Spec and implementation of markdown extensions

[gnestor]

There are many issues related to extending markdown to support different elements and use cases:

• Proper way to add "alert"/"note"/"hint"/"warning"/... boxes? #1292
• Feature Request: Enhanced Markdown Support For Graphs #2300
• Support asciimath in Markdown fields #1918
• missing markdown features: image size and colspan #1095
• Non-http URL schemes in Markdown cells #189
• Make markdown header ID and anchor ID unique #77
• Allow references to Python variables in Markdown cells ipython/ipython#2958

And an ongoing discussion about switching to Commonmark: Related to #1371

Let's bring these separate discussions together here and figure out a good way enable this in classic notebook, JupyterLab, nteract, nbconvert, nbviewer, etc.

cc @ellisonbg @Carreau @takluyver @rgbkrk @minrk @blink1073 @jasongrout

[gnestor]

There are also many issues related to spotty mathjax/LaTeX support in markdown:

• string in double $ will convert to MathJax when using pandas Dataframe #2444
• Mathjax with double dollar signs not rendered on notebook hosted on Github #1962
• Mathjax blocks are not highlighted correctly in 4.2.2 #1733
• markdown / mathjax - right bracket of big matrices moved to new line #764
• Latex spacing bug in HTML output  #392
• Print view: MathJax not invoked on displayed equations enclosed in $$...$$, if the latex source contains a minus at the start of a line #317
• Mathjax with double dollar signs not rendered on notebook hosted on Github #1962
• Markdown in Latex blocks is still active #1911
• Latex in Markdown tables not rendering correctly as HTML #1542
• export to pdf fails for markdown cells with figures #1525
• Dollar $ sign ($) triggers errors in Markdown highlighting, even when escaped #1080

[rgbkrk]

Thanks for compiling this together. It's downright overwhelming to deal with all these conflicting extensions.

[JamiesHQ]

this is awesome! cc'ing @mpacer

[ellisonbg]

Awesome! Thanks for pulling all of this together. The big challenge in all of this is that there are *millions* of notebooks already written. If we change the syntax from what is supported in the classic notebook (and lab), we will break those notebooks. Minimally, we would need a major version change to the notebook format... [ Another nice way of tracking lots of issues like this is to use a GitHub project, makes it easier to track dynamic sets of issues that aren't quite a milestone.]

…

On Thu, Apr 27, 2017 at 1:12 PM, JamieW ***@***.***> wrote: this is awesome! cc'ing @mpacer <https://github.com/mpacer> — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#2450 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AABr0PWCnhBMipLiSo0DGOrEdhK1GD2gks5r0Pa4gaJpZM4NKn6f> .

-- Brian E. Granger Associate Professor of Physics and Data Science Cal Poly State University, San Luis Obispo @ellisonbg on Twitter and GitHub bgranger@calpoly.edu and ellisonbg@gmail.com

[gnestor]

I don't think we want to introduce anything that breaks existing markdown in the notebooks, but rather provides an extension point for adding support for elements (e.g. to do lists, collapsible sections, "info" and "warn" boxes, AsciiMath, mermaid) or handling non-HTTP URLs.