Enum RArg 

pub enum RArg<T> {
    Missing,
    Null,
    Value(T),
}

The three states of an R function argument.

In R, missing(x) returns TRUE when the caller didn’t provide x at all, while is.null(x) returns TRUE when the caller explicitly passed NULL. These are semantically different and many builtins branch on the distinction.

Use RArg<T> as a field type in #[derive(FromArgs)] structs when you need the full three-way distinction. For simpler cases, use plain T (required) or Option<T> (missing → None, NULL coerces or errors).

Variants

Missing

Caller did not provide this argument. missing(x) would return TRUE.

Null

Caller explicitly passed NULL.

Value(T)

Caller provided a value (possibly NA — that’s inside T).

Implementations

impl<T> RArg<T>

pub fn is_missing(&self) -> bool

pub fn is_null(&self) -> bool

pub fn value(&self) -> Option<&T>

pub fn into_value(self) -> Option<T>

pub fn optional(self) -> Option<T>

Collapse both Missing and Null to None, Value to Some.

pub fn or_default(self, default: T) -> Self

Use a default when missing, but propagate NULL distinctly.

pub fn unwrap_or(self, default: T) -> T

Unwrap to value, using default for both Missing and Null.

pub fn unwrap_or_else(self, f: impl FnOnce() -> T) -> T

Unwrap to value, using f() for both Missing and Null.

pub fn map<U>(self, f: impl FnOnce(T) -> U) -> RArg<U>

Trait Implementations

impl<T: Clone> Clone for RArg<T>

fn clone(&self) -> RArg<T>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T: Debug> Debug for RArg<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.