Background on Regular Expressions

I got from Macromedia DEVNET great resources about REGEX

The origins of regular expressions date back to the 1950s when mathematicians began exploring theoretical computer science. This field of research included topics such as automata theory and formal language theory. Stephen Cole Kleene, one of the fathers of theoretical computer science, is credited with inventing regular expressions. Ken Thompson, a major contributor to the development of the UNIX operating system, incorporated regular expressions into the UNIX text editor known as Ed.

Today, support for regular expressions can be found in scripting languages, programming languages, operating systems, and tools. Examples of tools that support regular expressions include Microsoft Internet Explorer, Firefox, Macromedia Flash, Eclipse, and Microsoft Visual Studio .NET. Nearly every modern programming or scripting language offers built-in support for regular expressions or provides a dedicated library as an add-on. Some examples of computer languages that support regular expressions include Macromedia ColdFusion, PHP, ActionScript, JavaScript, Java, C++, C#, Visual Basic .NET, PERL, Ruby, and Python.

Depending on the tool or language, the implementation of regular expressions may vary. Due to the varying levels of support, I recommend that you always find documentation on what is and is not supported by the tool or language that you’re using. There are a variety of reasons why the growth in popularity of regular expressions has taken place. For web developers and programmers, the quantity of code in the world has grown exponentially. As such, it’s become increasingly difficult to navigate the volume of text that is out there. In addition, although regular expressions ancestry stems from mathematics followed by programming, regular expressions can be used by content developers as well to update large amounts of text easily.

More