C# Grammar.CreateLookaheadDFAs方法代码示例

 public void TestSimpleRangeVersusChar()
 {
     Grammar g = new Grammar(
         "lexer grammar t;\n" +
         "A : 'a'..'z' '@' | 'k' '$' ;" );
     g.CreateLookaheadDFAs();
     string expecting =
         ".s0-'k'->.s1" + NewLine +
         ".s0-{'a'..'j', 'l'..'z'}->:s2=>1" + NewLine +
         ".s1-'$'->:s3=>2" + NewLine +
         ".s1-'@'->:s2=>1" + NewLine;
     checkDecision( g, 1, expecting, null );
 }

        //throws Exception
        protected void checkDecision( Grammar g,
                                     int decision,
                                     string expecting,
                                     int[] expectingUnreachableAlts )
        {
            Antlr3.AntlrTool tool = new Antlr3.AntlrTool();
            // mimic actions of org.antlr.Tool first time for grammar g
            if ( g.CodeGenerator == null )
            {
                CodeGenerator generator = new CodeGenerator( tool, g, "Java" );
                g.CodeGenerator = generator;
                g.BuildNFA();
                g.CreateLookaheadDFAs( false );
            }

            DFA dfa = g.GetLookaheadDFA( decision );
            Assert.IsNotNull(dfa, "unknown decision #" + decision);
            FASerializer serializer = new FASerializer( g );
            string result = serializer.Serialize( dfa.StartState );
            //System.out.print(result);
            var nonDetAlts = dfa.UnreachableAlts;
            //System.out.println("alts w/o predict state="+nonDetAlts);

            // first make sure nondeterministic alts are as expected
            if ( expectingUnreachableAlts == null )
            {
                if ( nonDetAlts != null && nonDetAlts.Count != 0 )
                {
                    Console.Error.WriteLine( "nondeterministic alts (should be empty): " + ( (IList)nonDetAlts ).ToElementString() );
                }
                Assert.AreEqual(0, nonDetAlts != null ? nonDetAlts.Count : 0, "unreachable alts mismatch");
            }
            else
            {
                for ( int i = 0; i < expectingUnreachableAlts.Length; i++ )
                {
                    Assert.IsTrue(nonDetAlts != null ? nonDetAlts.Contains(expectingUnreachableAlts[i]) : false, "unreachable alts mismatch");
                }
            }
            Assert.AreEqual( expecting, result );
        }

 public void TestRecursive()
 {
     // this is cool because the 3rd alt includes !(all other possibilities)
     Grammar g = new Grammar(
         "lexer grammar duh;\n" +
         "SUBTEMPLATE\n" +
         "        :       '{'\n" +
         "                ( SUBTEMPLATE\n" +
         "                | ESC\n" +
         "                | ~('}'|'\\\\'|'{')\n" +
         "                )*\n" +
         "                '}'\n" +
         "        ;\n" +
         "fragment\n" +
         "ESC     :       '\\\\' . ;" );
     g.CreateLookaheadDFAs();
     string expecting =
         ".s0-'\\\\'->:s2=>2" + NewLine +
         ".s0-'{'->:s1=>1" + NewLine +
         ".s0-'}'->:s4=>4" + NewLine +
         ".s0-{'\\u0000'..'[', ']'..'z', '|', '~'..'\\uFFFF'}->:s3=>3" + NewLine;
     checkDecision( g, 1, expecting, null );
 }

 public void TestRecursive2()
 {
     // this is also cool because it resolves \\ to be ESC alt; it's just
     // less efficient of a DFA
     Grammar g = new Grammar(
         "lexer grammar duh;\n" +
         "SUBTEMPLATE\n" +
         "        :       '{'\n" +
         "                ( SUBTEMPLATE\n" +
         "                | ESC\n" +
         "                | ~('}'|'{')\n" +
         "                )*\n" +
         "                '}'\n" +
         "        ;\n" +
         "fragment\n" +
         "ESC     :       '\\\\' . ;" );
     g.CreateLookaheadDFAs();
     string expecting =
         ".s0-'\\\\'->.s3" + NewLine +
         ".s0-'{'->:s2=>1" + NewLine +
         ".s0-'}'->:s1=>4" + NewLine +
         ".s0-{'\\u0000'..'[', ']'..'z', '|', '~'..'\\uFFFF'}->:s5=>3" + NewLine +
         ".s3-'\\\\'->:s8=>2" + NewLine +
         ".s3-'{'->:s7=>2" + NewLine +
         ".s3-'}'->.s4" + NewLine +
         ".s3-{'\\u0000'..'[', ']'..'z', '|', '~'..'\\uFFFF'}->:s6=>2" + NewLine +
         ".s4-'\\u0000'..'\\uFFFF'->:s6=>2" + NewLine +
         ".s4-<EOT>->:s5=>3" + NewLine;
     checkDecision( g, 1, expecting, null );
 }

