diff --git a/data/Example3.circom b/data/Example3.circom
index 509389b..a1bc4d0 100644
--- a/data/Example3.circom
+++ b/data/Example3.circom
@@ -1,4 +1,4 @@
-bus B1(){
+bus B1 {
     signal x;
 }
 
diff --git a/grammar/CircomParser.g4 b/grammar/CircomParser.g4
index 77aa0e5..05644fe 100644
--- a/grammar/CircomParser.g4
+++ b/grammar/CircomParser.g4
@@ -44,10 +44,10 @@ blockDefiniton
 functionDefinition: 'function' ID '(' argNames=simpleIdentifierList? ')' body ;
 
 templateDefinition
-    : 'template' 'custom'? 'parallel'? ID '(' argNames=simpleIdentifierList? ')' body
+    : 'template' 'custom'? 'parallel'? ID ('(' argNames=simpleIdentifierList? ')')? body
     ;
 
-busDefinition: 'bus' ID '(' argNames=simpleIdentifierList? ')' body ;
+busDefinition: 'bus' ID ('(' argNames=simpleIdentifierList? ')')? body ;
 
 publicInputsDefinition: '{' 'public' '[' publicInputs=simpleIdentifierList ']' '}' ;