#!/usr/bin/perl -wT
#-*-cperl-*-

use strict;

my (
    $laststate,
    $state,
    $nextstate
   );

open(SOURCE, "< $ARGV[0]")
  or die "Couldn't open $ARGV[0] for reading: $!\n";

# There are three possible line beginnings (ignoring whitespace): '(', ':', and ')'
# There are three possible line endings (ignoring whitespace): '(', ')', and neither one

while (<SOURCE>) {
 SWITCH: {
    # the first line in the file always starts with '('
    # no other line will match this
    /^\(/       && do {
      $state = $laststate = 0;
      $nextstate = 1; # elevate the state
      last SWITCH;
    };
    # lines beginning with ':' always have whitespace before it
    # these lines either maintain or elevate the state, never lower the state
    /^\s+:/ && do {
      $laststate = $state;
      $state = $nextstate;
      # here is where we analyse the line endings
    STATE: {
        # if the line ends with '(', elevate the state
        /\($/ && do {
          $nextstate++;
          last STATE;
        };
        # if the line ends with ')', maintain the state?
        /\)$/ && do {
          last STATE;
        };
        # other line endings elevate the state
        $nextstate++;
      }
      last SWITCH;
    };
    # if the line contains only whitespace and ')', lower the state
     /^\s+\)$/ && do {
       $laststate = $state;
       $state--;
       $nextstate--;
       last SWITCH;
     };
  }
  # analyse our state
  if ( $state != $laststate ) {
    # we changed state
    print "State Change!\t\t";
  }
  print "$laststate\t$state\t$nextstate\n";
}

close SOURCE;