Non-Ascii Characters should be reported

[JoshuaCapel]

Maple can break a string down into bytes, and the bytes can be used to detect non-ASCII characters.

The bytes could checked for unexpected characters, and appropriate advice given in the preview. This could also be reported in the gradebook as part of the newly developed feedback step, or used to attempt to turn the student input into standard ASCII.

Because of the multiple modes in which this information might be useful, a potentially good design pattern might be to have a function that takes a string (or byte sequence) as input and return an object containing the string/sequence broken up into sub-strings/sub-sequences with metadata (e.g. known non-ASCII characters with their ASCII equivalent).

This object can then be used to compose an appropriate message, or normalise the input as much as possible.