1/*
2 * [The "BSD license"]
3 * Copyright (c) 2011 Terence Parr
4 * All rights reserved.
5 *
6 * Conversion to C#:
7 * Copyright (c) 2011 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
33grammar Expr;
34
35/*
36	I had to make the following changes to the basic Expr grammar to make it work with the CSharp3 target in "Java compatibility mode".
37	For reference, see http://www.antlr.org/wiki/display/ANTLR3/Expression+evaluator.
38
39	Add an options section to set the language to CSharp3.
40
41	In the @header section, add:
42		// 'member' is obsolete
43		#pragma warning disable 612
44		using Antlr.Runtime.JavaExtensions;
45
46	In the @header section, replace:
47			import java.util.HashMap;
48		with:
49			using HashMap = System.Collections.Generic.Dictionary<object,object>;
50
51	Change all instances of "System.out" with "JSystem.@out".
52
53	Change all instances of "System.err" with "JSystem.err".
54
55	Change all instances of "skip()" with "Skip()".
56 */
57
58options
59{
60	language=CSharp3;
61}
62
63@header {
64// 'member' is obsolete
65#pragma warning disable 612
66
67using Antlr.Runtime.JavaExtensions;
68using HashMap = System.Collections.Generic.Dictionary<object,object>;
69using Integer = java.lang.Integer;
70}
71
72@members {
73/** Map variable name to Integer object holding value */
74HashMap memory = new HashMap();
75}
76
77@lexer::namespace{Antlr3.Runtime.Test.JavaCompat}
78@parser::namespace{Antlr3.Runtime.Test.JavaCompat}
79
80prog:   stat+ ;
81
82stat:   expr NEWLINE {JSystem.@out.println($expr.value);}
83    |   ID '=' expr NEWLINE
84        {memory.put($ID.text, new Integer($expr.value));}
85    |   NEWLINE
86    ;
87
88expr returns [int value]
89    :   e=multExpr {$value = $e.value;}
90        (   '+' e=multExpr {$value += $e.value;}
91        |   '-' e=multExpr {$value -= $e.value;}
92        )*
93    ;
94
95multExpr returns [int value]
96    :   e=atom {$value = $e.value;} ('*' e=atom {$value *= $e.value;})*
97    ;
98
99atom returns [int value]
100    :   INT {$value = Integer.parseInt($INT.text);}
101    |   ID
102        {
103        Integer v = (Integer)memory.get($ID.text);
104        if ( v!=null ) $value = v.intValue();
105        else JSystem.err.println("undefined variable "+$ID.text);
106        }
107    |   '(' expr ')' {$value = $expr.value;}
108    ;
109
110ID  :   ('a'..'z'|'A'..'Z')+ ;
111INT :   '0'..'9'+ ;
112NEWLINE:'\r'? '\n' ;
113WS  :   (' '|'\t')+ {Skip();} ;
114