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Comment by necovek | Hacker News Reader

Please be afraid of types.

On top of new cognitive load, introduction of redirection, and anti-patterns like pretend-simplification where you shuffle a bunch of unrelated parameters into a struct to make a function receive only a single argument (which quickly evolves into functions receiving parts of that struct they don't need, making use and testing much harder — I am surprised an article is really recommending this as a strategy), your types frequently get exposed to external users, and you need to start thinking about both backwards- and forwards-compatibility.

Benefits of types should be carefully balanced against the cost of introducing them, and while calling that "fear" might not be appropriate, it should be a conscious cost-benefit analysis.

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It's more cognitive load to write a validation for every parameter because you can't rely on your fellow dev knowing it's not good to pass a string where you want a boolean.

I think you misunderstood the article and my comment: this is about introducing new types, not about typing or not typing your function arguments.

But new types are wonderful! They can be used to prevent you from adding speed and and fuel left. Yes, both speed and fuel left are floats, but adding them will only produce nonsense.

Which is an altogether different discussion: the OP focused on compound types, and not on type "aliases" and their benefits.

Most languages and their typing systems would still allow adding speed and fuel-left if you only aliases them, so you are likely going to need to sacrifice ergonomics by wrapping them in a compound type instead.

Conversely, do you also consider the downsides and consequences of not having types? If you don't, then you're blind to whole categories of issues. As a good engineer, you need to be able to reason both ways to come to a reasonable solution, not just one that conforms to your particular ideology.

How do you understand the sentence above:

> Benefits of types should be carefully balanced against the cost of introducing them

Does "benefits of types" not imply to you that there are downsides to not having them?

The rest of the comment was clearly framed in a way that any cost of not having types might as well not exist. Reinforced by the very first sentence of how one should be afraid of introducing types.

Is it uncommon to focus on the things that support your counter argument in a discussion?

Does one need to always "fairly" represent both sides when it's clear that there are obvious properties that you are not discounting? This is a discussion, and that was a single comment — I couldn't imagine people would see it as a comprehensive look at a topic as complex as types in programming.

In that case, why not respond to the arguments I raise but instead attack what was never stated? I can see how part of the comment can prejudice you to an unbalanced opinion, but that's more on the reader than on the author — at least I think so.

You need to think about backwards and forwards compatibility either way, types help make that easier.

Not when they are misused, which is quite common.

The example of the article is a great one: replace all your arguments to a function with a single argument of a new "type".

Soon, this new type gets used in another function, and it "just" needs another field added. Suddenly, you inadvertently changed the API for the previous function.

So yes, you need to worry about backwards and forwards compat either way, but misusing types will make it harder and more error prone.

Instead, if you carefully used types only when they really represent a new logical thing, you wouldn't replace unrelated set of arguments with a single argument of a new combo type, and code would be cleaner and saner.

There's always types. The question is if they're dynamic, static, implied or explicit.

You seem to be talking about "typing". The article uses "types" for introduction of new classes/structs (eg. typedef in C), and I carried that terminology over.

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