Struct fallback::Fallback

pub struct Fallback<T> { /* private fields */ }

Stores two Option, and provides functionality to fallback.

Basically, you provides a function returns Option, and Fallback handles the fallback.

let data = Some("hello");
let base_data = Some("123");
let fallback = Fallback::new(data, base_data);
let num = fallback.and_then(|s| s.parse::<i32>().ok());
assert_eq!(num, Some(123));

And you can map the Fallback:

let data = Some(123);
let base_data = Some(123456);
let fallback = Fallback::new(data, base_data);
let fallback = fallback.map(|i| i.to_string());
let s = fallback.and_then(|s| if s.len() > 3 { Some(s) } else { None });
assert_eq!(s, Some("123456".to_string()));

Implementations

impl<T> Fallback<T>

pub const fn new(data: Option<T>, base_data: Option<T>) -> Self

Creates a new Fallback.

pub const fn is_some(&self) -> bool

Returns false if both data and base_data are None.

pub const fn as_ref(&self) -> Fallback<&T>

Converts from &Fallback<T> to Fallback<&T>.

pub fn and_then<V>(self, f: impl FnMut(T) -> Option<V>) -> Option<V>

Fallbacks the data or part of data.

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

Fallbacks the total data.

pub fn map<V>(self, f: impl FnMut(T) -> V) -> Fallback<V>

Maps to a new Fallback.

pub fn unzip(self) -> (Option<T>, Option<T>)

Exacts the data and base_data.

impl<T> Fallback<Option<T>>

pub fn flatten(self) -> Fallback<T>

Converts from Fallback<Option<T>> to Fallback<T>.

impl<T> Fallback<T>

where for<'a> &'a T: IntoIterator, for<'a> <&'a T as IntoIterator>::IntoIter: ExactSizeIterator,

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

Treats the empty container as None and fallbacks.

impl<T: AsRef<str>> Fallback<T>

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

Treats the empty string as None and fallbacks.

impl<T: FallbackSpec> Fallback<T>

pub fn spec(self) -> T::SpecType

Get the specialized fallback object.

Trait Implementations

impl<T> From<Fallback<T>> for Option<T>

fn from(f: Fallback<T>) -> Self

Converts to this type from the input type.

impl<T: IntoIterator> IntoIterator for Fallback<T>

type Item = Fallback<<T as IntoIterator>::Item>

The type of the elements being iterated over.

type IntoIter = FallbackIter<Fuse<<T as IntoIterator>::IntoIter>>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.