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Stripe is building a Ruby typechecker

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Re: Stripe is building a Ruby typechecker

#141

Post by Kalium »

amelius wrote: post #132
Kalium wrote: post #111

Earlier quoted context omitted.

How many services do you think a big company like Stripe has? Let's be exceptionally conservative and assume fifty, with a minimum of a million LoC between them. All of them need to keep working for the business to keep working.

Ok, but they also have a lot of developers.

They do! And most of them are considered valuable employees because they can produce features the business wants in acceptable timeframes.

It's perhaps possible that the business and management side of the house at Stripe might not want to give that up for a while so all of those developers can re-implement every service. Given that historically something like half of all rewrite projects fail, there's some non-trivial level of risk there.

Though I understand if some think Stripe can afford it.

Re: Stripe is building a Ruby typechecker

#142

Post by tonyhb »

sankha93 wrote: post #53

Any reason why existing typecheckers for Ruby didn't make the cut? There are projects like RDL [1] which provide similar functionality. I know for certain that people from Stripe were taking a look at it last year from the issues they had raised. Disclosure: I am a grad student, recently started working on RDL. [1]: https://github.com/plum-umd/rdl

Quick plug for RDL. It's pretty great. There are a couple issues with Rails, but for standard Ruby code and modules it's a much better process to read, write, and maintain code with RDL than without

Re: Stripe is building a Ruby typechecker

#143

Post by vinceguidry »

Kalium wrote: post #137
workinthehead wrote: post #134

Earlier quoted context omitted.

Why must you keep telling people "You're absolutely right!" It seems insincere and condescending at best. If you really think you know better than the person you're responding to, use evidence and logic, not cheap conversational ploys.

I do need to mix up the verbiage more. In practical terms, people respond much better to having their egos stroked than they do to being told they're wrong. Evidence and logic work much better when someone doesn't feel like their ego is at stake. Telling someone they're right before pointing out that they could be more right is one way to do this. Telling people that they're wrong is more likely to provoke a defensiv…

You're not supposed to acknowledge insincerity. You're supposed to make up another reason that merges the sincere and the insincere viewpoint together.

Re: Stripe is building a Ruby typechecker

#144

Post by klmr »

vidarh wrote: post #139
emodendroket wrote: post #121

Earlier quoted context omitted.

> A proper Ruby-ish type checker will need to be able to handle that, or it'll push people to write non-idiomatic Ruby. It probably won't be idiomatic (maybe just add interfaces?) but I think duck-typing is overrated anyway. Just because an object responds to a method doesn't mean it's going to do anything like what you expect. To take a contrived example, Array.Shift and Keyboard.Shift are probably unrelated methods…

You don't have that guarantee with interfaces either - you're trusting that the developer isn't lying to you. My experience is that I've more often run into developers that have artificially barred me from doing what I wanted by checking for a given class, than that I've accidentally passed in something that satisfies a given type but does something different.

> You don't have that guarantee with interfaces either

True, but you can give the interfaces/contracts proper names (or namespaces). To use the example in the parent comment, `Array` and `Keyboard` wouldn’t implement the same contract even if both have a `Shift` method.

Re: Stripe is building a Ruby typechecker

#145

Post by cpeterso »

This Ruby typechecker is a similar approach to Facebook's "Hack" language, incrementally upgrading their legacy (PHP) codebase to a new statically-typed language instead of rewriting everything in a new language.

https://code.facebook.com/posts/264544830379293/hack-a-new-p...

Re: Stripe is building a Ruby typechecker

#146

Post by pg_bot »

emodendroket wrote: post #129
pg_bot wrote: post #126

Earlier quoted context omitted.

I don't find it unbelievable, I just personally don't get the appeal because you have to do that work when you name things anyway. e.g. I would never expect a variable named "first_name" to be anything other than a string. It's also fairly easy to handle most type conversions so I would rather be permissive in what I accept (to a reasonable point) than be rigid.

Well what are the properties of config_options or app_user or objects like these? Is it even documented, or am I forced to scan the entire method trying to figure out?

