stabilize_present: Require a value to be non-NULL

In stbl: Stabilize Function Arguments

Require a value to be non-NULL

Description

stabilize_present() validates that a value is not NULL. Any non-NULL value passes through unchanged. This is useful as an element specification in stabilize_lst() when you need to require a named element without imposing any type constraints on its value.

Usage

stabilize_present(
  x,
  x_arg = caller_arg(x),
  call = caller_env(),
  x_class = object_type(x)
)

Arguments

x	The argument to stabilize.
x_arg	⁠(length-1 character)⁠ The name of the argument being stabilized to use in error messages. The automatic value will work in most cases, or pass it through from higher-level functions to make error messages clearer in unexported functions.
call	(environment) The execution environment to mention as the source of error messages.
x_class	⁠(length-1 character)⁠ The class name of the argument being stabilized to use in error messages. Use this if you remove a special class from the object before checking its coercion, but want the error message to match the original class.

Value

The value, unchanged.

See Also

Other list functions: specify_lst(), stabilize_lst(), to_lst()

Other stabilization functions: stabilize_arg(), stabilize_chr(), stabilize_dbl(), stabilize_df(), stabilize_fct(), stabilize_int(), stabilize_lgl(), stabilize_lst()

Examples

stabilize_present("any value")
stabilize_present(list(1, 2, 3))
try(stabilize_present(NULL))

# Use as a named element spec in stabilize_lst()
stabilize_lst(list(data = mtcars), data = stabilize_present)

stbl documentation built on April 4, 2026, 5:06 p.m.