Yes, there are other things like that, that provide error checking on hash keys. There are pseudo-hashes. There's some stuff in Conway's book on OO Perl. There's the use of accessor functions instead of direct hash access. There's Tie::SecureHash mentioned in the 5.8 docs as a replacement for pseudo-hashes for implementing the base/fields modules.

I don't know what does the same kind of type checking you have (as opposed to just allowed keys), but I've read about that kind of thing from time to time.

Perl doesn't require strict typing. In that respect it's more like Smalltalk than C++. That is, an object doesn't necessarily have to be of a particular class (or derived class) to "fit". It just has to have all the right methods available.

---

---

• Are you posting in the right place? Check out Where do I post X? to know for sure.
• Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:

  <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>

• Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
• Want more info? How to link or How to display code and escape characters are good places to start.