Within the subroutine lex, @output refers to the local lexical declared with my. In argout as Fletch noted it refers to the package variable.

The use of $buffer also refers to the package variable. If you were to use strict you would get error messages like:

Global symbol "$buffer" requires explicit package name at ...
Global symbol "@output" requires explicit package name at ...
Global symbol "%states" requires explicit package name at ...
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To get rid of these messages simply declare the variables at the beginning of your source file with either:

my ($buffer, @output, %states);
[download]

or

our ($buffer, @output, %states);
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if they need to be visible from outside the current package.

Knowing this would be one thing, but what I really want is that the $buffer, the @input, the @output, and possibly even the $c would be data inside of a "Dfa" object,

To implement a more object-oriented approach like you might be inclined to do in Java, one usually would proceed like this:

package DFA;
sub new {
  my $dfa = {};
  bless $dfa, shift;   # associates $dfa with the current package
  $dfa->{buffer} = '';
  $dfa->{output} = []; # note: output is now an array reference
  $dfa->{states} = {}; # note: states is now a hash ref
  $dfa;                # return the new object
}
...
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And here is an example of how a subroutine like argout would be implemented as method of the DFA class:

sub argout {
  my $dfa = shift;      # $dfa here is equivalent to 'this' in Java
  my $temp = { type => 'ARG', value => $dfa->{buffer} };
  $dfa->{buffer} = '';
  push(@{$dfa->{output}}, $temp);
}

# example of constructing a DFA object and calling argout:

my $dfa = DFA->new();
$dfa->argout();
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Also note how references to the variables $buffer and @output have changed.

This is just a very cursory overview of how to create a class in perl. For more details, see perldoc perlobj.

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