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Frege – a Haskell for the JVM

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Re: Frege – a Haskell for the JVM

#21

Post by agumonkey »

ww520 wrote: post #18
georgewsinger wrote: post #7

One of the weaknesses of Clojure on the JVM is its ridiculously long startup time. How fast does Frege start up on the JVM?

Clojure is slow at startup because of the long list of classes have to be loaded at init I think.

It's the core namespace that is huge. Also clojure embeds all metadata etc, taking more time than necessary for a script runtime. Clojure guys discussed having multiple builds, a lean runtime for fast boot, and more featured one for repl usage (even more documentation embedded etc)

Re: Frege – a Haskell for the JVM

#22

Post by voxfrege »

mike_hearn wrote: post #17
voxfrege wrote: post #12

Earlier quoted context omitted.

It's okay, at least when you have SSD or at least decent RAM. Here is an example: ingo@freguntu:~/Frege/frege$ time java -jar fregec.jar -version 3.23.900 0:00.22 62016k ingo@freguntu:~/Frege/frege$ ls -l fregec.jar -rw------- 1 ingo ingo 33426802 Mär 6 12:32 fregec.jar

Aren't you checking the Frege compiler, there? The complaint about Clojure is that Clojure apps start slow. Frege compiles to Java and from there to bytecode, so you'd need to compare a hello world in both languages to answer the original question, I think.

The compiler is a Frege app.

Re: Frege – a Haskell for the JVM

#23

Post by voxfrege »

mrcactu5 wrote: post #19

Last I checked it was not possible to use a Frege program on Android. Has that changed any? http://stackoverflow.com/questions/17222383/how-to-run-frege... http://stackoverflow.com/questions/5151858/running-a-haskell...

The demand seems to be not that big, at least nobody started to seriously take on some out of the box Android support.

Re: Frege – a Haskell for the JVM

#25

Post by dudul »

brianberns wrote: post #24

Are typeclasses possible on the JVM? I'm a .NET person, and I've always heard that typclasses aren't possible on the .NET CLR, so I wonder what's different about the JVM that makes this possible?

Scala has typeclasses. It is not strictly equal to Haskell since it relies on the usage of `implicit`. Plus it doesn't enforce that there is only one typeclass per type in the classpath (I believe I remember that Haskell enforces that I compile time).

Re: Frege – a Haskell for the JVM

#26

Post by voxfrege »

brianberns wrote: post #24

Are typeclasses possible on the JVM? I'm a .NET person, and I've always heard that typclasses aren't possible on the .NET CLR, so I wonder what's different about the JVM that makes this possible?

Frege has typeclasses (Haskell 2010).

Whoever told you it's impossible in .NET is probably wrong. Don't you have interfaces in C# ? But you don't even need interfaces. Strictly speaking, unless you use typeclasses with polymorphic recursion, you don't need a runtime representation for typeclasses at all.

Re: Frege – a Haskell for the JVM

#27

Post by voxfrege »

mark_l_watson wrote: post #15

I need to take a serious look at Frege. I am writing a book on Haskell and I have spent years using various JVM languages, so Frege seems like a good bet to invest some time on - if the development environment, REPL style Dev, etc. is as smooth as it is for Haskell.

I can only encourage you to do this, and come back with criticism (or praise).

Re: Frege – a Haskell for the JVM

#28

Post by voxfrege »

asplake wrote: post #11
nine_k wrote: post #10

Earlier quoted context omitted.

I fail to understand the question. Isn't hosting "pure" Haskell code in an imperative modern OS environment a common thing to do?

I mean leaving IO to a program to which the (pure-only) Haskell code is linked, dispensing with monad-based separation. Frege seems to make this particularly easy.

Sure, this would be possible.

You can call "into" Frege code from any JVM language. OTOH, you can call any JVM code you could with Java (Frege is compiled to Java source code).

The crucial point are the data that get exchanged between Frege and Java in either direction. While there are no problems with primitive types or Strings, standard JVM container classes like java.util.HashMap or java.util.ArrayList represent mutable data, and thus we can't use them with _pure_ Frege code.

For that reason, we still need monads (in particuar, IO and ST) to deal with mutable data in Frege.

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