Hacker News Reader

Comment by funcDropShadow | Hacker News Reader

I am a former fan of extreme static typing, think Haskell higher-order type-classes fan. So, yes, I understand the value. But everything you build is very brittle in the face of changing requirement. When requirements seem to change because developers are still learning the domain, that is fine. This churn is unavoidable, true. But, if you have business people tell you, you have to pass some additional information through your system without doing anything to it, and you answer, I have to refactor all my type definitions, then you have some explaining to do.

View on HN

> But everything you build is very brittle in the face of changing requirement.

It's supposed to be 'brittle', in the sense that the compiler verifies your code and if the logic changes, the compiler complains. Everything else is a bug.

> But, if you have business people tell you, you have to pass some additional information through your system without doing anything to it, and you answer, I have to refactor all my type definitions, then you have some explaining to do.

And the explanation is that this is software development, there is no "without doing anything to it". If there's a new requirement I need to adapt the code - take it or leave it, I'm not a wizard. And yes, I have done that already in some form and it was almost always received properly. 'Business people' sometimes have no understanding of software development.

The logic "code changes -> only dynamic typing" isn't valid, in my opinion.

> I have to refactor all my type definitions

The data model did change though. Adding an extra field, even if you don't use it, changes the shape of your data.

Ultimately your data is going to be typed with or without your approval. It's unavoidable, because eventually the data needs to be bits on a disk or on the wire. It's just a matter of how aware of it you want to be.

If you can reasonably keep the shape, and all possible shapes, in your head then fine. But I think you'll find this becomes less feasible as systems grow, and even less feasible in a corporate environment when teams come and go.

Reply on news.ycombinator.com