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ANTLR Runtime Source Code
ANTLR is a powerful parser generator for multiple programming languages including Java.
ANTLR contains 2 major modules:
ANTLR Runtime Source Code files are provided in the distribution packge (antlr4-4.10.1.zip). You can download them at ANTLR Website.
You can also browse the source code below:
✍: FYIcenter
⏎ org/antlr/v4/runtime/tree/xpath/XPath.java
/* * Copyright (c) 2012-2017 The ANTLR Project. All rights reserved. * Use of this file is governed by the BSD 3-clause license that * can be found in the LICENSE.txt file in the project root. */ package org.antlr.v4.runtime.tree.xpath; import org.antlr.v4.runtime.ANTLRInputStream; import org.antlr.v4.runtime.CommonTokenStream; import org.antlr.v4.runtime.LexerNoViableAltException; import org.antlr.v4.runtime.Parser; import org.antlr.v4.runtime.ParserRuleContext; import org.antlr.v4.runtime.Token; import org.antlr.v4.runtime.tree.ParseTree; import java.io.IOException; import java.io.StringReader; import java.util.ArrayList; import java.util.Collection; import java.util.Collections; import java.util.LinkedHashSet; import java.util.List; /** * Represent a subset of XPath XML path syntax for use in identifying nodes in * parse trees. * * <p> * Split path into words and separators {@code /} and {@code //} via ANTLR * itself then walk path elements from left to right. At each separator-word * pair, find set of nodes. Next stage uses those as work list.</p> * * <p> * The basic interface is * {@link XPath#findAll ParseTree.findAll}{@code (tree, pathString, parser)}. * But that is just shorthand for:</p> * * <pre> * {@link XPath} p = new {@link XPath#XPath XPath}(parser, pathString); * return p.{@link #evaluate evaluate}(tree); * </pre> * * <p> * See {@code org.antlr.v4.test.TestXPath} for descriptions. In short, this * allows operators:</p> * * <dl> * <dt>/</dt> <dd>root</dd> * <dt>//</dt> <dd>anywhere</dd> * <dt>!</dt> <dd>invert; this must appear directly after root or anywhere * operator</dd> * </dl> * * <p> * and path elements:</p> * * <dl> * <dt>ID</dt> <dd>token name</dd> * <dt>'string'</dt> <dd>any string literal token from the grammar</dd> * <dt>expr</dt> <dd>rule name</dd> * <dt>*</dt> <dd>wildcard matching any node</dd> * </dl> * * <p> * Whitespace is not allowed.</p> */ public class XPath { public static final String WILDCARD = "*"; // word not operator/separator public static final String NOT = "!"; // word for invert operator protected String path; protected XPathElement[] elements; protected Parser parser; public XPath(Parser parser, String path) { this.parser = parser; this.path = path; elements = split(path); // System.out.println(Arrays.toString(elements)); } // TODO: check for invalid token/rule names, bad syntax public XPathElement[] split(String path) { ANTLRInputStream in; try { in = new ANTLRInputStream(new StringReader(path)); } catch (IOException ioe) { throw new IllegalArgumentException("Could not read path: "+path, ioe); } XPathLexer lexer = new XPathLexer(in) { @Override public void recover(LexerNoViableAltException e) { throw e; } }; lexer.removeErrorListeners(); lexer.addErrorListener(new XPathLexerErrorListener()); CommonTokenStream tokenStream = new CommonTokenStream(lexer); try { tokenStream.fill(); } catch (LexerNoViableAltException e) { int pos = lexer.getCharPositionInLine(); String msg = "Invalid tokens or characters at index "+pos+" in path '"+path+"'"; throw new IllegalArgumentException(msg, e); } List<Token> tokens = tokenStream.getTokens(); // System.out.println("path="+path+"=>"+tokens); List<XPathElement> elements = new ArrayList<XPathElement>(); int n = tokens.size(); int i=0; loop: while ( i<n ) { Token el = tokens.get(i); Token next = null; switch ( el.getType() ) { case XPathLexer.ROOT : case XPathLexer.ANYWHERE : boolean anywhere = el.getType() == XPathLexer.ANYWHERE; i++; next = tokens.get(i); boolean invert = next.getType()==XPathLexer.BANG; if ( invert ) { i++; next = tokens.get(i); } XPathElement pathElement = getXPathElement(next, anywhere); pathElement.invert = invert; elements.add(pathElement); i++; break; case XPathLexer.TOKEN_REF : case XPathLexer.RULE_REF : case XPathLexer.WILDCARD : elements.add( getXPathElement(el, false) ); i++; break; case Token.EOF : break loop; default : throw new IllegalArgumentException("Unknowth path element "+el); } } return elements.toArray(new XPathElement[0]); } /** * Convert word like {@code *} or {@code ID} or {@code expr} to a path * element. {@code anywhere} is {@code true} if {@code //} precedes the * word. */ protected XPathElement getXPathElement(Token wordToken, boolean anywhere) { if ( wordToken.getType()==Token.EOF ) { throw new IllegalArgumentException("Missing path element at end of path"); } String word = wordToken.getText(); int ttype = parser.getTokenType(word); int ruleIndex = parser.getRuleIndex(word); switch ( wordToken.getType() ) { case XPathLexer.WILDCARD : return anywhere ? new XPathWildcardAnywhereElement() : new XPathWildcardElement(); case XPathLexer.TOKEN_REF : case XPathLexer.STRING : if ( ttype==Token.INVALID_TYPE ) { throw new IllegalArgumentException(word+ " at index "+ wordToken.getStartIndex()+ " isn't a valid token name"); } return anywhere ? new XPathTokenAnywhereElement(word, ttype) : new XPathTokenElement(word, ttype); default : if ( ruleIndex==-1 ) { throw new IllegalArgumentException(word+ " at index "+ wordToken.getStartIndex()+ " isn't a valid rule name"); } return anywhere ? new XPathRuleAnywhereElement(word, ruleIndex) : new XPathRuleElement(word, ruleIndex); } } public static Collection<ParseTree> findAll(ParseTree tree, String xpath, Parser parser) { XPath p = new XPath(parser, xpath); return p.evaluate(tree); } /** * Return a list of all nodes starting at {@code t} as root that satisfy the * path. The root {@code /} is relative to the node passed to * {@link #evaluate}. */ public Collection<ParseTree> evaluate(final ParseTree t) { ParserRuleContext dummyRoot = new ParserRuleContext(); dummyRoot.children = Collections.singletonList(t); // don't set t's parent. Collection<ParseTree> work = Collections.<ParseTree>singleton(dummyRoot); int i = 0; while ( i < elements.length ) { Collection<ParseTree> next = new LinkedHashSet<ParseTree>(); for (ParseTree node : work) { if ( node.getChildCount()>0 ) { // only try to match next element if it has children // e.g., //func/*/stat might have a token node for which // we can't go looking for stat nodes. Collection<? extends ParseTree> matching = elements[i].evaluate(node); next.addAll(matching); } } i++; work = next; } return work; } }
⏎ org/antlr/v4/runtime/tree/xpath/XPath.java
Or download all of them as a single archive file:
File name: antlr-runtime-4.10.1-sources.jar File size: 308953 bytes Release date: 2022-04-15 Download
⇐ What Is ANTLR Parser Generator
2018-10-21, 31720👍, 0💬
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