story
I'm having a really hard time understanding this "I need types forced down my throat" and "I like typing 3x as much as I would otherwise need to" and "yes, I want half my screen obscured by the types of everything I'm doing, not the actual code" and the "adding types now means bugs are impossible" mass cult hysteria that's running so rampant. Typing very occasionally prevents bugs that are generally easy to catch/fix or show up straight away when running an app. It's mostly a documentation system. And it slows development down.
Especially in Ruby which is such an elegant "programmer's language" I think it would just be silly.
Static types do make certain classes of bugs impossible, like missing method bugs, typos, and the like. You can eliminate a large group of defensive programming techniques and trivial unit tests that you would need in a dynamic language to ensure a similar level of confidence in a program. Obviously they don't make all bugs impossible, there will be bugs as long as there are programs, because we write programs without perfect knowledge of the requirements, and this is an unavoidable pitfall of software.
This can depend really heavily on what you mean by "development." If it's just getting the first version banged out, sure. If it includes coming back to code a couple years later in order to incorporate a new business requirement, having that documentation present can be a really big deal. 2 seconds spent typing out a type hint now might, down the line, save several minutes on average. Even in a recent Python project I did over the course of just a couple weeks, when I got to the "clean the code up and get it ready to put on the shelf for now" phase of the project, I ended up wishing that I had bothered to use type hints just a wee bit more when I was banging it out in the first place. It would have been a net time saver.
I don't like static typing super a lot in all cases because it makes it hard to do data-level programming. Which I find to be the true productivity booster in dynamic languages. But optional typing seems to hit the sweet spot for a great many purposes.
For example, JSON describes a logical structure of nested lists and dictionaries. If you were doing data-level programming, you would just map the JSON into actual nested lists of dictionaries and get on about your business.
The alternative, which is more common in static languages like Java, is to transform it all into some set of domain model objects, and probably validate it up-front, too. Even the bits you don't actually need to look at in order to accomplish the job at hand. IMO, that approach tends to mean creating a lot of unnecessary work for oneself. It also makes it harder to obey Postel's law.
(The corollary to that last bit is that it is also possible for static typing to create bugs.)
A personal example of this was Httpd used to accept standard headers with spaces instead of dashes, this leads to strange behavior if you accidentally include both. So they decided to stop doing that in a major version. This major version was opaquely included by ops accidentally into our base images. This lead to a very long day of debugging on our end.
Point is, by being liberal with what you accept you create ambiguity, which you may not totally understand at the time. By putting that out into the wild you basically are forced to keep this ambiguous, undocumented spec alive or you no doubt will end up breaking some client.
One way is to treat the JSON as a generic JSON structure, and traverse it manually. Of course, you will have to be explicit about what should happen when children are of different types from what you expect, though this explicitness could just be throwing an exception or ignoring it. Haskell's Aeson and Rust's serde_json both support this, as does .NET's JsonElement type.
Unfortunately, this means you're passing around a lot of objects called something like "JSON" without any information about what they contain at the type level, and as an alternative between that approach and creating domain objects, there are row polymorphic records, which allow you to write functions that accept any record that has certain fields, and also specify that they may also contain other fields which you do not handle. This allows you to program to what you know about the types you're ingesting without having to write a lot of new types.
This is not true. You could paint almost every language feature aimed at producing correct software in this way: "writing tests makes me type more, and they catch very few bugs that would have been shown when running my app anyway". (Or, as an ex coworker once told me, "I don't need to write tests because I never have any bugs").
And what are types if not a kind of test/proof that the computer writes for you?
> And it slows development down.
There's a software development adage that goes like this: "I don't like writing tests, because they make me waste time I need to fix bugs on production that weren't caught because I don't write tests."
Well, I guess this is also a matter of perspective.
From where I'm standing, I'd rather you slow down and "document" your code. Code written at the speed of thought makes for an awesome MVP and for an awful legacy for your co-workers.
In the course of my job I write Swift for iOS and Ruby for server APIs and our web-based UIs.
Type issues are about 0% of my Ruby bugs, but dealing with all the damn type requirements in Swift regularly takes dozens of minutes to track down when some weird esoteric error message pops up. And God help you if you try to use generics.
If you want strong typing, then good for you. Just pick a language that fits that mold.
So much of what I love about Ruby is what it doesn't make me do.
I'm sure there are developer/projects that both enjoy and benefit from static typing and strict type systems of various kinds. I just want Ruby to remain a place for those of us who aren't in those positions.
However, even with TypeScript ascendant, the vast majority of people programming JavaScript write vanilla dynamic JS. I don't think dynamically typed Ruby is ever going to die. Whether large enterprise codebases will standardize on requiring type signatures is a different matter, because the benefits always outweigh what downsides you see in static typing once you surpass a certain scale.
Doubt.
In my experience at least 70% of bugs are ones that you'd catch by using types - things like x instead of y, possibly-empty list instead of known-nonempty list, user ID instead of group ID. Logic errors that couldn't be caught by typing do exist, but they're very much the minority.
70%+ of bugs I deal with are business logic issues that no type system could solve.
Sure, as I code I run into an occasional nil object or NoMethod error, but those last as long in Ruby as they do in Swift (about 2-5 minutes while working on that specific part of the code).
The actual bugs I have to fix are nearly always business logic issues. Edge cases around 3rd party integrations, incomplete implementations, unintended side effects, etc.
3x? Even on languages that do not support type inference I would say that this is at most 1.1x. Even then, type inference exists.
> adding types now means bugs are impossible
I usually see that as a mis-representation of what type advocates say. Rather, it seems that people just support that types reduce the amount of bugs.
> or show up straight away when running an app
Or that show up after you had said app running for a while, and then you get a run-time type error which appears only after doing certain actions. This is the main reason that I am avoiding languages like lua and python.
(In addition languages with more advanced type-systems allow you to catch bugs such as buffer overflows or division by 0 at compile time)
