Class Module {
  val Type[*] types;
  val VariableDeclaration[*] variables;
  val Element[*] elements;
  val Connection[*] connexions;
}

Class Type {
  attr String[1] name;
}

Class VariableDeclaration {
  attr String[1] name;
  ref Type[1] type;
}

Class Element {
  attr String[1] name;
}

Class Connection {
  ref Element[1] from;
  ref Element[1] to;
}

Module:
  Types type1, type2;
  Variables
    x, y : type1;
    z : type2;
  Elements
    element1 connectsTo element2, element3;
    element2 connectsTo element3;
    element3;

Module returns Module:
'Types' '{'
(types+=Type)+
'}'
'Variables' '{' 
((variables+=UnSortedVariableDeclaration ',')* variables+=SortedVariableDeclaration ';')+ 
'}';

Type returns Type:
  name=ID;

SortedVariableDeclaration returns VariableDeclaration:
  name=ID ':' type=[Type];

UnSortedVariableDeclaration returns VariableDeclaration:
  name=ID;