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Discussion on: Stop trying to be so DRY, instead Write Everything Twice (WET)

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patryktech profile image
Patryk

A good reason to wait until you have three or more repetitions is that it helps you prevent writing abstractions that take ten arguments.

*You may think "oh, this code here repeated here, and here" so you write an abstraction. Then you add a third variation, and realize you need a height argument, so you redefine it with a default of None. Then repetition four requires a colour. And before you know it, your abstraction ends up with 10 different branches and becomes 🍝.

On the other hand, if you do write it in different places, you'll see what the differences are, and maybe abstract it into 3 didn't functions that only do one thing, so you don't end up with abstractions that you end up refactoring anyways.

(*Impersonal you - not saying you're guilty of that, as it gets easier to predict with experience, but good habit to develop early on).

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jondubois profile image
Jonathan Gros-Dubois

This is very well put. There are many ways to abstract something and you don't know what the best abstraction is going to be until you have a large enough sample of sub-problems to be able to make an informed decision.

Choosing the wrong abstraction is costly and leads to complexity bloat because developers have a natural tendency to keep adding new abstractions on top instead of refactoring or deleting existing ones.

Also, every time you invent a new abstraction to reduce repetition, you introduce one more concept that people have to learn in order to make sense of your code and it adds up; especially if the abstractions are contrived technical concepts and not strongly rooted in an underlying business domain.