From ea05c9c5fa30b8822f618e861d12a09df1f8f017 Mon Sep 17 00:00:00 2001
From: Carlo Zancanaro <carlo@carlo-laptop>
Date: Mon, 28 May 2012 13:00:50 +1000
Subject: Fix memory error and x = max(-inf, expr) stuff.

---
 impl/EquationSystem.g | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

(limited to 'impl/EquationSystem.g')

diff --git a/impl/EquationSystem.g b/impl/EquationSystem.g
index 6db7045..3a6598a 100644
--- a/impl/EquationSystem.g
+++ b/impl/EquationSystem.g
@@ -3,27 +3,34 @@ grammar EquationSystem;
 options {
   language=C;
   output=AST;
+  backtrack=true;
 }
 
 tokens {
-  SYSTEM = 'system' ;
   PLUS = '+' ;
   SUB = '-' ;
   MULT = '*' ;
+  COMMA = ';' ;
+  GUARD = 'guard' ;
+  GREATER_EQUAL = '>=' ;
+  QUESTION_MARK = '?' ;
   MAXIMUM = 'max' ;
   MINIMUM = 'min' ;
   NEWLINE = '\n' ;
 }
 
-equation_system : equation ( NEWLINE! + equation  )* (NEWLINE!) *;
-equation : VARIABLE '='! maxExpr;
+equation_system : equation ( NEWLINE! + equation  )* (NEWLINE!)* ;
+equation : VARIABLE '='! maxExpr ;
 
-maxExpr : MAXIMUM^ '('! minExpr ( ','! minExpr )* ')'! | minExpr;
+maxExpr : MAXIMUM^ '('! minExpr ( ','! minExpr )* ')'! | minExpr ;
 minExpr : MINIMUM^ '('! maxExpr ( ','! maxExpr )* ')'! | expr ;
 
-expr : term ( (PLUS | MULT | SUB)^ term )* ;
+expr : '(' expr GREATER_EQUAL expr QUESTION_MARK expr ')' -> ^(GUARD expr expr expr)
+     | term ( (PLUS | MULT | SUB | COMMA)^ expr )* ;
 
-term : NUMBER | VARIABLE ;
+term : NUMBER
+     | VARIABLE
+     | '('! expr ')'! ;
 
 
 NUMBER : (DIGIT)+ ;
-- 
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