RR 318 Metaprogramming with Jordan HudgensToday's Ruby Rogues podcast features Metaprogramming with Jordan Hudgens. We have panelists Jerome Hardaway, Brian Hogan, Dave Kimura and Charles Max Wood. Tune in and learn more about metaprogramming![00:02:00] – Introduction to Jordan HudgensJordan is the Lead Instructor at Bottega. Bottega has locations in Salt Lake City, Utah and in Phoenix, Arizona. They’re a full-stack development code school.[00:02:55] – MetaprogrammingMetaprogramming was one of those scary concepts. At the code school, when the students learn about metaprogramming and how it works, you can tell that it’s definitely a pretty exciting thing. Its formal definition is it’s a code that writes code. It can dynamically, at run-time, render other methods available to the program.[00:04:10] – Use cases for metaprogrammingThe best use case that Jordan has ever seen is implemented in Rails and that’s code that can run database queries such as User.find_by_email. By passing the email, it will go and find the user with that particular email. Now, there is no method in active record or in the user model that is called find_by_email. That’s something that is created at run-time.Another one is something that Jordan has implemented and that’s a phone parser gem. It essentially parses and validates a phone number. It also has a country code lookup. With all the countries in the world, that would be very time-consuming. But within 8 lines of code, it could do what a hundred lines could do without metaprogramming.[00:06:50] – Performance implicationsJordan never had performance issues because the generation of methods is not something that’s incredibly memory intensive. You might run into that but it would be a poor choice to do in terms of readability.In Brian’s experience, it comes down to the type of metaprogramming you do. If you have a bunch of logic somewhere and method_missing, that’s going to be a performance bottleneck. And if you’re generating a bunch of methods when the application starts up, it might increase the start-up time of the application. But after that, the performance of the application seems to not have any fluctuation at all.