8 ms·

So...what would be needed to see native Haskell iOS apps? :)

by james4k 14y ago

eru 14y ago
Doesn't Apple still forbid programs written in anything apart from Objective C, JavaScript (and a third language, that I don't remember)?
- krevis 14y ago
  The guidelines say nothing about any particular programming languages.
- franzus 14y ago
  No.
- cantankerous 14y ago
  Knowing the Haskell community, they could probably convert GHC Core into idiomatic Objective-C if they really wanted to, but it's not necessary. RubyMotion and other platforms are accepted because they stick to Apple's guidelines. The same would go for a GHC-iPhone platform. iPhone Monad, anyone?
  - danieldk 14y ago
    Why would one need to, GHC can already compile Haskell/Core to C? But as you say, it's not a violation of Apple's terms anymore.
    - cantankerous 14y ago
      Because compiling to C would be too easy.
- ryannielsen 14y ago
  Nope, not anymore. http://daringfireball.net/2010/09/app_store_guidelines http://daringfireball.net/2010/09/app_store_guidelines
- shriphani 14y ago
  You can always compile scheme / haskell etc to C and then use it as a library. (gambit-scheme users do this).
  - danieldk 14y ago
    Indeed. I did this with one program: I wrote some number crunching code in Haskell, and exposed some functions to C via the FFI. Then I wrote the user interface in Cocoa/Objective-C. The primary thing that requires some though is how to pass data between C and Haskell. You usually end up marshaling/unmarshaling some structs: http://www.haskell.org/haskellwiki/FFICookBook#Working_with_structs http://www.haskell.org/haskellwiki/FFICookBook#Working_with_...
    - Dn_Ab 14y ago
      Sounds quite interesting. Do you have a write up about this anywhere? Is the gain rom Haskell worth the impedance mismatch of cross communication?
      - danieldk 14y ago
        Do you have a write up about this anywhere? I used the following references: http://www.haskell.org/ghc/docs/7.4.1/html/users_guide/ffi-ghc.html http://www.haskell.org/ghc/docs/7.4.1/html/users_guide/ffi-g... http://weblog.haskell.cz/pivnik/building-a-shared-library-in-haskell/ http://weblog.haskell.cz/pivnik/building-a-shared-library-in... I have just put up a small-ish example using my approx-rand-test package (which implements approximate randomization tests): https://github.com/danieldk/haskell-library-example/ https://github.com/danieldk/haskell-library-example/ Is the gain rom Haskell worth the impedance mismatch of cross communication? I guess it depends on how much you love Haskell ;), and the usage scenario. I think using Haskell's FFI in this direction is especially attractive if you prefer to write most code in Haskell, but need some functionality that does not map naturally to a pure functional language (such as GUIs in Cocoa). If you want to mix a lot of imperative and functional code seamlessly, F#/C# or Scala/Java are probably better options.
Dn_Ab 14y ago
Saw this recently. https://github.com/ghc-ios/ghc/wiki https://github.com/ghc-ios/ghc/wiki It looks like there is no prebuilt package of interfaces with iOS so still a ways to go. Still great work though.
T_S_ 14y ago
Cross compilation is not yet supported. You want to build on osx/intel and target ios/arm. Not yet. ghc still needs to target the platform it was built on.

So...what would be needed to see native Haskell iOS apps? :)

by james4k 14y ago

So...what would be needed to see native Haskell iOS apps? :)

eru 14y ago

Doesn't Apple still forbid programs written in anything apart from Objective C, JavaScript (and a third language, that I don't remember)?

krevis 14y ago
The guidelines say nothing about any particular programming languages.
franzus 14y ago
No.
cantankerous 14y ago
Knowing the Haskell community, they could probably convert GHC Core into idiomatic Objective-C if they really wanted to, but it's not necessary. RubyMotion and other platforms are accepted because they stick to Apple's guidelines. The same would go for a GHC-iPhone platform. iPhone Monad, anyone?
- danieldk 14y ago
  Why would one need to, GHC can already compile Haskell/Core to C? But as you say, it's not a violation of Apple's terms anymore.
  - cantankerous 14y ago
    Because compiling to C would be too easy.
ryannielsen 14y ago
Nope, not anymore. http://daringfireball.net/2010/09/app_store_guidelines http://daringfireball.net/2010/09/app_store_guidelines
shriphani 14y ago
You can always compile scheme / haskell etc to C and then use it as a library. (gambit-scheme users do this).
- danieldk 14y ago
  Indeed. I did this with one program: I wrote some number crunching code in Haskell, and exposed some functions to C via the FFI. Then I wrote the user interface in Cocoa/Objective-C. The primary thing that requires some though is how to pass data between C and Haskell. You usually end up marshaling/unmarshaling some structs: http://www.haskell.org/haskellwiki/FFICookBook#Working_with_structs http://www.haskell.org/haskellwiki/FFICookBook#Working_with_...
  - Dn_Ab 14y ago
    Sounds quite interesting. Do you have a write up about this anywhere? Is the gain rom Haskell worth the impedance mismatch of cross communication?
    - danieldk 14y ago
      Do you have a write up about this anywhere? I used the following references: http://www.haskell.org/ghc/docs/7.4.1/html/users_guide/ffi-ghc.html http://www.haskell.org/ghc/docs/7.4.1/html/users_guide/ffi-g... http://weblog.haskell.cz/pivnik/building-a-shared-library-in-haskell/ http://weblog.haskell.cz/pivnik/building-a-shared-library-in... I have just put up a small-ish example using my approx-rand-test package (which implements approximate randomization tests): https://github.com/danieldk/haskell-library-example/ https://github.com/danieldk/haskell-library-example/ Is the gain rom Haskell worth the impedance mismatch of cross communication? I guess it depends on how much you love Haskell ;), and the usage scenario. I think using Haskell's FFI in this direction is especially attractive if you prefer to write most code in Haskell, but need some functionality that does not map naturally to a pure functional language (such as GUIs in Cocoa). If you want to mix a lot of imperative and functional code seamlessly, F#/C# or Scala/Java are probably better options.

Dn_Ab 14y ago

Saw this recently. https://github.com/ghc-ios/ghc/wiki https://github.com/ghc-ios/ghc/wiki It looks like there is no prebuilt package of interfaces with iOS so still a ways to go. Still great work though.

T_S_ 14y ago

Cross compilation is not yet supported. You want to build on osx/intel and target ios/arm. Not yet. ghc still needs to target the platform it was built on.