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Comment by yakubin | Hacker News Reader

Tbh, to me the first one is easier to read. There's less jumping.

But both are terrible. It should just be a bunch of if (...) { ... } else if (...) { ... } else { ...} etc. with no mutation of variables (what are all those v += 1 for?).

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Those v += 1 implement the exact specification given above:

    1. Parse an integer N from a string.
    2. If N is NaN, fail with an error. Otherwise, increment N by 1.
    3. If N is > 3, fail with an error. Otherwise, increment N by 1.
    4. If steps 1-3 failed, set N to 3.
    5. Increment N by 1.

Those are quite strange requirements, and the resulting second code looks strange too, but... it faithfully and obviously correctly represents the given specification.

It's the kinda assignment where you should look at a higher level - what does it do? What is N used for? What are the possible inputs?

I mean if you start with a set of tests instead of pseudocode written down in text you could probably write something smarter.

The example is strange and contrived. I couldn't torture the logic enough to demonstrate how readability breaks down with exceptions. Reading through the comments, I realise that even if the code is unreadable with exceptions, it can be rewritten to be readable. I updated the article to highlight not only readability, but also compositionality. I also tried to draw parallels with Promises (which are also monadic). I tried to target the article to intermediate programmers that may not already know most of the concerns raised in the comments, and I surely can't cover enough space on error handling without writing a book.

Thank you for the comments. I've learned more from reading the comments.

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