Completely agree. Having great automatic tests makes you move so much faster and drop fixes into production with justified confidence.

One of my favourite books. Read it three times.

Not my experience at all. I write code every day and our customers pay real money to use it.

I have used simulators to develop hard-to-make-correct distributed code.

It helped me find all kinds of subtle non-intuitive bugs that would have gone unnoticed had I only used hand coded automatic tests.

Highly recommended.

This is a solved problem. See CakeML for example.

Monads in Haskell is just a way to combine two functions into one when the output of the first function doesn't match the input of the 2nd function.

That's all there is to it.

It is not a way to "box values". Yes you can use it for that if the functions you combine happens to operate on "boxed values" (like Maybe) but that has nothing to do with the fundamental idea of what a monad is.

And yes there are "monad rules" that ensures that combining the functions "makes sense". But people sometimes use monads in Haskell that doesn't actually follow those rules. But it works fine anyways for whatever they are doing.

I recommend that the author actually tries this approach on a reasonably sized project before recommending it to others.

I have tried different approaches and ended up with a single small bus of raw materials (coal,cobber,iron,stone) with everything else hanging off it. It scales amazingly well and avoid spaghetti layouts.

Oil stuff is done separately and fed into the structure where needed.

> "Any sufficiently complicated program contains an ad hoc, informally-specified, bug-ridden, slow implementation of half of Common Lisp."

I have never seen that in practice (30+ years of industry experience working on very large applications).

I think it is one of those statements that fans of Lisp love to quote (a lot) without having any empirical data to back it up.

And yes I am sure that there are examples out there. You can probably find examples of anything if you look hard enough. But that doesn't make it a general rule.

I use a custom code generator for that. It works much better than trying to explain to an AI exactly what I want. Yes it’s a it more work up front but worth it IMHO.