Beefy Boxes and Bandwidth Generously Provided by pair Networks
P is for Practical
 
PerlMonks  

Comment on

( #3333=superdoc: print w/ replies, xml ) Need Help??

First, neither of those are closures. They are both examples of static variables and named functions. The term "closure" refers to a code reference that also carries along some variables. In neither of these case is the $x being carried around in a code reference (in part because no code references are being used).

Second, I (if anyone cares) don't consider my $x if 0; to be a good thing to actually use. A while back I had an idea to allow BEGIN to be a statement modifier just like for, while, if, etc. Then you could implement static variables like:

sub foo { my $x= 'a' BEGIN; return ++$x; }
which has the benefit of allowing you to initialize your static vars and of cluing you into the fact that the initialization happens at compile time so you can't use anything that isn't available yet.

This feature would have other nifty uses. For example: my $haveCGI= eval { require CGI }   BEGIN;
But the one that could be really fun would be: eval "my $ARGV[0];"   BEGIN;
if you could stop eval from implying an enclosing scope. This could be very powerful and give TheDamian lots of new ways to do really scary things in Perl. (:

        - tye (but my friends call me "Tye")

In reply to (tye)Re: Unusual Closure Behaviour by tye
in thread Unusual Closure Behaviour by tachyon

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
  • Outside of code tags, you may need to use entities for some characters:
            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 contemplating the Monastery: (4)
    As of 2014-12-28 14:33 GMT
    Sections?
    Information?
    Find Nodes?
    Leftovers?
      Voting Booth?

      Is guessing a good strategy for surviving in the IT business?





      Results (181 votes), past polls