# Generates a list of [doc://*] tags from current 
# Perl function index for further verification.

use strict;
use warnings;
use LWP::Simple;

my $perlfunc_index_url = 'http://perldoc.perl.org/index-functions.html
+';
my $content            =    get( $perlfunc_index_url )
                         or die "Cannot get $perlfunc_index_url - $!";

foreach (split /\n/, $content ) {
  print "[doc://$1]\n" if m{href="functions/.*?">([^<]+)}; # I know...
}

__END__
[doc://abs]
[doc://accept]
[doc://alarm]
[doc://atan2]
[doc://bind]
...
[doc://-X]
[doc://y]
[download]

... generates a list that PM expands to (broken tags highlighted manually):
abs accept alarm atan2 bind binmode bless break caller chdir chmod chomp chop chown chr chroot close closedir connect continue cos crypt dbmclose dbmopen default defined delete die do dump each endgrent endhostent endnetent endprotoent endpwent endservent eof eval exec exists exit exp fcntl fileno flock fork format formline getc getgrent getgrgid getgrnam gethostbyaddr gethostbyname gethostent getlogin getnetbyaddr getnetbyname getnetent getpeername getpgrp getppid getpriority getprotobyname getprotobynumber getprotoent getpwent getpwnam getpwuid getservbyname getservbyport getservent getsockname getsockopt given glob gmtime goto grep hex import index int ioctl join keys kill last lc lcfirst length link listen local localtime lock log lstat m map mkdir msgctl msgget msgrcv msgsnd my next no oct open opendir ord our pack package pipe pop pos print printf prototype push q qq qr quotemeta qw qx rand read readdir readline readlink readpipe recv redo ref rename require reset return reverse rewinddir rindex rmdir s say scalar seek seekdir select semctl semget semop send setgrent sethostent setnetent setpgrp setpriority setprotoent setpwent setservent setsockopt shift shmctl shmget shmread shmwrite shutdown sin sleep socket socketpair sort splice split sprintf sqrt srand stat state study sub substr symlink syscall sysopen sysread sysseek system syswrite tell telldir tie tied time times tr truncate uc ucfirst umask undef unlink unpack unshift untie use utime values vec wait waitpid wantarray warn when write -X y