Enum Expansion 

pub enum Expansion<'a> {
    Unset,
    Scalar(Cow<'a, str>),
    Array(Cow<'a, [String]>),
}

Expanded value of a variable

Variables with a Quirk may have their values computed dynamically when expanded, hence Cow in the enum values. Use Variable::expand to get an Expansion instance.

Variants

Unset

The value does not exist.

Scalar(Cow<'a, str>)

The value is a single string.

Array(Cow<'a, [String]>)

The value is an array of strings.

Implementations

impl Expansion<'_>

pub fn into_owned(self) -> Option<Value>

Converts into an owned value

pub fn as_ref(&self) -> Expansion<'_>

Converts to a borrowed value

pub fn len(&self) -> usize

Returns the “length” of the value.

For Unset, the length is 0. For Scalar, the length is the number of characters. For Array, the length is the number of strings.

pub fn is_empty(&self) -> bool

Tests whether the length is zero.

pub fn split(&self) -> impl Iterator<Item = &str>

Splits the expansion by colons.

If this expansion is Scalar, the value is separated at each occurrence of colon (:). For Array, each array item is returned without further splitting the value. For Unset, an empty iterator is returned.

let expansion = Expansion::from("/usr/local/bin:/usr/bin:/bin");
let values: Vec<&str> = expansion.split().collect();
assert_eq!(values, ["/usr/local/bin", "/usr/bin", "/bin"]);

let expansion = Expansion::from(vec!["foo".to_string(), "bar".to_string()]);
let values: Vec<&str> = expansion.split().collect();
assert_eq!(values, ["foo", "bar"]);

let expansion = Expansion::Unset;
let values: Vec<&str> = expansion.split().collect();
assert!(values.is_empty());

Trait Implementations

impl<'a> Clone for Expansion<'a>

fn clone(&self) -> Expansion<'a>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<'a> Debug for Expansion<'a>

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

Formats the value using the given formatter.

impl Default for Expansion<'_>

Returns Unset.

fn default() -> Self

Returns the “default value” for a type.

impl<'a> From<&'a [String]> for Expansion<'a>

fn from(values: &'a [String]) -> Self

Converts to this type from the input type.

impl<'a> From<&'a Expansion<'a>> for Expansion<'a>

fn from(expansion: &'a Expansion<'a>) -> Expansion<'a>

Converts to this type from the input type.

impl<'a> From<&'a String> for Expansion<'a>

fn from(value: &'a String) -> Self

Converts to this type from the input type.

impl<'a> From<&'a Value> for Expansion<'a>

fn from(value: &'a Value) -> Self

Converts to this type from the input type.

impl<'a> From<&'a Vec<String>> for Expansion<'a>

fn from(values: &'a Vec<String>) -> Self

Converts to this type from the input type.

impl<'a> From<&'a str> for Expansion<'a>

fn from(value: &'a str) -> Self

Converts to this type from the input type.

impl From<Expansion<'_>> for Option<Value>

fn from(expansion: Expansion<'_>) -> Option<Value>

Converts to this type from the input type.

impl<'a, V> From<Option<&'a V>> for Expansion<'a>

where Expansion<'a>: From<&'a V>,

fn from(value: Option<&'a V>) -> Self

Converts to this type from the input type.

impl From<Option<String>> for Expansion<'static>

fn from(value: Option<String>) -> Self

Converts to this type from the input type.

impl From<Option<Value>> for Expansion<'static>

fn from(value: Option<Value>) -> Self

Converts to this type from the input type.

impl From<String> for Expansion<'static>

fn from(value: String) -> Self

Converts to this type from the input type.

impl From<Value> for Expansion<'static>

fn from(value: Value) -> Self

Converts to this type from the input type.

impl From<Vec<String>> for Expansion<'static>

fn from(values: Vec<String>) -> Self

Converts to this type from the input type.

impl<'a> PartialEq for Expansion<'a>

fn eq(&self, other: &Expansion<'a>) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<'a> Eq for Expansion<'a>

impl<'a> StructuralPartialEq for Expansion<'a>