anchor.diff:  
   options {  
     output=AST; 
  -}  
  +  ASTLabelType=CommonTree;
  +}
   
   tokens {
   	STATEMENTS;
  
positive.code: 
  arithm_variable
  	:	arithm_constant
  	|	(NEGATIVE)? BRACKET_OPEN arithm_constant BRACKET_CLOSE -> ^(NEGATIVE? arithm_constant)
  	;
  
  expr	:	addition;
  
negative.code: /*
  	PARSER RULES
  */
  idDeclaration[Token type]
  	:	ID -> ^(DECLARATION {type} ID);
      
  declaration
  	:	t=TYPE decs+=idDeclaration[$t] (LIST_SEPARATOR decs+=idDeclaration[$t])* STATEMENT_END NL? -> $decs*;
  	
  declarations
  	:	(declaration)* -> ^(DECLARATIONS declaration*);
  	
  
  print	:	PRINT_KEY BRACKET_OPEN (
  			STRING -> ^(FUNCTION ^(PRINT_KEY STRING))
  