## Looking at Regex in Rust (Addendum)

Hi. In my previous article Looking at Regex in Rust. I covered some basics. Today I will go over some new things that I have learned, as I expanded on things that my regex expression needs to handle. In particular the need to handle the possible existence or none existence of qualifiers +,-,~,?.

## Looking at Regex in Rust

If you have been following this series, you might know that I am playing with SPF records. I have turned my eye to a and mx mechanisms. As I started looking at the a mechanism. I noticed that my current approach using the standard string functions would probably be fairly difficult to implement. So I started to think about using the Regex crate. So this will be a look at how that went. The challenges and the things that I took away from the experience.

## Rust Basic Testing

As I work through learning rust, I figured it was time to to start doing actual testing.

## Why Test

Simple, it’s really essential when building anything beyond a few lines of simple code. Being able to run a series of reproducible tests as you develop; allows you to ensure that changes you make are not breaking exisiting code. You also have the option to develop using TDD.

Of course I have not adhered to any of this as I explore the basics of working with rust. But things are progressing and I should now see how testing basically works in the world of rust.