function get_rules( $nt ){
		$rules = array();
		if( isset($this->ntindex[$nt]) ){
			foreach( $this->ntindex[$nt] as $i ){
				$rules[$i] = $this->rules[$i]; 
			}
		} 
		return $rules;
	}
function get_rules( $nt ){
		$rules = array();
		if( isset($this->ntindex[$nt]) ){
			foreach( $this->ntindex[$nt] as $i ){
				$rules[$i] = $this->rules[$i]; 
			}
		} 
		return $rules;
	}
function get_rules ( $ nt ) { $ rules = array ( ) ; if ( isset ( $ this -> ntindex [ $ nt ] ) ) { foreach ( $ this -> ntindex [ $ nt ] as $ i ) { $ rules [ $ i ] = $ this -> rules [ $ i ] ; } } return $ rules ; }
Get rules by non-terminal left hand side
@param int|string non terminal symbol
@return array none or more rule arrays
Get rules by non - terminal left hand side