assert                  Display an error, and record in a log file, if
                        a condition is false
error                   Display an error, and record it in a log file.
error_if                Display an error, and record in a log file, if
                        a condition is true.
has_names               Checks whether the variable has names
info                    Display a message, and record it in a log file.
info_if                 Display a message, and record in a log file, if
                        a condition is true.
is_dir                  Checks whether the variable is a path to an
                        existing directory
is_file                 Checks whether the variable is a path to an
                        existing file
is_in                   Checks whether all elements of one variable are
                        in another
is_na                   Checks whether the variable is NA
is_readable             Checks whether the variable is a path to an
                        existing, readable file or directory
is_url                  Checks whether the variable is a valid URL
is_writeable            Checks whether the variable is a path to an
                        existing, writeable file or directory
msgr                    Extends messages, warnings and errors by adding
                        levels and log files
try_catch               Try to evaluate an expressions and capture any
                        messages, warnings or errors
try_map                 Apply a function over a vector or list,
                        capturing any errors to display at the end
try_pmap                Apply a function over a list of vectors,
                        capturing any errors to display at the end
warn                    Display a warning, and record it in a log file.
warn_if                 Display a warning, and record in a log file, if
                        a condition is true.
