Rule of Three | Hacker News Reader

Rule of Three

en.wikipedia.org

19 pointsrevskill22 comments

I find bad abstractions to be a much greater liability than unabstracted code that could be combined into one function but isn't.

It's relatively easy to combine code and much harder to disentangle it

I second this. Only remove duplication when it either becomes super obvious or painful.

Cloning things makes maintenance harder linearly. Generalizing things makes maintenance harder exponentially. Counterintuitively, generalization only makes sense on small numbers or reiterations, not the vice-versa.

I started https://wordsandbuttons.online as an experiment in zero-dependencies architecture. No third-party, no self-reference. Every page is completely independent. I was told, that as it grew, it would inevitably become impossible to maintain.

Five years passed, including a two-year pause for writing a book. I did more than half a hundred interactive tutorials and quizzes, and continue to add them when I have time. The thing simply refuses to go "too complex to maintain". All the maintenance problems I ever faced with this design were handled within minutes. If there is too much typing, I write a Python script. If not, I do the change manually, replicate it in a few pages, and go on.

As a free bonus, since all my pages are essentially hand-written, no dependencies = no uncontrolled growth, they are all fewer than 64 KB each. Ultra-fast to load, and I never get a "Reddit effect" since even 1000 requests a second is only 64 MB of data. It's green then tea too. I usually have a few hundred thousand visitors a year, and they barely consume enough electricity to boil a kettle of water.

I think this rule of three, like many others is just an attempt to escape well-known complexity issues by putting them under a carpet of less known complexity issues. I'm very happy to have ignored it when considering design for my site.

This looks like static pages. Not sure what your code style has to do with performance in that case. Even if it had ephemeral state 1000 rps for in memory data is trivial.

I prefer WET: Write Everything Twice, which I believe carries the same principle and has the nice appearance of being something of a counter to DRY

I honestly thought I made this up myself. I've told so many people over the years about the rule of three. I guess there's a chance I saw this before and forgot, or that I converged on the same rule.

In trying to look up the scientific word for this, I discovered "cryptomnesia" [1], which I certainly did not invent myself.

Not sure if this is actually describing your phenomenon, it might also be "unconscious plagiarism".

[1] https://en.m.wikipedia.org/wiki/Cryptomnesia

This does seem like one of those rules that would be independently developed by many experienced developers, so neither is hard to believe.

Ha! I thought this the survival “Rule of 3s”:

  * 3 minutes without oxygen
  * 3 hours without shelter
  * 3 days without water
  * 3 weeks without food

I was confused about the 3 hours without shelter bit, as it seems most people would be totally fine without shelter until around the 18 hour mark. But there is some important context:

- You can survive three minutes without breathable air (unconsciousness), or in icy water.

- You can survive three hours in a harsh environment (extreme heat or cold).

- You can survive three days without drinkable water.

- You can survive three weeks without food

Interesting, I thought water was more important than shelter. But sources cite the same.

Same thoughts on shelter vs water. But maybe there’s an assumption that there’s a barrage of elements or the environment.

Try walking with shirt and jeans in windy rain. After a hour or so, it will feel like torture. I can see why they put shelter over water.

Makes sense. The fact that it’s not immediately clear to me, makes me believe I’ve had a sheltered life (pun intended).

I should go out more often aside from usual city running or going to the beach.

The list is mostly for orienting around priorities. In a survival situation, what is truly most important to do next? Is it worth looking for water when you don’t have a shelter yet?

I am using rule of two. I refactor at the second appearance. I started doing this when programming Ruby on Rails a few years back, where DRY (Don't repeat yourself) was a big thing there.

I am using rule of 1.5. It's just like rule of 2, but I also name (e.g. make a separate function) any block of code whose result value is not obvious from a single glance.

That's a mistake that leads to premature generalization

It's a mistake to pick any of those rules as an absolute truth. It varies by task, maintenance and time constraints. DRY makes a lot of sense in some cases, but some others even need a rule of four+ (think of heuristics-heavy code). IMO DRY is most useful when working on a codebase owned by someone else than you.

Never heard of this rule of three, I was expecting this one: https://en.wikipedia.org/wiki/Rule_of_three_(C%2B%2B_program...

I usually share this timeless gem: https://blog.codinghorror.com/rule-of-three/amp/

I have linked to this so many times over the years. Very cool to see it on the front page.

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