anchor.diff:  
   // if, elif, else, for, end
   controlStmt
  -    :   ifStmt (elifStmt)* (elseStmt)? endIfStmt    # ifCtrlStmt
  -    |   forStmt endForStmt                          # forCtrlStmt
  +    :   ifStmt (elifStmt)* (elseStmt)? endStmt  # ifCtrlStmt
  +    |   forStmt endStmt                         # forCtrlStmt
       ;
   
   ifStmt
  
positive.code:     :   '<<' 'else' '>>' block*
      ;
  
  endIfStmt
      :   '<<' 'end' '>>'
      ;
  
  
negative.code:     :   '<<' 'for' wsa variable 'in' expr '>>' NL? block*
      //|   '<<' 'for' wsa key=variable ',' val=variable 'in' expr '>>' NL? block*
      |   '<<' 'for' wsa variable 'in' interval '>>' NL? block*
      ;
  
  expr
  