Beefy Boxes and Bandwidth Generously Provided by pair Networks
Syntactic Confectionery Delight
 
PerlMonks  

Comment on

( #3333=superdoc: print w/ replies, xml ) Need Help??
eval " use $breed; " ;

Also, in true merlyn fashion, it looks like eval in this string context makes you have unsafe doggies if you are using your dogs on a web site and allowing input of the doggie type in a text field.

$dog = ' strict; doEvil(); ';

I also think the strange use of dog as a factory class to produce subtypes of dogs is a little odd-form from an OO form, and that most OO purists would frown on the eval and use of reflection to pick subclasses. But I come from a very non-Perlish OO background, so this is just my two cents.

In conclusion, if we want to call this a tutorial, I say this should be a tutorial on the factory pattern, not a tutorial on polymorphism. Polymorphism is a much more general concept, and we skip over that generality by starting with the factory piece first. I would be interested to see if the factory could be made without using eval, as well...I think it can, especially if the dogs were loaded previously in a more-safe matter. But hey, maybe we don't have to worry about unsafe loading of doggies -- they do allright in the back of a pickup truck usually :)

Anyway, cool stuff, just a few ideas thrown out here. *yelp*.


In reply to Re: •Re: It's a dog, but what kind? (polymorphism , in Perl OO) by flyingmoose
in thread It's a dog, but what kind? (polymorphism , in Perl OO) by blue_cowdawg

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":



  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.
  • Log In?
    Username:
    Password:

    What's my password?
    Create A New User
    Chatterbox?
    and the web crawler heard nothing...

    How do I use this? | Other CB clients
    Other Users?
    Others rifling through the Monastery: (16)
    As of 2015-07-28 15:08 GMT
    Sections?
    Information?
    Find Nodes?
    Leftovers?
      Voting Booth?

      The top three priorities of my open tasks are (in descending order of likelihood to be worked on) ...









      Results (257 votes), past polls