Inconsistent grammar

[Fireronin]

On page 30 you have defined
methodProto ::= [ attributeInstances ] method type identifier ( [ methodProtoFormals ] ) ;
but in the example of an interface, you omit empty braces which shouldn't be possible according to the grammar above,

interface IntStack;
  method Action push (int x);
  method Action pop;
  method int top;
endinterface: IntStack

To fix this you could use:
_methodProto ::= [ attributeInstances ] method type identifier ( [ methodProtoFormals ] );
| [ attributeInstances ] method type identifier ;