navigating cabal hell for iHaskell

README.md

How to Install iHaskell

iHaskell is a notebook similar to iPython notebook. Here's to hoping it will become easier to learn the very complix Haskell language.

you might need Python's virtual environments

• http://coldwa.st/e/blog/2013-08-20-Cabal-sandbox.html

I raised many Github issues and StackOverflow questions loudly expressing my grief on installation issues

• IHaskell/IHaskell#442
• ekmett/semigroupoids#21 ekmett/distributive#9

I will try to find some choice excerpts. In the end, Cabal sandbox allowed me to install IHaskell 0.5.0 with iPython 2 (not iPython 3 aka "Jupyter"). Then...

iHaskell merges 'Jupyter' branch

IHaskell did have support for Jupyter on Github (which is still ahead of Hackage), now it is merged into main.

Prerequisites

Install a recent version of Haskell. In my case, Ubuntu 14.04

• https://launchpad.net/~hvr/+archive/ubuntu/ghc

GHC is split into 4 packages,

ghc-$VER (core package, contains ghc and executables such as haddock) ghc-$VER-dyn (contains dynamic libraries; dummy package for GHC 7.8 and later) ghc-$VER-prof (contains profiling libs) ghc-$VER-htmldocs (contains generated HTML Haddock output)

The packages install into /opt/ghc/$VER/ so in order to use them, the easiest way is to bring a particular GHC version into scope by placing the respective /opt/ghc/$VER/bin folder early into the PATH environment variable.

Install a recent version of Cabal. In my case, cabal install cabal-install wasn't working properly. the ghc bash command was pointing to version 7.6.3 installed on a different part of my computer. And cabal pointed to an old version too.

• https://github.com/haskell/cabal/