How can I determine if two Scala functions are equivalent? For instance:
scala> def addOne(num: Int): Int = num + 1
addOne: (num: Int)Int
scala> def increment(num: Int): Int = num + 1
increment: (num: Int)Int
addOne == increment
What other methods exist to compare their functionality?
hey, try using property based testing with scalacheck. pump in lots of random inputs so you can compare outputs across many cases. it’s not a formal proof but works for most real-world uses. also, think about side effects and lazy evals sometimes.
Another approach involves statically analyzing the functions, particularly when they are pure and operate over a finite input set. In cases where you can enumerate all possible inputs, you can compare the outputs generated by each function by fully covering the domain. This brute force method may be feasible for simple functions and small domains but quickly becomes impractical as complexity or domain size increases. Furthermore, you might also consider instrumenting or logging behavior during execution to inspect intermediate states, although this is more ad hoc. Ultimately, a blend of domain reasoning, static analysis, and targeted tests is often necessary to draw reliable conclusions about functional equivalence.
I faced a similar challenge in my previous project and approached it by carefully verifying that both functions upheld the same invariants under various test cases. I repeated tests with a comprehensive set of inputs to ensure outputs matched and reviewed the underlying logic of each function. Although this method isn’t formally rigorous, it improved overall confidence in their equivalence across expected scenarios. In projects where thorough verification was essential, I also combined this with code reviews to check for even subtle behavioral differences.