Question

I’m familiar with refactoring fairly large code bases in C# and Java but Clojure is something of a different beast, especially since it:

• Has a mix of macros and functions in typical code (i.e. you might want to refactor from a macro to a function or vice-versa?)
• Uses dynamic typing in most circumstances (so you don’t get compile time checks on the correctness of your refactored code)
• Is functional rather than object-oriented in style
• Has less support for refactoring in current IDEs
• Is less tolerant of cyclic dependencies in code bases (making it harder to move blocks of code / definitions around!)

Given the above, what is the best way to approach code refactoring in Clojure?

Answer 1

In “Working effectively with legacy code” Michael Feathers suggests adding unit tests to create artificial “inflection points” in the code that you can re-factor around.

a super brief and wholly incomplete overview on his approach to adding order to unstructured code:

• devide the code into “Legacy” (without tests) and the rest.
• create a test
• recur on both halves.

The recursive approach seemed to fit well with the mental processes I use in thinking about Clojure so I have come to associate them. even new languages can have legacy code right?

This is what I got from my reading of that one book while thinking about clojure. So I hope it is useful as a general guideline. perhaps your codebase already has good tests, in which case you’re already beyond this phase.