Beefy Boxes and Bandwidth Generously Provided by pair Networks
Perl-Sensitive Sunglasses
 
PerlMonks  

Comment on

( #3333=superdoc: print w/ replies, xml ) Need Help??
You're asking for symbolic references, huh? At least, I think you are. Well: don't do it, unless you know really well what you're doing — and basically, if you have to ask how to do it, I dare to bet that you don't. Making a name based on a user's input is always very dangerous. You never know whether he'll input the name of a variable you've used yourself in your program.

See dominus' classic 3 articles on his website, for more arguments against it:

  1. Why it's stupid to `use a variable as a variable name'
  2. A More Direct Explanation of the Problem
  3. What if I'm Really Careful?

In general: don't do it. Use a hash. Like this:

my %v; # my hash for user variables $v{Sam}++; # or: my $name = 'Sam'; $v{$name}++;

Oh, and if you really want to do it, try $$name or ${$name}, which both do the same thing, and only work on global (= package) variables — and only with no strict 'refs'. Just to show you it can be done... ;-)

If all you want is to work on predefined variables with no input from the user/outside world, try hard references instead.

my $var = \$sam; $$var++; # increments $sam
Yes, the syntax is exactly the same. That's one reason why coding without strict 'refs' in place, is a rather bad idea.

In reply to Re: variable with $$ by bart
in thread variable with $$ by Anonymous Monk

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 making s'mores by the fire in the courtyard of the Monastery: (7)
    As of 2014-07-30 05:44 GMT
    Sections?
    Information?
    Find Nodes?
    Leftovers?
      Voting Booth?

      My favorite superfluous repetitious redundant duplicative phrase is:









      Results (229 votes), past polls