I couldn't understand the purpose of the bless function

Normally, if you have a hash reference:

my $hash = {
     a => 1,
     b => 2
};

[download]

you can write:

say $hash->{a};

[download]

but you cannot use a hash reference to call a function, e.g.

$hash->some_func()

[download]

If you look at the code that creates a class, the new() function creates a variable called $self and assigns it a reference to a hash. bless() makes it so that you can use the hash reference to call functions.

An object is different from any other data type in Perl in one and only one way: you may dereference it using not merely string or numeric subscripts with simple arrays and hashes...

$aref->[0]
$href->{'a'}

...but with named subroutine calls...

$href->some_func()

In a word, with methods.

perltoot

In reply to Re^3: How to detect a hash container key from a referenced sub value by 7stud
in thread How to detect a hash container key from a referenced sub value by igoryonya

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!
  • 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, details, 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, summary, 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.