Beefy Boxes and Bandwidth Generously Provided by pair Networks
Pathologically Eclectic Rubbish Lister

Comment on

( #3333=superdoc: print w/ replies, xml ) Need Help??
> am I correct in thinking that this is using the or operator as you would like += or .=

almost, you are describing ||= which assigns if the left side is false. you can find this combination in many languages.

But current Perl versions also have // for defined-or, which only act on undef and not other false values.

so $type //= "SCALAR" means $type = defined $type ? $type : "SCALAR";

> performs the operation on $_[0]. Currently I'm trying to become more comfortable with references (and they're very confusing)

It's even more confusing, cause it's not a reference but an alias. Changing elements of @_ means directly changing the passed arguments (see perlsub).

Ironically references shouldn't be confusing, because in most languages arrays and hashes are always copied as references and automatically dereferenced. Perl is one of the rare languages which make a distinction between two flavours.

In JS for instance something like a=[];b=a; a[1]=42; b[1] == 42 is true, because a and b are references to the same array.

In Perl you need to explicitly copy references to achieve this, since @b=@a only copies the elements.

But alternatively you can do like JS does with references:

$a=[]; $b=$a; $a->[1]=42; $b->[1] == 42

Cheers Rolf

( addicted to the Perl Programming Language)

In reply to Re^4: Manipulate deepest values in complex hash structures by LanX
in thread Manipulate deepest values in complex hash structures by RecursionBane

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!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • 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 wandering the Monastery: (10)
    As of 2015-11-25 15:04 GMT
    Find Nodes?
      Voting Booth?

      What would be the most significant thing to happen if a rope (or wire) tied the Earth and the Moon together?

      Results (679 votes), past polls