 public void TestNotTokenInLexer()
 {
     Grammar g = new Grammar(
         "lexer grammar T;\n" +
         "A : 'x' ('a' | ~B {;}) ;\n" +
         "B : 'a' ;\n" );
     g.CreateLookaheadDFAs();
     string expecting =
         ".s0-'a'->:s1=>1" + NewLine +
         ".s0-{'\\u0000'..'`', 'b'..'\\uFFFF'}->:s2=>2" + NewLine;
     checkDecision( g, 1, expecting, null );
 }

 public void TestRangeWithDisjointSet()
 {
     Grammar g = new Grammar(
         "lexer grammar t;\n" +
         "A : 'a'..'z' '@'\n" +
         "  | ('k'|'9'|'p') '$'\n" +
         "  ;\n" );
     g.CreateLookaheadDFAs();
     // must break up a..z into {'a'..'j', 'l'..'o', 'q'..'z'}
     string expecting =
         ".s0-'9'->:s3=>2" + NewLine +
         ".s0-{'a'..'j', 'l'..'o', 'q'..'z'}->:s2=>1" + NewLine +
         ".s0-{'k', 'p'}->.s1" + NewLine +
         ".s1-'$'->:s3=>2" + NewLine +
         ".s1-'@'->:s2=>1" + NewLine;
     checkDecision( g, 1, expecting, null );
 }

 public void TestDisjointSetCollidingWithTwoRanges()
 {
     Grammar g = new Grammar(
         "lexer grammar t;\n" +
         "A : ('a'..'z'|'0'..'9') '@'\n" +
         "  | ('k'|'9'|'p') '$'\n" +
         "  ;\n" );
     g.CreateLookaheadDFAs( false );
     // must break up a..z into {'a'..'j', 'l'..'o', 'q'..'z'} and 0..9
     // into 0..8
     string expecting =
         ".s0-{'0'..'8', 'a'..'j', 'l'..'o', 'q'..'z'}->:s2=>1" + NewLine +
         ".s0-{'9', 'k', 'p'}->.s1" + NewLine +
         ".s1-'$'->:s3=>2" + NewLine +
         ".s1-'@'->:s2=>1" + NewLine;
     checkDecision( g, 1, expecting, null );
 }

 public void TestNotSetFragmentInLexer()
 {
     Grammar g = new Grammar(
         "lexer grammar T;\n" +
         "A : B | ~B {;} ;\n" +
         "fragment B : 'a'|'b' ;\n" );
     g.CreateLookaheadDFAs();
     string expecting =
         ".s0-'a'..'b'->:s1=>1" + NewLine +
         ".s0-{'\\u0000'..'`', 'c'..'\\uFFFF'}->:s2=>2" + NewLine;
     checkDecision( g, 1, expecting, null );
 }

        public void TestPredsUsedAfterRecursionOverflow()
        {
            // analysis must bail out due to non-LL(*) nature (ovf)
            // retries with k=1 (but with LL(*) algorithm not optimized version
            // as it has preds)
            Grammar g = new Grammar(
                "parser grammar P;\n" +
                "s : {p1}? e '.' | {p2}? e ':' ;\n" +
                "e : '(' e ')' | INT ;\n" );
            string expecting =
                ".s0-'('->.s1" + NewLine +
                ".s0-INT->.s4" + NewLine +
                ".s1-{p1}?->:s2=>1" + NewLine +
                ".s1-{p2}?->:s3=>2" + NewLine +
                ".s4-{p1}?->:s2=>1" + NewLine +
                ".s4-{p2}?->:s3=>2" + NewLine;
            DecisionProbe.verbose = true; // make sure we get all error info
            ErrorQueue equeue = new ErrorQueue();
            ErrorManager.SetErrorListener( equeue );
            CodeGenerator generator = new CodeGenerator( newTool(), g, "Java" );
            g.CodeGenerator = generator;
            if ( g.NumberOfDecisions == 0 )
            {
                g.BuildNFA();
                g.CreateLookaheadDFAs( false );
            }

            Assert.AreEqual(0, equeue.size(), "unexpected number of expected problems");
            checkDecision( g, 1, expecting, null, null, null, null, null, 0, false );
        }

