Tracer.cs revision 324c4644fee44b9898524c09511bd33c3f12e2df 
1/*
2 * [The "BSD licence"]
3 * Copyright (c) 2005-2008 Terence Parr
4 * All rights reserved.
5 *
6 * Conversion to C#:
7 * Copyright (c) 2008-2009 Sam Harwell, Pixel Mine, Inc.
8 * All rights reserved.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 * 3. The name of the author may not be used to endorse or promote products
19 *    derived from this software without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
24 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
26 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
30 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31 */
32
33namespace Antlr.Runtime.Debug
34{
35    using Antlr.Runtime.JavaExtensions;
36
37    using Console = System.Console;
38
39    /** <summary>
40     *  The default tracer mimics the traceParser behavior of ANTLR 2.x.
41     *  This listens for debugging events from the parser and implies
42     *  that you cannot debug and trace at the same time.
43     *  </summary>
44     */
45    public class Tracer : BlankDebugEventListener
46    {
47        public IIntStream input;
48        protected int level = 0;
49
50        public Tracer( IIntStream input )
51        {
52            this.input = input;
53        }
54
55        public virtual void EnterRule( string ruleName )
56        {
57            for ( int i = 1; i <= level; i++ )
58            {
59                Console.Out.Write( " " );
60            }
61            Console.Out.WriteLine( "> " + ruleName + " lookahead(1)=" + GetInputSymbol( 1 ) );
62            level++;
63        }
64
65        public virtual void ExitRule( string ruleName )
66        {
67            level--;
68            for ( int i = 1; i <= level; i++ )
69            {
70                Console.Out.Write( " " );
71            }
72            Console.Out.WriteLine( "< " + ruleName + " lookahead(1)=" + GetInputSymbol( 1 ) );
73        }
74
75        public virtual object GetInputSymbol( int k )
76        {
77            if ( input is ITokenStream )
78            {
79                return ( (ITokenStream)input ).LT( k );
80            }
81            return (char)input.LA( k );
82        }
83    }
84}
85
86