In Exporter.pm, 
  if ($Verbose or $Debug 
      or grep {/\W/ or $args and not exists $exports{$_}
           or @fail and $_ eq $fail[0]
           or (@{"$pkg\::EXPORT_OK"} 
           and $_ eq ${"$pkg\::EXPORT_OK"}[0])} @_) {
    return export $pkg, $callpkg, ($args ? @_ : ());
  }
  #local $SIG{__WARN__} = sub {require Carp; goto &Carp::carp};
  local $SIG{__WARN__} = 
    sub {require Carp; local $Carp::CarpLevel = 1; &Carp::carp};
  foreach $sym (@_) {
    # shortcut for the common case of no type character
    *{"$callpkg\::$sym"} = \&{"$pkg\::$sym"};
  }

[download]
It appears that the concept is to call export in the general case, and do an inline symbol assignment if all special conditions are met.

But just what does that condition say? I understand setting $Verbose or $Debug, and see that the rest is inside a grep to test each argument against some conditions.

But, what is the significance of the first element of @EXPORT_OK or the first element of @fail? Basically, if one of the arguments is the first entry in @EXPORT_OK, then the general case is performed.

So what's special about the first OK item?

—John

In reply to What does this code do? by John M. Dlugosz

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.