private static function parseReal($value)
    {
        if ($value == '') return null;

        $x = str_replace(',', '.', $value);
        if (static::isSignedReal($x)) return floatval($x);
        else throw new SyntaxErrorException();
    }
private static function parseReal($value)
    {
        if ($value == '') return null;

        $x = str_replace(',', '.', $value);
        if (static::isSignedReal($x)) return floatval($x);
        else throw new SyntaxErrorException();
    }
private static function parseReal ( $ value ) { if ( $ value == '' ) return null ; $ x = str_replace ( ',' , '.' , $ value ) ; if ( static :: isSignedReal ( $ x ) ) return floatval ( $ x ) ; else throw new SyntaxErrorException ( ) ; }
convert string to floating point number, if possible

decimal commas accepted

@param string $value
@throws SyntaxErrorException if the string cannot be parsed
@retval float
convert string to floating point number if possible