Really? I think most either don't know or prefer avoiding code_refs.

It's a very special magic which is practically not mentioned in the docs and never in conjunction with the word "private".

I grepped thru all pods for ->$ and found only 10 occurences from which 8 are only of the string form ->$methname and only 2 with ->$coderef:

/usr/share/perl/5.10/pod/perlbot.pod:           $self->{'delegate'}->$
+AUTOLOAD(@_);
/usr/share/perl/5.10/pod/perlfaq7.pod:                  $widget->$tric
+k();
/usr/share/perl/5.10/pod/perlsec.pod:    $obj->$method(@args);
/usr/share/perl/5.10/pod/perltooc.pod:      $self->$methname($newvalue
+);
/usr/share/perl/5.10/pod/perltooc.pod:      $self->$coderef($newvalue)
+;
/usr/share/perl/5.10/pod/perltoot.pod:                return ref_to($c
+lass->$methname);
/usr/share/perl/5.10/pod/perltoot.pod:                return ref_to($c
+lass->$methname);
/usr/share/perl/5.10/pod/perlunicode.pod:      return $sth->$what;
/usr/share/perl/5.10/pod/perlunicode.pod:        my @arr = $sth->$what
+;
/usr/share/perl/5.10/pod/perlunicode.pod:        my $ret = $sth->$what
+;
[download]

the only explanation I found was in perlop

The Arrow Operator

""->"" is an infix dereference operator, just as it is in C and C++. If the right side is either a "...", "{...}", or a "(...)" subscript, then the left side must be either a hard or symbolic reference to an array, a hash, or a subroutine respectively. (Or technically speaking, a location capable of holding a hard reference, if it’s an array or hash reference being used for assignment.) See perlreftut and perlref.

Otherwise, the right side is a method name or a simple scalar variable containing either the method name or a subroutine reference, and the left side must be either an object (a blessed reference) or a class name (that is, a package name). See perlobj.