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Scala 3.0.0-M1

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Re: Scala 3.0.0-M1

#121

Post by sireat »

smabie wrote: post #4

I've always loved Scala and Scala 3 is shaping up to be extremely exciting. Love the new ADTs and braceless syntax: really gives the language a cleaner and more ML inspired feel. No other conventional language (including OCaml, F#, etc) seem to have the effortless kind of power Scala does. The combination of the extremely powerful type system with the "OOFP" paradigm is a great combination. OOFP is such a great parad…

When Scala, IntelliJ and SBT cooperate the language is so pleasant to work with.

There are some puzzling omissions though.

For example slice method is missing step. Coming from heavy data munging Python this really bites. Sure would be nice to have some syntactic sugar for slice.

Some seemingly simple tasks have no one way of solving them.

Let's take parsing JSON. Trivial in Python, painful in Scala. (almost the reverse in Python which has painful XML parsing and Scala's built in support for XML)

So far the easiest JSON library has been Li Haoyi's uPickle: https://www.lihaoyi.com/post/HowtoworkwithJSONinScala.html

Still, it does not parse JSON where objects have uknown arbitrary value types. Arbitrary value types are extremely common in real life JSON.

Due to pattern matching you see people suggesting you write your own parser! Sure it can be done, but then the next thing you'll be rolling your own crypto...

Re: Scala 3.0.0-M1

#122

Post by sjrd »

sireat wrote: post #121
smabie wrote: post #4

I've always loved Scala and Scala 3 is shaping up to be extremely exciting. Love the new ADTs and braceless syntax: really gives the language a cleaner and more ML inspired feel. No other conventional language (including OCaml, F#, etc) seem to have the effortless kind of power Scala does. The combination of the extremely powerful type system with the "OOFP" paradigm is a great combination. OOFP is such a great parad…

When Scala, IntelliJ and SBT cooperate the language is so pleasant to work with. There are some puzzling omissions though. For example slice method is missing step. Coming from heavy data munging Python this really bites. Sure would be nice to have some syntactic sugar for slice. Some seemingly simple tasks have no one way of solving them. Let's take parsing JSON. Trivial in Python, painful in Scala. (almost the reve…

> So far the easiest JSON library has been Li Haoyi's uPickle: https://www.lihaoyi.com/post/HowtoworkwithJSONinScala.html

> Still, it does not parse JSON where objects have uknown arbitrary value types. Arbitrary value types are extremely common in real life JSON.

Looks like ujson, which the article you point to talks about, is what you're looking for. uPickle is a layer on top of ujson for statically typed stuff, but ujson is working with raw JSON values, of arbitrary types.

Re: Scala 3.0.0-M1

#123

Post by ph2082 »

I have downloaded this big open source project which uses spring and ibatis and have everything which OOP offers.

For learning Scala, I am trying to re-write it using play framework. Case classes do offer reduction in boiler plate code. But write now feeling overwhelmed about how to map all this deep inheritance tree, factories etc. from OOP world to functional way of doing things.

I hope someone write side by side mapping of doing things in Scala 2 vs Scala 3.

Re: Scala 3.0.0-M1

#124

Post by ph2082 »

esarbe wrote: post #105
tastyminerals2 wrote: post #72

Earlier quoted context omitted.

There is no straighforward elegant way of doing "obj.scalaMethod.myCustomMethod.scalaMethod.myCustomMethod" in Scala. I want to create a method and just inject it into the chain, no fiddling or ducktaping or using some black Scala magic. "def myFun(a: String, b: Double): Boolean = {...}" and then "obj.mapValues.myFun.forall(_)" or just anything similar. And yes, Scala is exactly the language when you need safe and ma…

In the Scala 2.x this can be done with an implicit class. It's a bit cumbersome and not very use-case oriented (mechanism over intention) and so Scala 3 has introduced extension methods[0]. This gives you exactly what you want. Since Scala 3 is pretty much completely backwards compatible (and with the use of Tasty you can use Scala 3 code in Scala 2.x projects), so I don't see the migration as a big problem. The Scal…

Thank you for URL. Just when I needed. Any idea when "Scala 3" can be production ready ?

Re: Scala 3.0.0-M1

#125

Post by sireat »

sjrd wrote: post #122
sireat wrote: post #121

Earlier quoted context omitted.

When Scala, IntelliJ and SBT cooperate the language is so pleasant to work with. There are some puzzling omissions though. For example slice method is missing step. Coming from heavy data munging Python this really bites. Sure would be nice to have some syntactic sugar for slice. Some seemingly simple tasks have no one way of solving them. Let's take parsing JSON. Trivial in Python, painful in Scala. (almost the reve…

> So far the easiest JSON library has been Li Haoyi's uPickle: https://www.lihaoyi.com/post/HowtoworkwithJSONinScala.html > Still, it does not parse JSON where objects have uknown arbitrary value types. Arbitrary value types are extremely common in real life JSON. Looks like ujson, which the article you point to talks about, is what you're looking for. uPickle is a layer on top of ujson for statically typed stuff, bu…

Thank you! I will have to look into ujson deeper.

