anchor.diff:  
   nonEmptyStatements
   	:	'^' expression ('.')?
  -	|	expression ('.' statements)?
  +	|	expression ('.' (STATEMENT_INDENT)? statements)?
   	;
   
   expression 
  
positive.code: BINARY_SYMBOL: ('~'|'!'|'@'|'%'|'&'|'*'|'-'|'+'|'='|'\\'|'|'|'?'|'/'|'>'|'<'|',') ('~'|'!'|'@'|'%'|'&'|'*'|'-'|'+'|'='|'\\'|'|'|'?'|'/'|'>'|'<'|',')*;
  CHARACTER: '$' . ;
  COMMENT: '"' .* '"' {$channel = HIDDEN;};
  TAB: '\t';
  WHITESPACE: (' ' | '\n' | '\r' | '\f' )+ {$channel = HIDDEN;};
  
negative.code: 	;
  
  tabbedStatements
    : STATEMENT_INDENT statements
    ;
   
  statements
  