anchor.diff:  fragment SCI_EXP : ('e' | 'E') ('+' | '-')? DIGIT+;
   fragment FP_NUMBER : (DIGIT+ '.' DIGIT*) | ('.' DIGIT+) SCI_EXP;
   NUMBER : (HEX_NUMBER | FP_NUMBER) ('i' | 'I' | 'j' | 'J')?;
  - 
  -//TODO-AC: handle transpose properly
  -fragment STRING_CHAR : ~('\'' | '\r' | '\n') | '\'\'';
  -STRING : '\'' STRING_CHAR* '\'';
   
   PLUS : '+';
   MINUS : '-';
  
positive.code: 
  @lexer::header {
  package matlab;
  }
  
  array :
  
negative.code: ELDIV : '.\\';
  MPOW : '^';
  EPOW : '.^';
  MTRANSPOSE : {isPreTransposeChar(LA(-1))}? '\'';
  ARRAYTRANSPOSE : '.\'';
  LE : '<=';
  GE : '>=';
  