pfun VS python-lenses

Another examples: pfun - stuff you'd find in FP language, but in Python (like using monads for effects)

I am a long-time Coconut user, so functional ideas are relatively easy to play with. But I recently discovered pfun which has a lovely system for Effectful programming.

In pfun 0.12.0 the interpreter for the effect system was completely re-written as a Python C extension. Lets do some benchmarking to see how big a difference this actually makes in terms of performance. We'll use the performance of the the Scala library ZIO as a baseline, as the pfun effect system draws most of its inspiration from there. ZIO has a fairly extensive benchmarking suite. The most obvious benchmark for testing raw interpreter speed, without any parallelism, is called deepLeftBind (bind is the canonical name for the and_then operation, also called flatMap in Scala):

python-lenses

Now, the thing you're doing can be done with something called lenses. But they're rather hard to learn, and really not something I would recommend for a beginner. But there's packages like this which enables you to compose a function that will succinctly parse the thing you're interested in and give you good error messages.