Feature request: pre-checking of code

[dtkaplan]

The student's submitted code is evaluated before handing it off to the checker function. This makes sense, but when the evaluation fails, the student gets feedback from R rather than from the checking code.

Might it be arranged to send the code to a pre-evaluation checking chunk. Then the checking system can have at it before R. Feedback messages would be returned in the usual way. Only if the feedback is passing, should the code be evaluated. Then the evaluated code can be sent again to the checking system. Since the checking system knows specifically what the code should look like, it can perhaps identify problems that don't produce helpful errors from R.

[jjallaire]

Yes, will add this as well (may take a couple of weeks due to various holiday obligations though!)

[jjallaire]

Fixed here: 0fc1ff2

Docs here: https://rstudio.github.io/tutor/45796A4F836C4B5B/exercises.html#code-checking