Elm in Production: 25K Lines Later

Re:Elm in Production: 25K Lines Later by amimetic on Monday July 31, 2017 @04:28AM (#14890324)

In exchange you get incredible validation of your JSON and precise error messages about missing fields etc.

And you don't have to write that bit by hand:

http://eeue56.github.io/json-to-elm/

will generate the decoder for you for straightforward cases and give you a great starting point for more complex cases.

You also get proper ADTs to manage state: not asked/loading/loaded/error something that is tedious and error prone in Javascript.

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Re:Elm in Production: 25K Lines Later by dmitriid on Monday July 31, 2017 @04:40AM (#14890372)

Yup. There are a bazillion libraries now trying to pretend to make it look like it's easy to deal with JSON in Elm.

An online converter is definitely not something I would advertise for a "production-ready highly productive amazing pragmatic language to be used in a serious company"

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Re:Elm in Production: 25K Lines Later by dmitriid on Monday July 31, 2017 @05:32AM (#14890550)

For god's sake, Elm is the only language I know that has _an entire book written on how to handle JSON_: https://www.brianthicks.com/post/2017/01/06/announcing-the-j...

It's introduction is: "You know how it takes so much effort to produce even the simplest of programs when JSON parsing is involved? Wouldn’t it be nice if you could breeze right on by that step and get on with writing your business logic? This is what you’ll get with The JSON Survival Kit, a short ebook on JSON decoding in Elm."

Wut

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Re:Elm in Production: 25K Lines Later by Skinney on Monday July 31, 2017 @12:30PM (#14893438)

And Go has an entire book on how to use the database/sql package. Does that mean the database/sql package is hard? Is React difficult because there is online courses? Is Bootstrap? Of course not.

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Re:Elm in Production: 25K Lines Later by enalicho on Monday July 31, 2017 @06:48AM (#14890825)

It is no different from using a code generator for anything. Json2elm is designed to _help you_ write decoders, not replace decoders. Once you know how to write them, json2elm is mostly useful for generating boilerplate.

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Re:Elm in Production: 25K Lines Later by dmitriid on Monday July 31, 2017 @07:13AM (#14890901)

If you need a code generator to generate boilerplate... something's wrong with your language

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Re:Elm in Production: 25K Lines Later by ch4s3 on Monday July 31, 2017 @08:22AM (#14891237)

I suppose you start every new project with mkdir and a few touch commands?

In all seriousness, ever language has boilerplate. In js it might be error handling and state management. In Elm, its decoding json.

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Re:Elm in Production: 25K Lines Later by dmitriid on Monday July 31, 2017 @08:40AM (#14891347)

> I suppose you start every new project with mkdir and a few touch commands?

This is not a valid analogy (and no analogy is ever valid).

> In js it might be error handling and state management. In Elm, its decoding json.

Yeah, and Go has trouble with generics.

It doesn't mean it's a feature that has to be vigorously defended. Especially if it's basically the very first thing anyone will have to do in any web application in a language that is meant for client-side web programming

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Re:Elm in Production: 25K Lines Later by ch4s3 on Monday July 31, 2017 @09:58AM (#14891993)

> It doesn't mean it's a feature that has to be vigorously defended.

I'm not sure anyone is defending it. At least, I'm not. Basically Elm's compromise is safety, and less runtime complexity then Haskell. The trade off there is boilerplate. As with most things, there is no free lunch. I've stopped using Elm precisely because of these issues, but I understand why Evan made the choices he did.

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Re:Elm in Production: 25K Lines Later by KirinDave on Monday July 31, 2017 @04:36PM (#14895682)

So... you don't use yo/yeoman? At all?

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