From 629f67b39cae2277b8eeab58242a4a63a879c1f0 Mon Sep 17 00:00:00 2001
From: nitrix <me@nitrix.one>
Date: Mon, 16 Dec 2019 21:44:37 +0100
Subject: [PATCH] make expressions nestable

---
 .../antlr4/de/hsrm/compiler/Klang/Klang.g4    | 25 +++++++++++--------
 1 file changed, 14 insertions(+), 11 deletions(-)

diff --git a/src/main/antlr4/de/hsrm/compiler/Klang/Klang.g4 b/src/main/antlr4/de/hsrm/compiler/Klang/Klang.g4
index 9263309..a6dbbb7 100644
--- a/src/main/antlr4/de/hsrm/compiler/Klang/Klang.g4
+++ b/src/main/antlr4/de/hsrm/compiler/Klang/Klang.g4
@@ -44,14 +44,21 @@ return_statement
   ;
 
 expression
-  : atom MULT atom #multiplicationExpression
-  | atom op=(ADD | SUB) atom #additiveExpression
-  | atom MOD atom #moduloExpression
-  | SUB atom #unaryNegateExpression
-  | atom #atomExpression
+  : atom #atomExpression
+  | OPAR lhs=expression ADD rhs=expression CPAR #additionExpression
+  | OPAR lhs=expression SUB rhs=expression CPAR #substractionExpression
+  | OPAR lhs=expression MUL rhs=expression CPAR #multiplicationExpression
+  | OPAR lhs=expression DIV rhs=expression CPAR #divisionExpression
+  | OPAR lhs=expression MOD rhs=expression CPAR #moduloExpression
+  | SUB expression #negateExpression
   | functionCall #functionCallExpression
   ;
 
+atom
+  : INTEGER_LITERAL #intAtom
+  | IDENT # variable
+  ;
+
 functionCall
   : IDENT OPAR arguments CPAR
   ;
@@ -60,11 +67,6 @@ arguments
   : (expression (COMMA expression)*)?
   ;
 
-atom
-  : INTEGER_LITERAL #intAtom
-  | IDENT # variable
-  ;
-
 PRINT: 'print';
 IF: 'if';
 ELSE: 'else';
@@ -79,10 +81,11 @@ CPAR: ')';
 COMMA: ',';
 EQUAL: '=';
 
-MULT: '*';
+MUL: '*';
 ADD: '+';
 SUB: '-';
 MOD: '%';
+DIV: '/';
 
 INTEGER_LITERAL
   : [0-9]+