Beefy Boxes and Bandwidth Generously Provided by pair Networks
Think about Loose Coupling

Comment on

( #3333=superdoc: print w/ replies, xml ) Need Help??
You are 80% right, but it means more than $, you should also include @, %, &.

That is actually sort of comment for a person who is familiar with c/c++. In c/c++, there is a single de-ref operator *. It doesn't matter what the pointer points to, you can always use * to de-ref it.

However in Perl, we do not have such a single operator for de-ref. We have to use @, %, &. There is a big difference. In Perl, in order to de-ref a ref, you have to first know what the ref refs to. In c/c++, type doesn't matter at all, you can always cast a pointer to a certain type, which may have nothing to do with the original type, and then de-ref it, as long as don't corrupt the memory boundary. (In real life, you almost always deref a pointer to something meaningful in the context)
In Perl, if you do:
%a = (1,1,2,2); $a = \%a; print $$a;
It gives you an error, and says that $a is not a SCALAR ref. You have to do:
%a = (1,1,2,2); $a = \%a; print %{$a};
In c/c++, * also de-ref's pointers to functions, in Perl, we have to use &:
sub a { print "abc"; } $a = \&a; &{$a}; # call a, and prints abc

In reply to Re: Dereferencing and comment from Camel by pg
in thread Dereferencing and comment from Camel by jerrygarciuh

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 making s'mores by the fire in the courtyard of the Monastery: (6)
    As of 2015-11-30 06:51 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 (762 votes), past polls