<@U2E974ELT> any good articles discussing “Kotlin-...

# codingconventions

[hudsonb]

@elizarov any good articles discussing “Kotlin-style design and prefer extensions over members”?

[Czar]

main principle is, make your classes lean - with only basic properties and functions, and implement additional module specific functionality via extension functions in respective modules.

[Czar]

For example if you have a User and you want to calculate a discount for one, you could write a member function calculateDiscount or in the mentioned style, you would have user-pricing module where you'd have User.calculateDiscount extension function.

[Czar]

This way you're able to manage concerns separation much better than without it. In Java to achieve the same you'd use services and/or utility classes, which would not be as readable: user.calculateDiscount(TODAY) vs DiscountCalculator.calculateDiscount(user, TODAY)

[Czar]

This is only a synthetic example, but I hope it conveys the main idea.

[Czar]

Here's a much more elaborate and complete explanation of when to use extension functions: https://stackoverflow.com/questions/35317940/when-should-one-prefer-kotlin-extension-functions?answertab=votes#tab-top

[wakingrufus]

That makes sense. What about in the context of writing a DSL?

[hudsonb]

That stackoverflow thread is the best I’ve found in the topic as well