Beefy Boxes and Bandwidth Generously Provided by pair Networks
Perl: the Markov chain saw

Comment on

( #3333=superdoc: print w/ replies, xml ) Need Help??
...because you typed 'use ThisModule;' at the top of your code is the simple answer -- since use'ing occurs at compile-time, then the statement must already occur in your code. You cannot load a module twice, if it has already been loaded with use or require. This also means that you can't have two different versions of the same module loaded at one time either.

if you are talking dynamic inclusion of module at runtime, or in response to user responses etc, then the perl idiom you are looking for is:

if ( $i_need_a_dynamically_loaded_module ) { eval "require Module"; $@ && warn $@; }

if you have a list of modules which could do the job but you don't know what the host has, then either traverse @INC manually (clumsy), or try something like:

my $loaded_mod; foreach my $mod ( qw( Module1 Module2 Module3 ) ) { warn "attempting to load '$mod'"; eval "require $mod"; next if $@; warn "'$mod' loaded successfully"; $loaded_mod = $mod; last; } $loaded_mod or die "Couldn't load anything useful..."; ...


In reply to RE: Module Usage by Anonymous Monk
in thread Module Usage by Lord Rau

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?

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

    How do I use this? | Other CB clients
    Other Users?
    Others scrutinizing the Monastery: (5)
    As of 2015-10-10 14:44 GMT
    Find Nodes?
      Voting Booth?

      Does Humor Belong in Programming?

      Results (257 votes), past polls