IHaskell is an implementation of the IPython kernel protocol which allows you to use Haskell inside IPython frontends such as
The project works with the IPython shell:
As well as the IPython browser-based notebook interface:
More usage information on the wiki.
IHaskell uses a library known as ZeroMQ for asynchronous communication. Make sure that ZeroMQ 4 is installed - it is a relatively recent library and thus you may have older versions installed.
For Macs, you can easily install it with Homebrew:
# For Macs with Homebrew: brew update brew install zeromq
On other platforms, you can easily install from source:
# Compiling from source: git clone email@example.com:zeromq/zeromq4-x.git libzmq cd libzmq ./autogen.sh && ./configure && make sudo make install sudo ldconfig
If your own platform has a package and I haven't included instructions for it, feel free to send me an email or a PR on this README.
You should also have GHC and modern Cabal:
ghc --numeric-version # Should be 7.6.3 cabal --version # Should be 1.18.*
Since IHaskell uses the GHC API for evaluation and parsing, other versions of GHC may not work.
If you do not have GHC or Cabal, you should be able to install both via the Haskell Platform. On Macs with Homebrew, you can do this via
# Macs with Homebrew only, if you don't have GHC or Cabal brew install haskell-platform cabal update && cabal install cabal-install
cabal install cabal-install to update Cabal if you still have version 1.16 instead of 1.18.
Also, in order to use executables which
cabal installs, they must be in your path. Execute this in your shell or add it to your
# If you have a ~/.cabal/bin folder: export PATH=~/.cabal/bin:$PATH # If you have a ~/Library/Haskell/bin folder on OS X: export PATH=~/Library/Haskell/bin:$PATH
happy parser generator tool and
cabal install happy cpphs
Install the IHaskell package from Hackage:
cabal install ihaskell
Finally, run the notebook or console interface:
IHaskell notebook # Should open a browser window! IHaskell console
There is a test notebook in the
IHaskell directory. To try it, run IHaskell with
IHaskell notebook --serve=IHaskell.
Note: You may have some trouble due to browser caches with the notebook interface if you also use IPython's notebook interface or have used it in the past. If something doesn't work or IPython says it can't connect to the notebook server, make sure to clear the browser cache in whatever browser you're using, or try another browser.
IHaskell is a young project, and I'd love your help getting it to a stable and useful point. There's a lot to do, and if you'd like to contribute, feel free to get in touch with me via my email at andrew period gibiansky at gmail - although browsing the code should be enough to get you started, I'm more than happy to answer any questions myself.
For package maintainers: IHaskell has an ability to display data types it knows about with a rich format based on images or HTML. In order to do so, an external package
ihaskell-something must be created and installed. Writing these packages is simply - they must just contain instance of the
IHaskellDisplay typeclass, defined in
IHaskell.Display, and for a package
ihaskell-something should have a single module
IHaskell.Display.Something. If you have a package with interesting data types that would benefit from a rich display format, please get in contact with me (andrew dot gibiansky at gmail) to write one of these packages! A sample package is available here.
Skim the rather-lacking Haddock documentation.
Main: Argument parsing and basic messaging loop, using Haskell Chans to communicate with the ZeroMQ sockets.
IHaskell.Types: All message type definitions.
IHaskell.Eval.Evaluate: Wrapper around GHC API, exposing a single
evaluateinterface that runs a statement, declaration, import, or directive.
IHaskell.IPython: Shell scripting wrapper using
IHaskell.Message.Parser: Parsing messages received from IPython.
IHaskell.Message.UUID: UUID generator and data structure.
IHaskell.ZeroMQ: Low-level ZeroMQ communication wrapper.
serveProfilestarts listening on all necessary sockets, and returns a
ZeroMQInterfacerecord. This record exposes reading and writing
Chan Messagemessages for all the necessary sockets, so then the rest of the application can simply use that interface.
- Fork the repository on Github and clone your fork for editing.
- Build IHaskell as follows:
cd /path/to/IHaskell cabal configure --enable-tests cabal build
Loading IHaskell into GHCi for testing:
Use one of the methods below to access IHaskell files in GHCi. Once inside GHCi, you can load an IHaskell file; for example,
Using cabal repl
If you have the latest version of cabal (>v1.18.0), the simplest thing to do is
cd <path-to-IHaskell> cabal repl
The will hide all packages not listed in the
Using GHCi directly
If you don't want to use
cabal repl, you can just call ghci which can read the
.ghci file included in the repository for the options.
cd <path-to-IHaskell> chmod 600 .ghci # trust the .ghci file ghci
Then in the ghci session you can type things like:
:load src/Hspec.hs hspec parserTests :browse IHaskell.Types