Create options for users when used in question_checkbox() and question_radio() learnr questions. For question_text() and question_numeric(), the individual answers aren't directly presented to students, but their values can be used in determining if the student submitted the correct answer. For flexible feedback from checkbox, text, and numeric questions, answer_fn() can be used to provide a function that evaluates the student's submission and returns a custom result.

## Usage

answer(text, correct = FALSE, message = NULL, label = text)

answer_fn(fn, label = NULL)

## Arguments

text

The answer text or value; for selection-type questions this value is shown to the user.

correct

Logical value indicating whether the answer() corresponds to a correct or incorrect option.

message

A custom message shown when this answer is selected and when the overall question result matches the state of this answer. For example, the message of a correct solution is not shown when the entire submission is incorrect, but will be shown when the user both picks this answer option and the question is correct.

label

The label shown when the option is presented to the user.

fn

A function used to evaluate the submitted answer. The function is called with the student's submitted value as the first argument, so the function should take at least one argument where the user's value will be passed to the first argument. Inline purrr-style lambda functions are allowed, see rlang::as_function() for complete details on the syntax.

In the body of the function, you can perform arbitrary calculations to decide if the submitted answer is or is not correct and to compose the message presented to the user. To signal a final answer, call mark_as() or its helper functions correct() or incorrect(). All other return values are ignored; e.g. by returning NULL you may yield the submission evaluation to other answer() or answer_fn() options for the question.

## Value

Returns a list with the "tutorial_question_answer" class.

## Functions

• answer: Create an answer option

• answer_fn: Evaluate the student's submission to determine correctness and to return feedback.