Checking environment objects for use in grade_this()

Source: R/grade_this.R

grade_this() allows instructors to determine a grade and to create custom feedback messages using custom R code. To facilitate evaluating the exercise, grade_this() makes available a number of objects that can be referenced within the { ... } expression.

All of the objects provided by learnr to an exercise checking function are available for inspection. To avoid name collisions with user or instructor code, the names of these objects all start with ..

  • .label: The exercise label.

  • .engine: The exercise engine, typically 'r'.

  • .last_value: The last value returned from evaluating the user's exercise submission.

  • .solution_code: A string containing the code provided within the *-solution chunk for the exercise.

  • .user_code: A string containing the code submitted by the user.

  • .check_code: A string containing the code provided within the *-check or *-code-check chunk for the exercise.

  • .envir_prep: A copy of the R environment after running the exercise setup code and before the execution of the student's submitted code.

  • .envir_result: The R environemnt after running the student's submitted code.

  • .evaluate_result: The return value from the evaluate::evaluate() function (see learnr's documentation).

In addition, gradethis has provided some extra objects:

  • .user, .result: The last value returned from evaluating the user's exercise submission.

  • .solution: The last value returned from evaluating the .solution_code for the exercise (evaluated in .envir_prep).

.result

.user

.last_value

.solution

.user_code

.solution_code

.envir_prep

.envir_result

.evaluate_result

.label

.engine

Format

An object of class .result (inherits from gradethis_placeholder) of length 0.

An object of class .user (inherits from .result, gradethis_placeholder) of length 0.

An object of class .last_value (inherits from .result, gradethis_placeholder) of length 0.

An object of class .solution (inherits from gradethis_placeholder) of length 0.

An object of class .user_code (inherits from gradethis_placeholder) of length 0.

An object of class .solution_code (inherits from gradethis_placeholder) of length 0.

An object of class .envir_prep (inherits from gradethis_placeholder) of length 0.

An object of class .envir_result (inherits from gradethis_placeholder) of length 0.

An object of class .evaluate_result (inherits from gradethis_placeholder) of length 0.

An object of class .label (inherits from gradethis_placeholder) of length 0.

An object of class .engine (inherits from gradethis_placeholder) of length 0.