I think the essential point about attributes is to DRY when marking subs and variables.

so this code might be explicit but repeats the subname hello as a string.

around 'hello' => \&makebold;

Please note that attributes are not necessarily wrapping code.

One use-case for instance could be to set a breakpoint for the debugger

sub tst :break {
  ...
}

[download]

Another to restrict the type to variables

my $y :Int;

[download]

which might be very helpful when trying to translate Perl code to a typed language like C.

All use cases could be achieved by adding tst or $y to a hash somewhere, but the possibility to do it right at the point of interest w/o name repetition can be very handy and avoids headaches when refactoring.

Just imagine the overhead for a refactoring tool to find all hellos after sub hello was renamed.

Cheers Rolf

( addicted to the Perl Programming Language)

update

I'm no expert of Moose's compile phases, but a DRY notation of around using attributes would look like

sub hello :around(makebold) {

  return "ohai";

}

[download]

In reply to Re^2: RFC: Simulating Python's @decorators in Perl with Attributes by LanX
in thread RFC: Simulating Python's @decorators in Perl with Attributes by LanX

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.