The ampersand & marks the following { } construct as a code block; the backslash disambiguates that operation from binary '&' (the bitwise AND) and returns a reference for that code block.

It's not really a code block. \&{foo} is a reference to the subroutine with the name "foo". Similarly, \& { print "foo" } is a reference to the subroutine with the name that is returned by print, i. e. it's \&1 (unless print fails). 

$ perl -lwe 'my $code = \&{print "foo"}'
foo
$ perl -lwe 'my $code = \&{print "foo"}; $code->()'
foo
Undefined subroutine &main::1 called at -e line 1.

[download]

(Note that $code is not called/dereferenced in the first one-liner, yet it prints foo.

In reply to Re^2: Mr. Ternary is greater than Mrs. If Else by betterworld
in thread Mr. Ternary is greater than Mrs. If Else by PerlPhi

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.