adding syntax highlighting to Jupyter notebook cell magic

Question

I'm trying to figure out how to activate CodeMirror syntax highlighting for a CodeMirror-supported language (cypher) within a cell for a custom Jupyter cell magic (%%mymagic). The magic isn't associated with a special kernel - it just runs Python commands that process the string entered into the cell that I want to highlight. From what I can tell, this ostensibly can be done using something like

from notebook.services.config.manager import ConfigManager
cm = ConfigManager()
cm.update('notebook', {'CodeCell': {'highlight_modes': {'magic_cypher': {'reg': '^%%mymagic'}}}})

within the class that implements the magic. I can't seem to get this to work, however; no change in highlighting occurs when I enter stuff in a cell that starts with %%mymagic. Is the above approach accurate? Does 'magic_cypher' need to have a specific format? Does the magic need to somehow specify the MIME type CodeMirror associates with the desired highlighting language? I'm using notebook 5.0.0, jupyter_core 4.3.0, and python 2.7.13.

Answer 1

The following code works for SQL when placed in ~/.jupyter/custom/custom.js with notebook 5.x:

require(['notebook/js/codecell'], function(codecell) {
  codecell.CodeCell.options_default.highlight_modes['magic_text/x-mssql'] = {'reg':[/^%%sql/]} ;
  Jupyter.notebook.events.one('kernel_ready.Kernel', function(){
  Jupyter.notebook.get_cells().map(function(cell){
      if (cell.cell_type == 'code'){ cell.auto_highlight(); } }) ;
  });
});

Credit goes to Thomas K for this info!