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0 pointsduped2y ago0 comments

> Type checkers shouldn't get in the way of your code compiling.

I don't get it, what's the point of type checking if not to reject invalid programs? The point of a type system isn't simply to add annotations to a programmer (and some type systems can omit them entirely) but to define the subset of programs that are correct within the set of all the programs that can be expressed.

I understand (and have used in production) optionally/gradually typed languages, and without fail codebases will opt for using types up front and not ignoring type check failure because they are always incorrect.

A type error is the compiler/run time telling you "I don't understand what you told me" so why do you want to ignore that?

And if the point is that you want to be able to change the type signature of something without having to refactor giant chunks of code, then that suggests your code is structured poorly to begin with. It should be easy to pull in what you need and play with it without affecting everything else if you haven't done a bad job of architecting the codebase.

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4 comments · 4 top-level

ativzzz2y ago

Because often, and especially with heavily interactive programs like games or UIs (any web page), you don't know if something will be good or not until you build some working version of it. The more barriers there are (type checkers, compiler errors, etc), the longer it will take you to prototype something usable to check if what you're building is good.

Sometimes, it's useful to bypass these things for a prototype and you don't care if it crashes on any edge case. This is why typescript is so popular on the web - you can quickly prototype something with JS, then once you find the right solution, add types and productionize the code

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whoknowsidont2y ago

>I don't get it, what's the point of type checking if not to reject invalid programs

It can take longer to think about how to properly type instead of just writing some code, testing it out, and immediately seeing if something is wrong. You also often get into a situation where linters who like to act like type-systems give you arcane errors (looking at you TypeScript).

In the moment I just want to move some data around and quickly try out an idea, I don't need it to be resilient or perfect.

Xeamek2y ago

>I don't get it, what's the point of type checking if not to reject invalid programs?

Because not every program that doesn't compile is necessarily invalid.

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lelanthran2y ago

>And if the point is that you want to be able to change the type signature of something without having to refactor giant chunks of code, then that suggests your code is structured poorly to begin with.

The article addresses this, multiple times. In brief, the "poor structure" isn't the problem.

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