An interface for extensions to provide new part types.

It would be nice if it was possible to add new part types with extensions. As well as the code for the Numbas runtime, which I reckon you can already add, we also need code to display the part, which should belong to the theme, and a specification of an editing interface for the question editor to use. At the moment, part types in the editor are defined with by an object with a few settings: a name, a list of tabs, a knockout viewmodel, and functions to save and load to/from the question JSON format. Then there's a django template to render the corresponding HTML The only bits of that that I'm not comfortable with exposing publicly are the knockout viewmodel and the django template - both are very implementation-specific, and would cause a headache if I changed the way the editor works in future. A JSON format to specify just what the options are, without the ability to give any code to do anything clever with the UI, would at least allow a basic editor interface to be created in a fairly future-proof way. And if we're restricting the format of the options, then we can write generic code to load and save the part.

So, I imagine an extension package which adds a new part type would look like this:

myextension.js - code for the exam runtime
myextension.css - CSS for the exam runtime
myextension_part_types.json - specification of part types

myextension_part_types.json will look like the following:

[
    {
        name: 'mypart',
        niceName: 'My part type',
        has_marks: true,
        tabs: [
            {name: 'marking', niceName: 'marking', icon: 'pencil', fields: ['correctanswer','precision']},
            {name: 'extras1', niceName: 'Extra options 1', icon: 'asterisk', fields: ['magicword','requiremagicword']}
        ],
        fields: [
            {
                name: 'correctanswer',
                label: 'Correct answer',
                type: 'jme',
                show_preview: true,
                help_text: 'The answer the student should write'
            },
            {
                name: 'precision',
                label: 'Checking precision',
                type: 'number',
                min: 0,
                max: 100,
                help_text: "How accurate should the user's answer be, in microsmoots?"
            }
            {
                name: 'magicword',
                niceName: 'Magic word',
                type: 'string',
            },
            {
                name: 'requiremagicword',
                niceName: 'Require the magic word?',
                type: 'boolean',
                default: true
            }
        ]
    }
]

The editor would interpret this spec to create the relevant viewmodel and HTML, and the exam compiler and runtime would use it to create the XML/HTML representation of the part as well as the Numbas.Part class to actually run it.

numbas / editor

An interface for extensions to provide new part types. #291