AnswerTests             Answer Tests
InstallCourses          Installing Courses
any_of_exprs            Test that the user has entered one of several
                        possible expressions.
bye                     Exit swirl.
calculates_same_value   Test that the user's expression evaluates to a
                        certain value.
delete_progress         Delete a user's progress
email_admin             Send diagnostic email to swirl admin
expr_creates_var        Test that a new variable has been created.
expr_identical_to       Test that the user has entered a particular
                        expression.
expr_is_a               Test that the expression itself is of a
                        specific 'class'.
expr_uses_func          Test that a particular function has been used.
func_of_newvar_equals   Test the result of a computation applied to a
                        specific (user-named) variable created in a
                        previous question.
info                    Display a list of special commands.
install_course          Install a course from The swirl Course Network
                        or install a course from a local .swc file.
install_course_directory
                        Install a course from a course directory
install_course_dropbox
                        Install a course from a zipped course directory
                        shared on Dropbox
install_course_github   Install a course from a GitHub repository
install_course_google_drive
                        Install a course from a zipped course directory
                        shared on Google Drive
install_course_url      Install a course from a url that points to a
                        zip file
install_course_zip      Install a course from a zipped course folder
install_from_swirl      Install a course from the official course
                        repository
is_robust_match         Recursively expand both the correct expression
                        and the user's expression and test for a match.
                        CAUTION: May raise errors, as in rmatch_calls.
main                    Return to swirl's main menu.
nxt                     Begin the upcoming question or unit of
                        instruction.
omnitest                Test for a correct expression, a correct value,
                        or both.
play                    Tell swirl to ignore console input for a while.
reset                   Start over on the current script question.
restart                 Restart the current swirl lesson.
rmatch_calls            Recursively expand match calls in an expression
                        from the bottom up.
select_language         Select a language
skip                    Skip the current unit of instruction.
submit                  Submit the active R script in response to a
                        question.
swirl                   An interactive learning environment for R and
                        statistics.
swirl_options           Get swirl options
uninstall_all_courses   Uninstall all courses
uninstall_course        Uninstall a course
val_has_length          Test that the value of the expression has a
                        particular 'length'.
val_matches             Test that the user's expression matches a
                        regular expression.
var_is_a                Test that the value of the expression is of a
                        specific class.
zip_course              Zip a course directory
