Domain Expert

From APIDesign

Once one has domain knowledge of some subsystem, it is easy to become a Domain Expert. Then it may seem easy to design some APIs for the domain. However without understanding the API Paradoxes the quality of such API may not be high. It likely going to cover the domain field, but the API usability or readiness for evolution will very likely suffer (unless such Domain Expert reads TheAPIBook first).

However can it work backwards? E.g. can one be just an API expert and then design good enough API without appropriate domain knowledge?

I am now participating in an experiment that will check that. OracleLabs guys asked me to help them design Truffle interoperability APIs. I do understand bit about Truffle, but certainly I am not a Domain Expert, yet I am supposed to design something as complicated as API to allow mixing of languages: imagine part of program written in Ruby, part in JavaScript, part in Java with objects floating between these languages without any borders!

This is a new situation for me: In case of NetBeans or in case of HTML/Java APIs, I was also the architect of the system. I knew it by heart. Now I barely understand how Truffle works and what makes it the fastest execution system for dynamic languages. My biggest fear is that I will design something that will be inherently slow.

But on the other hand, if I can design easy to use APIs for Truffle, then I can create a perfect API facade around everything! Soon we'll have a chance to see whether one can be good API designer without being real Domain Expert.