Skip to contents

Attribute checks - Check if object allows attributes

is_attrs_allowed.Rd

In R, some objects do not allow attributes to be set on them. This function checks whether attr(x, which) <- value runs without errors. See attr() for details.

Up to R version 4.6.0, only three object types (typeof()) disallow attributes:

  • "primitive" starting in R 4.6.0.

  • "symbol" starting in R 3.5.0.

  • "NULL" starting in R 3.4.0.

Besides these, objects of type "char" and "any", which exist only in the internals of R, always return FALSE.

Usage

is_attrs_allowed(x, cnd_match = NULL, warn = "tw")

Arguments

x

[any] An object to test.

cnd_match

[character(1)] String to match in the condition message. If no match, the condition is re-thrown. Defaults to allow any message.

warn

["true" | "false" | "warn" | "error"] How to handle warnings: "false" to return FALSE; "true"`` for TRUE; "warn"to returnTRUEbut re-throw the warning; and"error"` to throw the warning as an error.

Value

[TRUE | FALSE] The scalar result of the test. Or, re-throws the caught condition.

Examples

is_attrs_allowed(mtcars) #> TRUE
#> [1] TRUE
is_attrs_allowed(NULL) #> FALSE
#> [1] FALSE