notedown 1.1.0

Why?

Save yourself from the indignity of writing text in the browser!

There might be more reasons, but that was the main one for me.

Magic

Fenced code blocks annotated with a language other than python are read into cells using IPython’s %% cell magic.

You can disable this with --nomagic.

• --pre lets you add arbitrary code to the start of the notebook. e.g. notedown file.md --pre '%matplotlib inline' 'import numpy as np'

What notedown does not do:

• convert from notebook to markdown

• run code cells

• embed figures

Conversion from notebook to markdown

Converting from an IPython notebook to markdown is done using nbconvert:

ipython nbconvert notebook.ipynb --to markdown

The IPython markdown export is currently quite basic, so you can’t expect to convert markdown -> notebook -> markdown and get back your original markdown.

Running an IPython Notebook

You can open the notebook in your browser with

ipython notebook your_notebook.ipynb

and use Cell -> Run all in the menu.

You can run notebooks non-interactively from the command line using runipy:

pip install runipy
runipy your_notebook.ipynb

Or, if you’re using IPython 2.0:

ipython -c "%run your_notebook.ipynb"

This isn’t very interactive!

No, it isn’t. Notedown takes markdown and turns it into an IPython notebook.

You can set up a pseudo-interactive loop in Vim by calling

:!notedown % > out.ipynb

and viewing the result in the browser with

ipython notebook out.ipynb

You’ll get far better interactivity by using vim-ipython, which allows you to connect to a running ipython kernel. You can send code from vim to ipython and get code completion from the running kernel. Try it!

Here are some mappings for your vimrc to make this pleasant:

" Very useful mappings to be used with markdown and ipython
" search and select contents of fenced code blocks using <leader>f
nnoremap <leader>f /\v(\_^```python\n)@<=(\_.{-})(\n`{3}\_$)@=<CR>v//e<CR>
" goto the start of the current fenced code block with [b
" (see :help search)
nnoremap [b :call search('\n```python', 'b')<CR>
" select current code block with <leader>b
" TODO: assumes <leader>==, use <leader>f instead of ,f
" TODO: cancel search highlighting
nmap <leader>b [b,f
" (or could do [b0v/\n```)
" send current code block to ipython with <leader>p
nmap <leader>p ,b<C-s>

I can’t put a literal code block in my markdown!

Not right now, no. Notedown isn’t very clever.

Where’s my syntax highlighting?!

You can syntax highlight python code contained in fenced code blocks with this command (put it in your vimrc):

function! HiPy ()
    let b:current_syntax=''
    unlet b:current_syntax
    syntax include @py syntax/python.vim
    " github flavoured markdown (code blocks fenced with ```)
    syntax region gfmpythoncode keepend start="^```py.*$" end=/^\s*```$\n/ contains=@py
endfunction

" enable highlighting of fenced python code with <leader>h
map <leader>h :call HiPy ()<CR>

BONUS! Of course you can do the same for latex display and inline maths:

syntax include syntax/tex.vim
" display maths with $$ ... $$
syn region texdisplaymaths start="\$\$" end="\$\$" skip="\\\$" contains=@texMathZoneGroup
" inline maths with $ ... $
" start is a $ not preceded by another $        - \(\$\)\@<!\$
" and not preceded by a \ (concat)              - \(\$\)\@<!\&\(\\\)\@<!\$
" and not followed by another $                 - \$\(\$\)\@!
" ending in a $ not preceded by a \             - \((\$\)\@<!\$
" skipping any \$                               - \\\$
" see :help \@<! for more
syn region texinlinemaths start="\(\$\)\@<!\&\(\\\)\@<!\$\(\$\)\@!" end="\(\$\)\@<!\$" skip="\\\$" contains=@texMathZoneGroup
" restriction is that you can't have something like \$$maths$ - there
" has to be a space after all of the \$ (literal $)

TODO

• [x] support more markdowns

• [ ] allow other cell types?

• [x] allow different language code cells (using %%lang magic)

• [ ] allow code attributes? pass to cell creator?

• [x] code block format agnostic (fenced / indented)