Regex-engine

With all the features of the engine finished the only question left is, what would have changed if instead of a NFA engine we had made a DFA engine?

Backreferences match the same text captured by a previous capturing group. To implement them, we need to evolve the concept of matchers/transitions.

Atomic groups can be used to avoid unnecessary backtracking and optimize regex. In this post we explain them in detail and add them to the engine

We finally modernize the interface of the regex to allow searching for multiple matches

The start and end of string anchors (^$) allow to check that a string starts or ends in some way. We'll implement this and in the process add the first regex mode: multiline

With character classes you can test if a character is inside a certain set of symbols. This makes regex simpler and more expressive

A formal regex engine is cool but kind of useless. The first step to improve it is to implement capturing groups

We complete the engine for formal regex by translating a regex engine to a NFA

Let's talk about exacly what's a finite automata, its two types (DFA and NFA), and how to implement a NFA

Just enough information about formal language theory to answer "What is really a regex?" and "How are they executed?"