Why Dynamic Languages? Why Strongly Typed Languages?

From Reddit commenter "munificent", the best analogy of why productive coders use Dynamic Programming Languages and Strongly Typed Programming Languages (best analogy I have ever seen...):

> > So, the problem is that software developers have poor foresight and a complete lack of self-awareness? No, the problem is that the success of most software projects can not be predicted.

Image via Wikipedia

When you go camping, you just pitch a tent. When you're moving, you build a house. With many software projects, it's impossible to tell beforehand if you're just going camping or will be taking permanent residence. It doesn't make sense to spend a month building a new house every time you go somewhere, if 90% of the time you end up leaving after a couple of days. What does make sense, and is becoming a common pattern is this: 1. Stake out a new territory and pitch a tent (v1 in a dynamic language) 2. If it turns out to be a hospitable place, start building a new house next door (migrate back-end services to more strongly-typed languages). 3. Once that's done, ditch the tent and move in (move the production system over to the new back-end). See: twitter (Ruby -> Scala), Facebook (PHP -> Erlang), etc.

Image by ThaRainbowRaider. via Flickr

Yes, a lot of academic computer science completely ignores the economic constraints of software engineering.