Update IHaskell.IPython.EasyKernel.installKernelspec to use jupyter instead of ipython

[benrbray]

I wanted to run the Calc and Simple examples found in the ipython-kernel/examples folder, and noticed that the installKernelspec function is calling ipython kernelspec ... (an outdated way of doing it) instead of jupyter kernelspec ... (the new way).

IHaskell/ipython-kernel/src/IHaskell/IPython/EasyKernel.hs

Lines 94 to 116 in 8afa4e2

	-- Install the kernelspec, using the `writeKernelspec` field of the kernel configuration.
	installKernelspec :: MonadIO m
	=> KernelConfig m output result -- ^ Kernel configuration to install
	-> Bool -- ^ Whether to use Jupyter `--replace`
	-> Maybe FilePath -- ^ (Optional) prefix to install into for Jupyter `--prefix`
	-> m ()
	installKernelspec config replace installPrefixMay =
	liftIO $ withTmpDir $ \tmp -> do
	let kernelDir = tmp </> languageName (kernelLanguageInfo config)
	createDirectoryIfMissing True kernelDir
	kernelSpec <- writeKernelspec config kernelDir
	let filename = kernelDir </> "kernel.json"
	BL.writeFile filename $ encode $ toJSON kernelSpec
	let replaceFlag = ["--replace" | replace]
	installPrefixFlag = maybe ["--user"] (\prefix -> ["--prefix", prefix]) installPrefixMay
	cmd = concat [["kernelspec", "install"], installPrefixFlag, [kernelDir], replaceFlag]
	void $ rawSystem "ipython" cmd
	where
	withTmpDir act = do
	tmp <- getTemporaryDirectory
	withTempDirectory tmp "easyKernel" act

Error

As-is, I get the following error when attempting to install the simple-calc-example kernel:

ben@zagreus:~/oss/IHaskell/ipython-kernel$ cabal run simple-calc-example -- install
Resolving dependencies...
Up to date
Installing kernelspec...
[TerminalIPythonApp] WARNING | Unrecognized alias: 'user', it will have no effect.
[TerminalIPythonApp] WARNING | File 'kernelspec' doesn't exist

When I change the string "ipython" to "jupyter", the kernel installs without any issue and I'm able to open it from a running Jupyter notebook server.

Proposed Change

• call jupyter instead of ipython in installKernelspec and anywhere else the change is needed
• (optional) update comments / function / package names to reflect the split between Jupyter and IPython.
  • this is a breaking change to the package names, though, so understandable if the renaming is rejected
  • however, Jupyter has been separate from IPython since 2014, so perhaps it would be more clear if IHaskell reflected this change

References

• jupyter_client 8.0.3 docs, Making Kernels for Jupyter
• jupyter docs, Migrating from IPython Notebook (kernels section)

[vaibhavsagar]

I don't want to rename the packages, but your other proposed changes seem reasonable to me.