        //throws Exception
        protected void checkDecision( Grammar g,
                                     int decision,
                                     string expecting,
                                     int[] expectingUnreachableAlts,
                                     int[] expectingNonDetAlts,
                                     string expectingAmbigInput,
                                     int[] expectingInsufficientPredAlts,
                                     int[] expectingDanglingAlts,
                                     int expectingNumWarnings,
                                     bool hasPredHiddenByAction )
        {
            DecisionProbe.verbose = true; // make sure we get all error info
            ErrorQueue equeue = new ErrorQueue();
            ErrorManager.SetErrorListener( equeue );
            CodeGenerator generator = new CodeGenerator( newTool(), g, "Java" );
            g.CodeGenerator = generator;
            // mimic actions of org.antlr.Tool first time for grammar g
            if ( g.NumberOfDecisions == 0 )
            {
                g.BuildNFA();
                g.CreateLookaheadDFAs( false );
            }

            if ( equeue.size() != expectingNumWarnings )
            {
                Console.Error.WriteLine( "Warnings issued: " + equeue );
            }

            Assert.AreEqual(expectingNumWarnings, equeue.size(), "unexpected number of expected problems");

            DFA dfa = g.GetLookaheadDFA( decision );
            FASerializer serializer = new FASerializer( g );
            string result = serializer.Serialize( dfa.StartState );
            //System.out.print(result);
            var unreachableAlts = dfa.UnreachableAlts;

            // make sure unreachable alts are as expected
            if ( expectingUnreachableAlts != null )
            {
                BitSet s = new BitSet();
                s.AddAll( expectingUnreachableAlts );
                BitSet s2 = new BitSet();
                s2.AddAll( unreachableAlts );
                Assert.AreEqual(s, s2, "unreachable alts mismatch");
            }
            else
            {
                Assert.AreEqual(0, unreachableAlts != null ? unreachableAlts.Count : 0, "unreachable alts mismatch");
            }

            // check conflicting input
            if ( expectingAmbigInput != null )
            {
                // first, find nondet message
                Message msg = getNonDeterminismMessage( equeue.warnings );
                Assert.IsNotNull(msg, "no nondeterminism warning?");
                Assert.IsTrue(msg is GrammarNonDeterminismMessage, "expecting nondeterminism; found " + msg.GetType().Name);
                GrammarNonDeterminismMessage nondetMsg =
                    getNonDeterminismMessage( equeue.warnings );
                var labels =
                    nondetMsg.probe.GetSampleNonDeterministicInputSequence( nondetMsg.problemState );
                string input = nondetMsg.probe.GetInputSequenceDisplay( labels );
                Assert.AreEqual( expectingAmbigInput, input );
            }

            // check nondet alts
            if ( expectingNonDetAlts != null )
            {
                GrammarNonDeterminismMessage nondetMsg =
                    getNonDeterminismMessage( equeue.warnings );
                Assert.IsNotNull(nondetMsg, "found no nondet alts; expecting: " + str(expectingNonDetAlts));
                var nonDetAlts =
                    nondetMsg.probe.GetNonDeterministicAltsForState( nondetMsg.problemState );
                // compare nonDetAlts with expectingNonDetAlts
                BitSet s = new BitSet();
                s.AddAll( expectingNonDetAlts );
                BitSet s2 = new BitSet();
                s2.AddAll( nonDetAlts );
                Assert.AreEqual(s, s2, "nondet alts mismatch");
                Assert.AreEqual(hasPredHiddenByAction, nondetMsg.problemState.Dfa.HasPredicateBlockedByAction, "mismatch between expected hasPredHiddenByAction");
            }
            else
            {
                // not expecting any nondet alts, make sure there are none
                GrammarNonDeterminismMessage nondetMsg =
                    getNonDeterminismMessage( equeue.warnings );
                Assert.IsNull(nondetMsg, "found nondet alts, but expecting none");
            }

            if ( expectingInsufficientPredAlts != null )
            {
                GrammarInsufficientPredicatesMessage insuffPredMsg =
                    getGrammarInsufficientPredicatesMessage( equeue.warnings );
                Assert.IsNotNull(insuffPredMsg, "found no GrammarInsufficientPredicatesMessage alts; expecting: " + str(expectingNonDetAlts));
                var locations = insuffPredMsg.altToLocations;
                var actualAlts = locations.Keys;
                BitSet s = new BitSet();
                s.AddAll( expectingInsufficientPredAlts );
                BitSet s2 = new BitSet();
//.........这里部分代码省略.........

