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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 grammar 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     42 		// 'member' is obsolete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 
     58 options
     59 {
     60 	language=CSharp3;
     61 }
     62 
     63 @header {
     64 // 'member' is obsolete
     65 #pragma warning disable 612
     66 
     67 using Antlr.Runtime.JavaExtensions;
     68 using HashMap = System.Collections.Generic.Dictionary<object,object>;
     69 using Integer = java.lang.Integer;
     70 }
     71 
     72 @members {
     73 /** Map variable name to Integer object holding value */
     74 HashMap memory = new HashMap();
     75 }
     76 
     77 prog:   stat+ ;
     78 
     79 stat:   expr NEWLINE {JSystem.@out.println($expr.value);}
     80     |   ID '=' expr NEWLINE
     81         {memory.put($ID.text, new Integer($expr.value));}
     82     |   NEWLINE
     83     ;
     84 
     85 expr returns [int value]
     86     :   e=multExpr {$value = $e.value;}
     87         (   '+' e=multExpr {$value += $e.value;}
     88         |   '-' e=multExpr {$value -= $e.value;}
     89         )*
     90     ;
     91 
     92 multExpr returns [int value]
     93     :   e=atom {$value = $e.value;} ('*' e=atom {$value *= $e.value;})*
     94     ;
     95 
     96 atom returns [int value]
     97     :   INT {$value = Integer.parseInt($INT.text);}
     98     |   ID
     99         {
    100         Integer v = (Integer)memory.get($ID.text);
    101         if ( v!=null ) $value = v.intValue();
    102         else JSystem.err.println("undefined variable "+$ID.text);
    103         }
    104     |   '(' expr ')' {$value = $expr.value;}
    105     ;
    106 
    107 ID  :   ('a'..'z'|'A'..'Z')+ ;
    108 INT :   '0'..'9'+ ;
    109 NEWLINE:'\r'? '\n' ;
    110 WS  :   (' '|'\t')+ {Skip();} ;
    111