| /* |
| * [The "BSD licence"] |
| * Copyright (c) 2005-2008 Terence Parr |
| * All rights reserved. |
| * |
| * Conversion to C#: |
| * Copyright (c) 2008-2009 Sam Harwell, Pixel Mine, Inc. |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * 3. The name of the author may not be used to endorse or promote products |
| * derived from this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| grammar Expr; |
| |
| /* |
| I had to make the following changes to the basic Expr grammar to make it work with the CSharp3 target in "Java compatibility mode". |
| For reference, see http://www.antlr.org/wiki/display/ANTLR3/Expression+evaluator. |
| |
| Add an options section to set the language to CSharp3. |
| |
| In the @header section, add: |
| // 'member' is obsolete |
| #pragma warning disable 612 |
| using Antlr.Runtime.JavaExtensions; |
| |
| In the @header section, replace: |
| import java.util.HashMap; |
| with: |
| using HashMap = System.Collections.Generic.Dictionary<object,object>; |
| |
| Change all instances of "System.out" with "JSystem.@out". |
| |
| Change all instances of "System.err" with "JSystem.err". |
| |
| Change all instances of "skip()" with "Skip()". |
| */ |
| |
| options |
| { |
| language=CSharp3; |
| } |
| |
| @header { |
| // 'member' is obsolete |
| #pragma warning disable 612 |
| |
| using Antlr.Runtime.JavaExtensions; |
| using HashMap = System.Collections.Generic.Dictionary<object,object>; |
| using Integer = java.lang.Integer; |
| } |
| |
| @members { |
| /** Map variable name to Integer object holding value */ |
| HashMap memory = new HashMap(); |
| } |
| |
| prog: stat+ ; |
| |
| stat: expr NEWLINE {JSystem.@out.println($expr.value);} |
| | ID '=' expr NEWLINE |
| {memory.put($ID.text, new Integer($expr.value));} |
| | NEWLINE |
| ; |
| |
| expr returns [int value] |
| : e=multExpr {$value = $e.value;} |
| ( '+' e=multExpr {$value += $e.value;} |
| | '-' e=multExpr {$value -= $e.value;} |
| )* |
| ; |
| |
| multExpr returns [int value] |
| : e=atom {$value = $e.value;} ('*' e=atom {$value *= $e.value;})* |
| ; |
| |
| atom returns [int value] |
| : INT {$value = Integer.parseInt($INT.text);} |
| | ID |
| { |
| Integer v = (Integer)memory.get($ID.text); |
| if ( v!=null ) $value = v.intValue(); |
| else JSystem.err.println("undefined variable "+$ID.text); |
| } |
| | '(' expr ')' {$value = $expr.value;} |
| ; |
| |
| ID : ('a'..'z'|'A'..'Z')+ ; |
| INT : '0'..'9'+ ; |
| NEWLINE:'\r'? '\n' ; |
| WS : (' '|'\t')+ {Skip();} ; |