorRecovery = false; |
| state.failed = false; |
| Object look = input.LT(1); |
| if ( input.getTreeAdaptor().getChildCount(look)==0 ) { |
| input.consume(); // not subtree, consume 1 node and return |
| return; |
| } |
| // current node is a subtree, skip to corresponding UP. |
| // must count nesting level to get right UP |
| int level=0; |
| int tokenType = input.getTreeAdaptor().getType(look); |
| while ( tokenType!=Token.EOF && !(tokenType==UP && level==0) ) { |
| input.consume(); |
| look = input.LT(1); |
| tokenType = input.getTreeAdaptor().getType(look); |
| if ( tokenType == DOWN ) { |
| level++; |
| } |
| else if ( tokenType == UP ) { |
| level--; |
| } |
| } |
| input.consume(); // consume UP |
| } |
| |
| /** We have DOWN/UP nodes in the stream that have no line info; override. |
| * plus we want to alter the exception type. Don't try to recover |
| * from tree parser errors inline... |
| */ |
| @Override |
| protected Object recoverFromMismatchedToken(IntStream input, |
| int ttype, |
| BitSet follow) |
| throws RecognitionException |
| { |
| throw new MismatchedTreeNodeException(ttype, (TreeNodeStream)input); |
| } |
| |
| /** Prefix error message with the grammar name because message is |
| * always intended for the programmer because the parser built |
| * the input tree not the user. |
| */ |
| @Override |
| public String getErrorHeader(RecognitionException e) { |
| return getGrammarFileName()+": node from "+ |
| (e.approximateLineInfo?"after ":"")+"line "+e.line+":"+e.charPositionInLine; |
| } |
| |
| /** Tree parsers parse nodes they usually have a token object as |
| * payload. Set the exception token and do the default behavior. |
| */ |
| @Override |
| public String getErrorMessage(RecognitionException e, String[] tokenNames) { |
| if ( this instanceof TreeParser ) { |
| TreeAdaptor adaptor = ((TreeNodeStream)e.input).getTreeAdaptor(); |
| e.token = adaptor.getToken(e.node); |
| if ( e.token==null ) { // could be an UP/DOWN node |
| e.token = new CommonToken(adaptor.getType(e.node), |
| adaptor.getText(e.node)); |
| } |
| } |
| return super.getErrorMessage(e, tokenNames); |
| } |
| |
| /** Check if current node in input has a context. Context means sequence |
| * of nodes towards root of tree. For example, you might say context |
| * is "MULT" which means my parent must be MULT. "CLASS VARDEF" says |
| * current node must be child of a VARDEF and whose parent is a CLASS node. |
| * You can use "..." to mean zero-or-more nodes. "METHOD ... VARDEF" |
| * means my parent is VARDEF and somewhere above that is a METHOD node. |
| * The first node in the context is not necessarily the root. The context |
| * matcher stops matching and returns true when it runs out of context. |
| * There is no way to force the first node to be the root. |
| */ |
| public boolean inContext(String context) { |
| return inContext(input.getTreeAdaptor(), getTokenNames(), input.LT(1), context); |
| } |
| |
| /** The worker for inContext. It's static and full of parameters for |
| * testing purposes. |
| */ |
| public static boolean inContext(TreeAdaptor adaptor, |
| String[] tokenNames, |
| Object t, |
| String context) |
| { |
| Matcher dotdotMatcher = dotdotPattern.matcher(context); |
| Matcher doubleEtcMatcher = doubleEtcPattern.matcher(context); |
| if ( dotdotMatcher.find() ) { // don't allow "..", must be "..." |
| throw new IllegalArgumentException("invalid syntax: .."); |
| } |
| if ( doubleEtcMatcher.find() ) { // don't allow double "..." |
| throw new IllegalArgumentException("invalid syntax: ... ..."); |
| } |
| context = context.replaceAll("\\.\\.\\.", " ... "); // ensure spaces around ... |
| context = context.trim(); |
| String[] nodes = context.split("\\s+"); |
| int ni = nodes.length-1; |
| t = adaptor.getParent(t); |
| while ( ni>=0 && t!=null ) { |
| if ( nodes[ni].equals("...") ) { |
| // walk upwards until we see nodes[ni-1] then continue walking |
| if ( ni==0 ) return true; // ... at start is no-op |
| String goal = nodes[ni-1]; |
| Object ancestor = getAncestor(adaptor, tokenNames, t, goal); |
| if ( ancestor==null ) return false; |
| t = ancestor; |
| ni--; |
| } |
| String name = tokenNames[adaptor.getType(t)]; |
| if ( !name.equals(nodes[ni]) ) { |
| //System.err.println("not matched: "+nodes[ni]+" at "+t); |
| return false; |
| } |
| // advance to parent and to previous element in context node list |
| ni--; |
| t = adaptor.getParent(t); |
| } |
| |
| if ( t==null && ni>=0 ) return false; // at root but more nodes to match |
| return true; |
| } |
| |
| /** Helper for static inContext */ |
| protected static Object getAncestor(TreeAdaptor adaptor, String[] tokenNames, Object t, String goal) { |
| while ( t!=null ) { |
| String name = tokenNames[adaptor.getType(t)]; |
| if ( name.equals(goal) ) return t; |
| t = adaptor.getParent(t); |
| } |
| return null; |
| } |
| |
| public void traceIn(String ruleName, int ruleIndex) { |
| super.traceIn(ruleName, ruleIndex, input.LT(1)); |
| } |
| |
| public void traceOut(String ruleName, int ruleIndex) { |
| super.traceOut(ruleName, ruleIndex, input.LT(1)); |
| } |
| } |