Managing Sessions and State with PHP (3 tags)
HTTP is stateless. If you've ever written a web application where user data matters, you know that managing that data can be troublesome. There are two kinds of data, though: page and session data. Understanding the differences can help you develop better and more easily. Brian Fioca explains.
Building a Finite State Machine Using DFA::Simple (2 tags)
A finite state machine (FSM) is a general-purpose mechanism for solving common programming problems that involve performing actions based on previous and current input. (They're good for parsers and the like.) William Ruppert demonstrates how to build and use FSMs in Perl.