Truth                   Is the input TRUE/FALSE/NA?
are_identical           Are the inputs identical?
assert_engine           Throws an error if a condition isn't met
assertionError          Condition classes
bapply                  Wrapper to vapply that returns booleans
call_and_name           Call a function, and give the result names.
cause                   Get or set the '"cause"' attribute
coerce_to               Coerce variable to a different class
dont_stop               Run code without stopping
false                   FALSE, with a cause of failure.
get_name_in_parent      Get the name of a variable in the parent frame
is2                     Alternative version of is
merge.list              Merge two lists
merge_dots_with_list    Merge ellipsis args with a list.
na                      NA, with a cause of failure.
parenthesize            Wrap a string in brackets
print.scalar_with_cause
                        Print methods for objects with a cause
                        attribute
print_and_capture       Print a variable and capture the output
safe_deparse            Safe version of deparse
set_cause               Set a cause and return the input
strip_attributes        Strip all attributes from a variable
use_first               Only use the first element of a vector
