Another possibility is to simply require the modules you need and let them define subroutines and such. For example, in the program from which my simple command parser comes from, the commands are loaded from a directory in which files with names starting with 2 digist and ending with ".pl" are assumed to define the appropriate subroutines and variables. Here's a simplified version of what I use to load them. Notice how I also incorporate variables declared in each module (in this case %COMMAND) into another global hash.

  # Load command modules
  if (-d $cmddir) {
    opendir(CMDDIR, $cmddir)
      or die "Error opening '$cmddir': $!\n";
    # Get only .pl files that start with 2 digits and that contain onl
+y
    # alphanumerics, underscores, hyphens or dots in their names.
    my @cmdfiles=map { (/^(\d{2}[-\w.]+\.pl)$/ && $1) || () } readdir(
+CMDDIR);
    closedir(CMDDIR);
    # Read each file and incorporate its %COMMANDS into %ALLCOMMANDS
    my $cmdfile;
    if (@cmdfiles) {
      foreach $cmdfile (@cmdfiles) {
        local %COMMANDS;
        eval "require '$cmddir/$cmdfile'";
        die "Error loading '$cmddir/$cmdfile': $!\n" if $@;
        my ($k,$v);
        # Incorporate commands
        while (($k,$v)=each(%COMMANDS)) {
          $ALLCOMMANDS{$k}=$v;
        }
      }
    }
    else {
      # Print warning, but continue, because builtin commands can stil
+l
      # be used (not very useful, but...)
      warn "Warning: No command files found in directory '$cmddir'\n";
    }
  } else {
    die "Fatal: Could not find commands dir '$cmddir'\n";
  }
[download]