From fcecd0e7dc0bf103986c02e2f29fb518cd5571c5 Mon Sep 17 00:00:00 2001
From: Carlo Zancanaro <carlo@carlo-laptop>
Date: Thu, 3 May 2012 15:35:39 +1000
Subject: Add a parser for linear equations

(Also add the antlr jar and C runtime)
---
 impl/EquationSystem.g | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100644 impl/EquationSystem.g

(limited to 'impl/EquationSystem.g')

diff --git a/impl/EquationSystem.g b/impl/EquationSystem.g
new file mode 100644
index 0000000..d7e55a7
--- /dev/null
+++ b/impl/EquationSystem.g
@@ -0,0 +1,39 @@
+grammar EquationSystem;
+
+options {
+  language=C;
+  output=AST;
+}
+
+tokens {
+  SYSTEM = 'system' ;
+  PLUS = '+' ;
+  SUB = '-' ;
+  MULT = '*' ;
+  MAXIMUM = 'max' ;
+  MINIMUM = 'min' ;
+  NEWLINE = '\n' ;
+}
+
+equation_system : equation ( NEWLINE! + equation  )* (NEWLINE!) *;
+equation : VARIABLE '='! maxExpr;
+
+maxExpr : MAXIMUM^ '('! minExpr ( ','! minExpr )* ')'! | minExpr;
+minExpr : MINIMUM^ '('! maxExpr ( ','! maxExpr )* ')'! | expr ;
+
+expr : term ( (PLUS | MULT | SUB)^ term )* ;
+
+term : NUMBER | VARIABLE ;
+
+
+NUMBER : (DIGIT)+ ;
+VARIABLE: (LETTER)+ ;
+WHITESPACE : ( '\t' | ' ' | '\u000C' )+
+             {
+               $channel = HIDDEN;
+             } ;
+
+fragment
+DIGIT : '0' .. '9' ;
+fragment
+LETTER: 'a' .. 'z' ;
-- 
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