Cannot load codemirror mode dynamically

[BoPeng]

The following patch load mode only when they are needed. It is supposed to work but somehow does not.

diff --git a/src/sos_notebook/kernel.js b/src/sos_notebook/kernel.js
index e5d340c..5b7165a 100644
--- a/src/sos_notebook/kernel.js
+++ b/src/sos_notebook/kernel.js
@@ -25,13 +25,7 @@ define([
     "codemirror/lib/codemirror",
     "codemirror/mode/python/python",
     "codemirror/mode/r/r",
-    "codemirror/mode/octave/octave",
-    "codemirror/mode/ruby/ruby",
-    "codemirror/mode/sas/sas",
-    "codemirror/mode/javascript/javascript",
-    "codemirror/mode/shell/shell",
-    "codemirror/mode/julia/julia",
-    "codemirror/mode/markdown/markdown",
+    'codemirror/lib/util/loadmode',
     "codemirror/addon/selection/active-line",
     "codemirror/addon/fold/foldcode",
     "codemirror/addon/fold/foldgutter",
@@ -2100,6 +2094,7 @@ table.task_table {
 
             "use strict";
 
+            CodeMirror.modeURL = "codemirror/mode/%N/%N.js";
             var sosKeywords = ["input", "output", "depends", "parameter"];
             var sosActionWords = ["script", "download", "run", "bash", "sh", "csh",
                 "tcsh", "zsh", "python", "python2", "python3", "R", "node", "julia",
@@ -2252,7 +2247,7 @@ table.task_table {
                 if ('base_mode' in parserConf) {
                     let mode = findMode(parserConf.base_mode.toLowerCase());
                     if (mode) {
-                        base_mode = CodeMirror.getMode(conf, mode);
+                        base_mode = CodeMirror.loadMode(conf, mode);
                     } else {
                         console.log(`No base mode is found for ${parserConf.base_mode}. Python mode used.`);
                     }
@@ -2502,7 +2497,7 @@ table.task_table {
                                     let mode = findMode(state.sos_state.slice(6).toLowerCase());
                                     if (mode) {
                                         state.sos_state = null;
-                                        state.inner_mode = CodeMirror.getMode(conf, mode);
+                                        state.inner_mode = CodeMirror.loadMode(conf, mode);
                                         state.inner_state = CodeMirror.startState(state.inner_mode);
                                     } else {
                                         state.sos_state = 'nomanland';

[BoPeng]

Jupyter has (autoLoadMode)[https://github.com/jupyter/notebook/blob/master/notebook/static/notebook/js/cell.js#L642] here but it is not used.

[BoPeng]

If this can be fixed, we can not only remove most of the modes statically imported in here, but also lines in the template because the modes have to be statically imported to be used by the template, which also means we are limited to these langauges.