Regular Expressions: Action, Pattern, Modifier

Introduction to Regular Expressions

In our introductory article on Perl Regular Expressions, we showed how regular expressions can cut down the code that you have to write. This article discusses the format of regular expressions.

Perl Regular Expressions

Introduction to Regular Expressions

Regular expressions are used to match, change or translate strings against a pattern. In a traditional programming language, you will need to write a routine that scans your string and then do whatever you need to do. This approach is acceptable if the pattern is fairly simple. However, if your pattern is complicated, you will have to write a complicated routine to do your matching and comparing and translating.

Introduction to Perl

What is Perl?

Perl was originally developed with an emphasis on system management and text handling. However, as it was revised, other features were included such as regular expressions, signals and network sockets. If you have programming experience in any language, you can easily learn Perl.

Accessing SQL Databases in HTML::Mason

Introduction

In the past 3 articles, we discussed about the different components of HTML::Mason. Most web sites require database access so when you create your HTML::Mason pages, you should also consider this.

Perl IO::Sockets

Introduction to IO::Sockets

A client and server program works this way. Simply put, a client requests a service and a server services the request. There are several ways to do this. The crudest will be to call a program within Perl and pass the parameters during the call. Another way is to use pipes.

A program can call another program but the input to the called program will be passed through the STDIN of the other program. Both methods are crude and allow only for simple passing of input and output. Another way to do this is using sockets.

Sockets allow two programs to communicate with each other. The server binds a port on the machine. The client connects to that port to communicate with the server,