Re: Scala 3.0.0-M1

#126

Post by tastyminerals2 »

hocuspocus wrote: post #91
tastyminerals2 wrote: post #63

Earlier quoted context omitted.

Scala is weird. Sometimes it feels fluid and effortless but sometimes it simply cannot do things you would expect it to. For example, chaining custom methods. Why is it possible to do "arr.map(_.nonEmpty).filter(a => a % 2)" but not possible "arr.map(_.nonEmpty).myCustomFilter(_)"? In D thanks to UFCS and Properties you can chain all kinds of std and custom stuff together which looks more "efforless" and FP in my eye…

> Rust which simply has a wider applicability area Rust is a great language but that's a pretty insane statement. The ecosystem is still tiny compared to the JVM.

Out of context yes. I should have said that with respect to which language pick up next and which language has a bigger future potential. Rust is so omnivore and hits on so many critical aspects that it is hard to deny it. Given it had rich and mature ecosystem now how many would pick Scala? Those who prefer GC pauses and have a hard dependency on JVM? But even then you are pitted against Kotlin and Java itself. I would say quite tough times are awaiting Scala 3 and not only on individual level but on company level. It is still unclear how much the migration will take and whether it is worth it in the first place.

Re: Scala 3.0.0-M1

#127

Post by esarbe »

ph2082 wrote: post #124
esarbe wrote: post #105

Earlier quoted context omitted.

In the Scala 2.x this can be done with an implicit class. It's a bit cumbersome and not very use-case oriented (mechanism over intention) and so Scala 3 has introduced extension methods[0]. This gives you exactly what you want. Since Scala 3 is pretty much completely backwards compatible (and with the use of Tasty you can use Scala 3 code in Scala 2.x projects), so I don't see the migration as a big problem. The Scal…

Thank you for URL. Just when I needed. Any idea when "Scala 3" can be production ready ?

From what I saw in the latest presentation by Martin, we can expect Scala 3 to be released in late Spring/early Summer 2021.

Part of the release testing is building the community release[0], which is a large part of the relevant Scala F/OSS code out there.

Whether you consider that to be production ready you have to decide for yourself, I myself am pretty happy about it.

Keep in mind that for now Scala 2 style code will still be compiled and you can use existing Scala 2 code in your Scala 3 project. The migration should be pretty smooth.

[0] https://github.com/scala/community-build

Re: Scala 3.0.0-M1

#128

Post by esarbe »

haspok wrote: post #104
pkolaczk wrote: post #97

Earlier quoted context omitted.

Rust is a great language, and Scala is a great language, but they are different. They optimize for a different thing. Rust definitely rocks at high-performance, resource management, fine grained control over all the aspects of the program, at the expense of developer's time. Scala rocks at developer productivity and building abstractions, sacrificing a bit of performance. However, I must say that Rust is also a very…

> Scala is limited mostly to JVM... No, it's not. You can call native (C) functions from the JVM.

You still need a JVM, which what the GP is trying to point out (I think...)

That said; nowadays you have the Native and JS runtimes as possible targets as well. Scala.js works surprisingly good with very few caveats.

Re: Scala 3.0.0-M1

#129

Post by lihaoyi »

sireat wrote: post #125
sjrd wrote: post #122

Earlier quoted context omitted.

> So far the easiest JSON library has been Li Haoyi's uPickle: https://www.lihaoyi.com/post/HowtoworkwithJSONinScala.html > Still, it does not parse JSON where objects have uknown arbitrary value types. Arbitrary value types are extremely common in real life JSON. Looks like ujson, which the article you point to talks about, is what you're looking for. uPickle is a layer on top of ujson for statically typed stuff, bu…

Thank you! I will have to look into ujson deeper.

You can in fact mix typed and untyped parsing, by having a `ujson.Value` field in the middle of your typed case class or collection. It just works

Re: Scala 3.0.0-M1

#130

Post by esarbe »

TeeWEE wrote: post #7
smabie wrote: post #4

I've always loved Scala and Scala 3 is shaping up to be extremely exciting. Love the new ADTs and braceless syntax: really gives the language a cleaner and more ML inspired feel. No other conventional language (including OCaml, F#, etc) seem to have the effortless kind of power Scala does. The combination of the extremely powerful type system with the "OOFP" paradigm is a great combination. OOFP is such a great parad…

For me scala's feature set is absurdly big and there are always 10 ways todo things. Look at the spec of Scala. Its 200 pages long. That's insane. I'd rather use Kotlin.

Scala 3 tries to be more opinionated and goes quite some miles (kilometers?) to make the language more regular and simple.

The implicits are gone, for example. Kinda crazy, since it was Scala's banner feature for so long. For the primary use-cases of implicits (extensions, type classes, conversion, ...) there are now language level concepts to make these use-cases accessible.

"Intent over mechanism" I think Martin calls it.

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