Unless there is clear evidences upfront that the project will be a piece of software where local performance is highly critical, it makes sense to favor code readability and maintainability over optimality.
Of course, you can have different level of code quality whatever the paradigm retained. Most languages out there will allow you to mix different paradigms anyway.
Given this fact, we would surely better served with an article like "When to favor expression in each paradigm available in your favorite language".
In my experience, software engineers "think" imperatively. First do this, then do that. That's what we do in everyday life (open a random cooking book..) and that's also what the CPU does, modulo some out-of-order and pipelining tricks. A declarative style adds some extra cognitive load upfront. With training you may get oblivious to that, but in the end of the day, the machine does one thing after the other, and the software engineer wants to make it do that. So, either you express that more "directly" in an imperative style, or try to come up with a declarative style which may or may not be more elegant, but that this ends up more readable or maintainable is on the functional proponents to prove.
It’s funny you mention recipes, because i’ve always been frustrated by traditional recipe descriptions that muddle concurrency and make it difficult to conceptualize the whole process. E.g. the table structure here is superior to step by step http://www.cookingforengineers.com/recipe/158/Dark-Chocolate...
Tbf, I agree with the recipe criticism. Would be neat with a dependency graph instead of a step-by-step list of things to do when baking a cake. Would have saved me a lot of headache in the past. (The table in your link expresses a tree, which is probably sufficient for most purposes.)
I hear this often. In the past the claim used to be that they "think" object-oriented. This is a thinly veiled argumentum ad naturam.
> ... on the functional proponents to prove
Prove your own claims before you demand proofs from other people. And by prove I mean really rigorous thinking, not just superficially seeking confirmation for the things you already believe either way.
B: Prove it!
A: No, you prove first! With really rigorous thinking, please!
It is terrible on a system level with concurrent execution, there you really need all the safe guards.
Sure, but let's also not confuse "optimal" with "reasonable". One of the major challenge of modern programs is how slow they are at every level. Very often, this bad performance can be attributed to a style of programming that tries to completely ignore that the program will run on a real machine with real hardware. A little bit of mechanical sympathy (e.g., operations that make good use of the CPU caches or don't confuse the branch predictor) can yield a program that is 10x faster than a naive implementation, with little to no loss of readability or maintainability. (In fact, as noted by Nelson Elhage [1], faster programs enable simpler architectures, which helps make them more readable and maintainable.)
In FP languages, programmers face an extra difficulty: the distance between the code they write and the machine code that will be executed is greater than in languages like Rust or Go. They will need to be knowledgeable about the language, its libraries, and its compiler to avoid the pitfalls that could make their programs slower than would be reasonable (e.g., avoiding unnecessary thunking in Haskell).
[1] https://blog.nelhage.com/post/reflections-on-performance/#pe...
First of all, one of those languages is not like the other (Go is closer to JS than to Rust) - second, we really can’t reasonably guess at the produced assembly, even C compilers do some insane transformations leaving the code nothing alike the original, let alone more expressive languages.
