PredicateLabel.java revision 324c4644fee44b9898524c09511bd33c3f12e2df
1/* 2 * [The "BSD license"] 3 * Copyright (c) 2010 Terence Parr 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. The name of the author may not be used to endorse or promote products 15 * derived from this software without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 */ 28package org.antlr.analysis; 29 30import org.antlr.tool.Grammar; 31import org.antlr.tool.GrammarAST; 32 33public class PredicateLabel extends Label { 34 /** A tree of semantic predicates from the grammar AST if label==SEMPRED. 35 * In the NFA, labels will always be exactly one predicate, but the DFA 36 * may have to combine a bunch of them as it collects predicates from 37 * multiple NFA configurations into a single DFA state. 38 */ 39 protected SemanticContext semanticContext; 40 41 /** Make a semantic predicate label */ 42 public PredicateLabel(GrammarAST predicateASTNode) { 43 super(SEMPRED); 44 this.semanticContext = new SemanticContext.Predicate(predicateASTNode); 45 } 46 47 /** Make a semantic predicates label */ 48 public PredicateLabel(SemanticContext semCtx) { 49 super(SEMPRED); 50 this.semanticContext = semCtx; 51 } 52 53 public int hashCode() { 54 return semanticContext.hashCode(); 55 } 56 57 public boolean equals(Object o) { 58 if ( o==null ) { 59 return false; 60 } 61 if ( this == o ) { 62 return true; // equals if same object 63 } 64 if ( !(o instanceof PredicateLabel) ) { 65 return false; 66 } 67 return semanticContext.equals(((PredicateLabel)o).semanticContext); 68 } 69 70 public boolean isSemanticPredicate() { 71 return true; 72 } 73 74 public SemanticContext getSemanticContext() { 75 return semanticContext; 76 } 77 78 public String toString() { 79 return "{"+semanticContext+"}?"; 80 } 81 82 public String toString(Grammar g) { 83 return toString(); 84 } 85} 86