[PEPr] Comment on Numbers::ISBN

This proposal looks to have some nice code in it. Are you going to finish it up? Some quick suggestions if you do: 1.) use class constants instead of global defines 2.) put exceptions in a separate file 3.) variable names should use camelCase, not under_scores. 4.) give it a run through phpcs. It will pick up many minor problems with spacing and doc formatting. 5.) if you're passing parameters by reference, you'd better document it well! 6.) private static methods will be hard to write tests for. You may want to ask on the PHPUnit mailing list for guidance here. 7.) Regarding Ken's comment, the existence of Validate_ISPN is not a reason to discontinue development of this package. If anything, Validate_ISPN could just depend on this package if it gets accepted. This proposal seems to cover more aspects of ISBN than just validating. -- http://pear.php.net/pepr/pepr-proposal-show.php?id=469