About the way CGI::Cookie parses cookie

sub parse {
  my ($self,$raw_cookie) = @_;
  my %results;

  my @pairs = split("[;,] ?",$raw_cookie);
  foreach (@pairs) {
    s/\s*(.*?)\s*/$1/;
    my($key,$value) = split("=",$_,2);

    # Some foreign cookies are not in name=value format, so ignore
    # them.
    next if !defined($value);
    my @values = ();
    if ($value ne '') {
      @values = map unescape($_),split(/[&;]/,$value.'&dmy');
      pop @values;
    }
    $key = unescape($key);
    # A bug in Netscape can cause several cookies with same name to
    # appear.  The FIRST one in HTTP_COOKIE is the most recent version.
    $results{$key} ||= $self-&g开发者_开发技巧t;new(-name=>$key,-value=>\@values);
  }
  return \%results unless wantarray;
  return %results;
}

Anyone knows why @values = map unescape($_),split(/[&;]/,$value.'&dmy'); is there?

Why must convert it to an array first?

Converted? First? Your question doesn't make much sense. I'm going to assume you want to know what the code that populates @values does.

The code in question takes a string containing a series of values, and separates it into a list of values. This list is stored in an array because it's the only type of variable that would hold that.

I'm not clear on why &dmy is added and then removed. I suspect it's to prevent empty trailing arguments from being removed by split, but a third argument of -1 would do that more clearly.

A cookie can have multiple fields, and each field can have multiple values. The delimiters used are either semi-colons and ampersands:

time=12345678; items=123&456&789; other=abc

or alternatively commas and semicolons:

time=12345678, items=123;456;789, other=abc

Note that in the second case a space may not follow the semi-colon - otherwise it will be interpreted as field assignment delimiter.

So, to answer your question, it converts to an array because a cookie field can have multiple values.