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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 
33 namespace 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 
Tracer( IIntStream input )50         public Tracer( IIntStream input )
51         {
52             this.input = input;
53         }
54 
EnterRule( string ruleName )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 
ExitRule( string ruleName )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 
GetInputSymbol( int k )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