1324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver/* 2324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * [The "BSD license"] 3324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * Copyright (c) 2010 Terence Parr 4324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * All rights reserved. 5324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * 6324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * Redistribution and use in source and binary forms, with or without 7324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * modification, are permitted provided that the following conditions 8324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * are met: 9324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * 1. Redistributions of source code must retain the above copyright 10324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * notice, this list of conditions and the following disclaimer. 11324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * 2. Redistributions in binary form must reproduce the above copyright 12324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * notice, this list of conditions and the following disclaimer in the 13324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * documentation and/or other materials provided with the distribution. 14324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * 3. The name of the author may not be used to endorse or promote products 15324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * derived from this software without specific prior written permission. 16324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * 17324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver */ 28324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruverpackage org.antlr.analysis; 29324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 30324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruverimport org.antlr.misc.Utils; 31324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 32324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver/** An NFA state, predicted alt, and syntactic/semantic context. 33324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * The syntactic context is a pointer into the rule invocation 34324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * chain used to arrive at the state. The semantic context is 35324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * the unordered set semantic predicates encountered before reaching 36324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * an NFA state. 37324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver */ 38324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruverpublic class NFAConfiguration { 39324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver /** The NFA state associated with this configuration */ 40324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver public int state; 41324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 42324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver /** What alt is predicted by this configuration */ 43324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver public int alt; 44324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 45324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver /** What is the stack of rule invocations that got us to state? */ 46324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver public NFAContext context; 47324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 48324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver /** The set of semantic predicates associated with this NFA 49324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * configuration. The predicates were found on the way to 50324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * the associated NFA state in this syntactic context. 51324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * Set<AST>: track nodes in grammar containing the predicate 52324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * for error messages and such (nice to know where the predicate 53324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * came from in case of duplicates etc...). By using a set, 54324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * the equals() method will correctly show {pred1,pred2} as equals() 55324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * to {pred2,pred1}. 56324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver */ 57324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver public SemanticContext semanticContext = SemanticContext.EMPTY_SEMANTIC_CONTEXT; 58324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 59324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver /** Indicate that this configuration has been resolved and no further 60324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * DFA processing should occur with it. Essentially, this is used 61324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * as an "ignore" bit so that upon a set of nondeterministic configurations 62324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * such as (s|2) and (s|3), I can set (s|3) to resolved=true (and any 63324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * other configuration associated with alt 3). 64324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver */ 65324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver protected boolean resolved; 66324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 67324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver /** This bit is used to indicate a semantic predicate will be 68324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * used to resolve the conflict. Method 69324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * DFA.findNewDFAStatesAndAddDFATransitions will add edges for 70324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * the predicates after it performs the reach operation. The 71324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * nondeterminism resolver sets this when it finds a set of 72324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * nondeterministic configurations (as it does for "resolved" field) 73324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * that have enough predicates to resolve the conflit. 74324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver */ 75324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver protected boolean resolveWithPredicate; 76324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 77324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver /** Lots of NFA states have only epsilon edges (1 or 2). We can 78324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * safely consider only n>0 during closure. 79324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver */ 80324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver protected int numberEpsilonTransitionsEmanatingFromState; 81324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 82324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver /** Indicates that the NFA state associated with this configuration 83324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * has exactly one transition and it's an atom (not epsilon etc...). 84324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver */ 85324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver protected boolean singleAtomTransitionEmanating; 86324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 87324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver //protected boolean addedDuringClosure = true; 88324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 89324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver public NFAConfiguration(int state, 90324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver int alt, 91324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver NFAContext context, 92324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver SemanticContext semanticContext) 93324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver { 94324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver this.state = state; 95324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver this.alt = alt; 96324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver this.context = context; 97324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver this.semanticContext = semanticContext; 98324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver } 99324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 100324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver /** An NFA configuration is equal to another if both have 101324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * the same state, the predict the same alternative, and 102324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * syntactic/semantic contexts are the same. I don't think 103324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * the state|alt|ctx could be the same and have two different 104324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * semantic contexts, but might as well define equals to be 105324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * everything. 106324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver */ 107324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver public boolean equals(Object o) { 108324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver if ( o==null ) { 109324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver return false; 110324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver } 111324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver NFAConfiguration other = (NFAConfiguration)o; 112324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver return this.state==other.state && 113324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver this.alt==other.alt && 114324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver this.context.equals(other.context)&& 115324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver this.semanticContext.equals(other.semanticContext); 116324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver } 117324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 118324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver public int hashCode() { 119324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver int h = state + alt + context.hashCode(); 120324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver return h; 121324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver } 122324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 123324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver public String toString() { 124324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver return toString(true); 125324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver } 126324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 127324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver public String toString(boolean showAlt) { 128324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver StringBuffer buf = new StringBuffer(); 129324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver buf.append(state); 130324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver if ( showAlt ) { 131324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver buf.append("|"); 132324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver buf.append(alt); 133324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver } 134324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver if ( context.parent!=null ) { 135324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver buf.append("|"); 136324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver buf.append(context); 137324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver } 138324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver if ( semanticContext!=null && 139324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver semanticContext!=SemanticContext.EMPTY_SEMANTIC_CONTEXT ) { 140324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver buf.append("|"); 141324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver String escQuote = Utils.replace(semanticContext.toString(), "\"", "\\\""); 142324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver buf.append(escQuote); 143324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver } 144324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver if ( resolved ) { 145324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver buf.append("|resolved"); 146324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver } 147324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver if ( resolveWithPredicate ) { 148324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver buf.append("|resolveWithPredicate"); 149324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver } 150324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver return buf.toString(); 151324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver } 152324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver} 153