Typically I would initialize an AppUser object and print out its default representation. You can quickly find info on an object by doing something like:

    AppUser.new 
      => prints all properties of the object with nil values 

    AppUser.instance_methods - ActiveRecord::Base.instance_methods 
    => prints all unique instance methods on that class
values

config_options is extremely generic but I would expect that it is a Hash of key/value pairs. Given the fact that it has options in the name you are likely going to have to look it up regardless as you have multiple choices when using it. I'd expect some documentation if it is truly configurable, or you can transparently look at the method signature if it uses keyword args. (say for a library that handles formatting currency)

Quickly reading other people's code is a definite skill. While it can be a pain to do, it is worthwhile since the code is the only real source of truth.

Re: Stripe is building a Ruby typechecker

#147

Post by Kalium »

vinceguidry wrote: post #143
Kalium wrote: post #137

Earlier quoted context omitted.

I do need to mix up the verbiage more. In practical terms, people respond much better to having their egos stroked than they do to being told they're wrong. Evidence and logic work much better when someone doesn't feel like their ego is at stake. Telling someone they're right before pointing out that they could be more right is one way to do this. Telling people that they're wrong is more likely to provoke a defensiv…

You're not supposed to acknowledge insincerity. You're supposed to make up another reason that merges the sincere and the insincere viewpoint together.

Yup. But the Dale Carnegie stuff is exhausting.

I'm sincere in that I want people to listen to my points without getting their egos in the way.

Re: Stripe is building a Ruby typechecker

#148

Post by emodendroket »

pg_bot wrote: post #146
emodendroket wrote: post #129

Earlier quoted context omitted.

Well what are the properties of config_options or app_user or objects like these? Is it even documented, or am I forced to scan the entire method trying to figure out?

Typically I would initialize an AppUser object and print out its default representation. You can quickly find info on an object by doing something like: AppUser.new => prints all properties of the object with nil values AppUser.instance_methods - ActiveRecord::Base.instance_methods => prints all unique instance methods on that class values config_options is extremely generic but I would expect that it is a Hash of ke…

Yeah, of course there are ways of doing it. But if you define types you can in a second be looking at all the possible values. The tools help you be more productive and make fewer mistakes.

Re: Stripe is building a Ruby typechecker

#149

Post by chrisseaton »

qop wrote: post #124
chrisseaton wrote: post #74

Earlier quoted context omitted.

> I think that ruby 3 could lend itself to bring transpiled to crystal relatively easily I think for this to be tractable you'd basically have to implement a complete Ruby interpreter in Crystal and then transpire the Ruby program to bytecode to be run by the Crystal interpreter. So not really a meaningful or useful transpilation any more, and certainly not fast. Even basic things like method dispatch do not have the…

We don't know very much about what ruby 3 types will look like or what other information we'll have. Even a small subset of ruby being transpiled would be a useful thing for some developers. You're much more aware of some of the constraints here than I am, as Oracle doesn't pay me to hack ruby for a living. With a typed AST, there'd be enough information there to build a foundation for a rb2cr tool. I didn't say the…

> Most of the ruby code I want to rescue isn't littered with string-based define_method nonsense.

I see what you are saying - but this is where the issue is I think. You may not write code that does sophisticated metaprogramming, but the gems you use are probably fundamentally based on it. Even just requiring some of the standard library uses a surprising amount of of metaprogramming. For example you can't load something as basic as 'fileutils' without doing a lot of metaprogramming.

The entire Ruby ecosystem is built on metaprogramming.

Re: Stripe is building a Ruby typechecker

#150

Post by workinthehead »

Kalium wrote: post #137
workinthehead wrote: post #134

Earlier quoted context omitted.

Why must you keep telling people "You're absolutely right!" It seems insincere and condescending at best. If you really think you know better than the person you're responding to, use evidence and logic, not cheap conversational ploys.

I do need to mix up the verbiage more. In practical terms, people respond much better to having their egos stroked than they do to being told they're wrong. Evidence and logic work much better when someone doesn't feel like their ego is at stake. Telling someone they're right before pointing out that they could be more right is one way to do this. Telling people that they're wrong is more likely to provoke a defensiv…

The only place this works the way you think it does is in your mind. Any normal person is going to see that and register it as goofy and ingratiating. Like Spock or some alien that thinks it's cracked the human code when really it's nowhere even near the uncanny valley.
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