Extension for template-based practice problems

[gdancik]

This pull request includes three changes:

Addition of template-based practice problems (currently described at https://github.com/gdancik/swirl-tbp), which allows instructors to specify question templates where values and other components are dynamically generated when the lesson is run.

Addition of a rpt() function that allows a user to repeat the previous question or a similar question if values are dynamically generated.

For each question, a HintFunction can be specified, which is the name of a function (provided in initLesson.R) that will be called when the user's response is not correct. This allows for more advanced hints (such as those including graphics) and hints that can be tailored based on the user's response.

An example lesson can be found here: https://github.com/gdancik/swirl-tbp/tree/swirl-tbp_example

From within R, install the lesson by typing
install_course_github("gdancik", "swirl-tbp", "swirl-tbp_example")

[seankross]

Hi Garrett,

I sincerely like all of these ideas but I honestly won't have the time to review your code with the required level of detail necessary until after New Years. Sorry for the delay.

Sean

[gdancik]

Hi Sean,

No problem... I understand how busy things can get, especially this time of year. When you do have a chance to look at the code, don't hesitate to contact me if you have any questions. I've started using this extension in one of my courses this semester and hope to do a lot more with it in the same class next Fall.

• Garrett