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You Don’t Know Anything About Regular Expressions: A Complete Guide. Regular expressions can be scary...really scary.

You Don’t Know Anything About Regular Expressions: A Complete Guide

Fortunately, once you memorize what each symbol represents, the fear quickly subsides. If you fit the title of this article, there's much to learn! Let's get started. How Regexes Work. Mark-Jason Dominus Copyright © 1998 The Perl Journal.

How Regexes Work

Reprinted with permission. This isn't an article about how to use regexes; you've probably seen plenty of those already. It's about how you would write a regex package from scratch, in a language like C that doesn't already have regexes. I'll demonstrate a new module,, which implements regexes from nothing, in Perl. Regular Expression Library. The Regex Coach - interactive regular expressions. Abstract The Regex Coach is a graphical application for Windows which can be used to experiment with (Perl-compatible) regular expressions interactively.

The Regex Coach - interactive regular expressions

It has the following features: It shows whether a regular expression matches a particular target string. It can also show which parts of the target string correspond to captured register groups or to arbitrary parts of the regular expression. It can "walk" through the target string one match at a time. It can simulate Perl's split and s/// (substitution) operators.