        public void TestLeftRecursivePred()
        {
            // No analysis possible. but probably good to fail.  Not sure we really want
            // left-recursion even if guarded with pred.
            Grammar g = new Grammar(
                "parser grammar P;\n" +
                "s : a ;\n" +
                "a : {p1}? a | ID ;\n" );

            DecisionProbe.verbose = true; // make sure we get all error info
            ErrorQueue equeue = new ErrorQueue();
            ErrorManager.SetErrorListener( equeue );
            CodeGenerator generator = new CodeGenerator( newTool(), g, "Java" );
            g.CodeGenerator = generator;
            if ( g.NumberOfDecisions == 0 )
            {
                g.BuildNFA();
                g.CreateLookaheadDFAs( false );
            }

            DFA dfa = g.GetLookaheadDFA( 1 );
            Assert.AreEqual( null, dfa ); // can't analyze.

            /*
            String expecting =
                ".s0-ID->.s1" + NewLine +
                ".s1-{p1}?->:s2=>1" + NewLine +
                ".s1-{true}?->:s3=>2" + NewLine;
            String result = serializer.serialize(dfa.startState);
            Assert.AreEqual(expecting, result);
            */

            Assert.AreEqual(1, equeue.size(), "unexpected number of expected problems");
            Message msg = equeue.errors[0];
            Assert.IsTrue(msg is LeftRecursionCyclesMessage, "warning must be a left recursion msg");
        }

        //throws Exception
        protected void checkDecision( Grammar g,
                                     int decision,
                                     string expecting,
                                     int[] expectingUnreachableAlts,
                                     int[] expectingNonDetAlts,
                                     string expectingAmbigInput,
                                     int[] expectingDanglingAlts,
                                     int expectingNumWarnings )
        {
            DecisionProbe.verbose = true; // make sure we get all error info
            ErrorQueue equeue = new ErrorQueue();
            ErrorManager.SetErrorListener( equeue );

            // mimic actions of org.antlr.Tool first time for grammar g
            if ( g.NumberOfDecisions == 0 )
            {
                g.BuildNFA();
                g.CreateLookaheadDFAs( false );
            }
            CodeGenerator generator = new CodeGenerator( newTool(), g, "Java" );
            g.CodeGenerator = generator;

            if ( equeue.size() != expectingNumWarnings )
            {
                Console.Error.WriteLine( "Warnings issued: " + equeue );
            }

            Assert.AreEqual(expectingNumWarnings, equeue.size(), "unexpected number of expected problems");

            DFA dfa = g.GetLookaheadDFA( decision );
            Assert.IsNotNull( dfa, "no DFA for decision " + decision );
            FASerializer serializer = new FASerializer( g );
            string result = serializer.Serialize( dfa.StartState );

            var unreachableAlts = dfa.UnreachableAlts;

            // make sure unreachable alts are as expected
            if ( expectingUnreachableAlts != null )
            {
                BitSet s = new BitSet();
                s.AddAll( expectingUnreachableAlts );
                BitSet s2 = new BitSet();
                s2.AddAll( unreachableAlts );
                Assert.AreEqual(s, s2, "unreachable alts mismatch");
            }
            else
            {
                Assert.AreEqual(0, unreachableAlts != null ? unreachableAlts.Count : 0, "number of unreachable alts");
            }

            // check conflicting input
            if ( expectingAmbigInput != null )
            {
                // first, find nondet message
                Message msg = (Message)equeue.warnings[0];
                Assert.IsTrue(msg is GrammarNonDeterminismMessage, "expecting nondeterminism; found " + msg.GetType().Name);
                GrammarNonDeterminismMessage nondetMsg =
                    getNonDeterminismMessage( equeue.warnings );
                var labels =
                    nondetMsg.probe.GetSampleNonDeterministicInputSequence( nondetMsg.problemState );
                string input = nondetMsg.probe.GetInputSequenceDisplay( labels );
                Assert.AreEqual( expectingAmbigInput, input );
            }

