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Comment by FuzzyDunlop | Hacker News Reader

I'd like you to offer some examples of code that successfully documents its own raison d'être - in a way that a comment couldn't do better - instead of repeating this 'crutch of poor developers' rhetoric.

I mean, I can write self documenting code without any comments, and it's perfectly understandable.

    before_create :auto_increment

    def auto_increment
      self.count + 1
    end

That code fails to tell the programmer why it's in the application logic and not defined in the database schema. What should I do instead, so I can code without crutches?

    def auto_increment_natural_key
        self.count + 1
    end

That's not a great deal better, it's still just saying what it does, not why it's there in the first place.

    def auto_increment_natural_key_because_another_app_relies_on_it
        self.count + 1
    end

Is that it?

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Your code doesn't actually seem to do anything, so a comment would either be contradictory to the code, which is confusing, or explain why your code does nothing, which is silly.

I would argue that in this case, it is far better to just understand the code and then fix it appropriately. A comment would leave you second guessing.

    def auto_increment
      self.count += 1
    end

(though, for the purposes of self documenting code, count probably is not a great variable name either)

Rather ironically, it appears my poor choice of example could have done with some more documentation.

I'm now curious to know what you would have written for documentation.

Though, I think your example turned out to be a great one because it highlights that not everyone reads code the same way. Personally, I load large segments of code into memory and then mentally step through. You left me wanting more to see the context in which the method was to be executed, but I didn't really feel the need for comments.

However, with just the one method that you wrote in your example, that seems to indicate that you read just one function at a time. If you are not observing the code as whole, I guess a comment would help. I often find them taxing though, as they have to be read into memory as well.

I think that discrepancy is why the comments vs. self-documenting code debate exists.

The problem was I initially hinted at the context in my first example, with a call to Rails' `before_create` callback method. I then omitted it from every other example, thinking it'd be inferred. Evidently that wasn't very clear.

But the way in which people read code is an interesting point, which I actually think might be worthy of its own discussion. Looking at the psychology behind this would be good, I think.

> Evidently that wasn't very clear.

Actually, I would say your intent there was quite clear, which is where I came to realize that the code did nothing. Without that context, one could assume the method was used for its return value where the code could very well have had purpose as written.

What wasn't clear was how the count attribute was intended to be used throughout the rest of application. In the real world I would start to build a mental model around the uses of count, which was not available from your example. In terms of self-documenting code, I liken a short code snippet like your example to a sentence fragment in english. The entire sentence, or statement if you will, encompasses much more of the codebase.

This is definitely an fascinating topic, but unfortunately one that is very difficult to discuss for many reasons. I wonder how we can dig into the physiology aspects that you raise without the prevalent "my way is the only true way" attitude?

Thanks for trying!

Now we just put the comment in the variable name. The compiler just checks the variable names all match up, but doesn't check whether their names make sense.

Perhaps the example chosen was too much of a toy to yield valuable insight?

That code fails to tell the programmer why it's in the application logic and not defined in the database schema

Why isn't it a GUID? Why is it 32 bits instead of 64? Why is it signed yet starts at 1? Why isn't it a string? How will the identities be merged?

The notion that answering one single question provides clarity is ridiculous.

def auto_increment_natural_key_here_because_if_a_product_doesnt_have_a_key_assigned_because_it_came_back_from_return_and_wasnt_assigned_on_during_the_recieve_shipment_process_the_key_doesnt_exist_and_another_app_relies_on_it

Pretty sure that's it.

Your sarcasm is screwing with HN's page formatting.

This is what element inspectors/editors are for. Snip, snip.

I had to use inspector to make the page readable, but it's a PITA. GP is a jerk.

Agreed. Just pointing out there's a workaround.

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