Assert Argument is an Expression
assert_expr(
arg,
optional = FALSE,
arg_name = gsub("^enexpr\\((.*)\\)$", "\\1", rlang::caller_arg(arg)),
message = NULL,
class = "assert_expr",
call = parent.frame()
)The function throws an error if arg is not an expression, i.e. either
a symbol or a call, or returns the input invisibly otherwise
A function argument to be checked
Is the checked argument optional? If set to FALSE and arg
is NULL then an error is thrown
By default the expression specified for arg is used. If it is
of the form enexpr(<argument name>), the enexpr() part is removed. For example
if arg = enexpr(filter_add) is specified, arg_name defaults to "filter_add"
string passed to cli::cli_abort(message).
When NULL, default messaging is used (see examples for default messages).
"{arg_name}" can be used in messaging.
Subclass of the condition.
The execution environment of a currently running
function, e.g. call = caller_env(). The corresponding function
call is retrieved and mentioned in error messages as the source
of the error.
You only need to supply call when throwing a condition from a
helper function which wouldn't be relevant to mention in the
message.
Can also be NULL or a defused function call to
respectively not display any call or hard-code a code to display.
For more information about error calls, see Including function calls in error messages.
Checks for valid input and returns warning or errors messages:
assert_atomic_vector(),
assert_character_scalar(),
assert_character_vector(),
assert_data_frame(),
assert_date_vector(),
assert_expr_list(),
assert_filter_cond(),
assert_function(),
assert_integer_scalar(),
assert_list_element(),
assert_list_of(),
assert_logical_scalar(),
assert_named(),
assert_numeric_vector(),
assert_one_to_one(),
assert_param_does_not_exist(),
assert_s3_class(),
assert_same_type(),
assert_symbol(),
assert_unit(),
assert_vars(),
assert_varval_list()