            // check nondet alts
            if ( expectingNonDetAlts != null )
            {
                RecursionOverflowMessage recMsg = null;
                GrammarNonDeterminismMessage nondetMsg =
                    getNonDeterminismMessage( equeue.warnings );
                IList<int> nonDetAlts = null;
                if ( nondetMsg != null )
                {
                    nonDetAlts =
                        nondetMsg.probe.GetNonDeterministicAltsForState( nondetMsg.problemState );
                }
                else
                {
                    recMsg = getRecursionOverflowMessage( equeue.warnings );
                    if ( recMsg != null )
                    {
                        //nonDetAlts = new ArrayList(recMsg.alts);
                    }
                }
                // compare nonDetAlts with expectingNonDetAlts
                BitSet s = new BitSet();
                s.AddAll( expectingNonDetAlts );
                BitSet s2 = new BitSet();
                s2.AddAll( nonDetAlts );
                Assert.AreEqual(s, s2, "nondet alts mismatch");
                Assert.IsTrue(nondetMsg != null || recMsg != null, "found no nondet alts; expecting: " + str(expectingNonDetAlts));
            }
            else
            {
                // not expecting any nondet alts, make sure there are none
                GrammarNonDeterminismMessage nondetMsg =
                    getNonDeterminismMessage( equeue.warnings );
                Assert.IsNull(nondetMsg, "found nondet alts, but expecting none");
            }
//.........这里部分代码省略.........

        protected void assertRecursionOverflow( Grammar g,
                                               IList expectedTargetRules,
                                               int expectedAlt )
        {
            DecisionProbe.verbose = true; // make sure we get all error info
            ErrorQueue equeue = new ErrorQueue();
            ErrorManager.SetErrorListener( equeue );

            // mimic actions of org.antlr.Tool first time for grammar g
            if ( g.NumberOfDecisions == 0 )
            {
                g.BuildNFA();
                g.CreateLookaheadDFAs( false );
            }
            RecursionOverflowMessage msg = getRecursionOverflowMessage( equeue.errors );
            Assert.IsNotNull(msg, "missing expected recursion overflow msg" + msg);
            Assert.AreEqual(expectedTargetRules.ToElementString(), msg.targetRules.ToList().ToElementString(), "target rules mismatch");
            Assert.AreEqual(expectedAlt, msg.alt, "mismatched alt");
        }

        protected void assertNonLLStar( Grammar g, IList<int> expectedBadAlts )
        {
            DecisionProbe.verbose = true; // make sure we get all error info
            ErrorQueue equeue = new ErrorQueue();
            ErrorManager.SetErrorListener( equeue );

            // mimic actions of org.antlr.Tool first time for grammar g
            if ( g.NumberOfDecisions == 0 )
            {
                g.BuildNFA();
                g.CreateLookaheadDFAs( false );
            }
            NonRegularDecisionMessage msg = getNonRegularDecisionMessage( equeue.errors );
            Assert.IsNotNull(msg, "expected fatal non-LL(*) msg");
            List<int> alts = new List<int>();
            alts.AddRange( msg.altsWithRecursion );
            alts.Sort();
            //Collections.sort( alts );
            //Assert.AreEqual( expectedBadAlts, alts );
            Assert.IsTrue( expectedBadAlts.SequenceEqual( alts ) );
        }

        public void TestLexerDelegatorRuleOverridesDelegateLeavingNoRules()
        {
            // M.Tokens has nothing to predict tokens from S.  Should
            // not include S.Tokens alt in this case?
            string slave =
                "lexer grammar S;\n" +
                "A : 'a' {System.out.println(\"S.A\");} ;\n";
            mkdir( tmpdir );
            writeFile( tmpdir, "S.g", slave );
            string master =
                "lexer grammar M;\n" +
                "import S;\n" +
                "A : 'a' {System.out.println(\"M.A\");} ;\n" +
                "WS : (' '|'\\n') {skip();} ;\n";
            writeFile( tmpdir, "M.g", master );

            ErrorQueue equeue = new ErrorQueue();
            ErrorManager.SetErrorListener( equeue );
            AntlrTool antlr = newTool( new string[] { "-lib", tmpdir } );
            CompositeGrammar composite = new CompositeGrammar();
            Grammar g = new Grammar( antlr, tmpdir + "/M.g", composite );
            composite.SetDelegationRoot( g );
            g.ParseAndBuildAST();
            composite.AssignTokenTypes();
            composite.DefineGrammarSymbols();
            composite.CreateNFAs();
            g.CreateLookaheadDFAs( false );

            // predict only alts from M not S
            string expectingDFA =
                ".s0-'a'->.s1\n" +
                ".s0-{'\\n', ' '}->:s3=>2\n" +
                ".s1-<EOT>->:s2=>1\n";
            Antlr3.Analysis.DFA dfa = g.GetLookaheadDFA( 1 );
            FASerializer serializer = new FASerializer( g );
            string result = serializer.Serialize( dfa.startState );
            assertEquals( expectingDFA, result );

            // must not be a "unreachable alt: Tokens" error
            assertEquals( "unexpected errors: " + equeue, 0, equeue.errors.Count );
        }