Struct lenient_version::Build [−][src]
pub struct Build<'input> { /* fields omitted */ }
Expand description
The build segment of a semantic Version.
Implementations
Methods from Deref<Target = Option<&'input str>>
🔬 This is a nightly-only experimental API. (option_result_contains
)
option_result_contains
)Returns true
if the option is a Some
value containing the given value.
Examples
#![feature(option_result_contains)] let x: Option<u32> = Some(2); assert_eq!(x.contains(&2), true); let x: Option<u32> = Some(3); assert_eq!(x.contains(&2), false); let x: Option<u32> = None; assert_eq!(x.contains(&2), false);
Converts from &Option<T>
to Option<&T>
.
Examples
Converts an Option<
String
>
into an Option<
usize
>
, preserving the original.
The map
method takes the self
argument by value, consuming the original,
so this technique uses as_ref
to first take an Option
to a reference
to the value inside the original.
let text: Option<String> = Some("Hello, world!".to_string()); // First, cast `Option<String>` to `Option<&String>` with `as_ref`, // then consume *that* with `map`, leaving `text` on the stack. let text_length: Option<usize> = text.as_ref().map(|s| s.len()); println!("still can print text: {:?}", text);
Converts from &mut Option<T>
to Option<&mut T>
.
Examples
let mut x = Some(2); match x.as_mut() { Some(v) => *v = 42, None => {}, } assert_eq!(x, Some(42));
Returns an iterator over the possibly contained value.
Examples
let x = Some(4); assert_eq!(x.iter().next(), Some(&4)); let x: Option<u32> = None; assert_eq!(x.iter().next(), None);
Returns a mutable iterator over the possibly contained value.
Examples
let mut x = Some(4); match x.iter_mut().next() { Some(v) => *v = 42, None => {}, } assert_eq!(x, Some(42)); let mut x: Option<u32> = None; assert_eq!(x.iter_mut().next(), None);
Inserts value
into the option then returns a mutable reference to it.
If the option already contains a value, the old value is dropped.
See also Option::get_or_insert
, which doesn’t update the value if
the option already contains Some
.
Example
let mut opt = None; let val = opt.insert(1); assert_eq!(*val, 1); assert_eq!(opt.unwrap(), 1); let val = opt.insert(2); assert_eq!(*val, 2); *val = 3; assert_eq!(opt.unwrap(), 3);
Inserts value
into the option if it is None
, then
returns a mutable reference to the contained value.
See also Option::insert
, which updates the value even if
the option already contains Some
.
Examples
let mut x = None; { let y: &mut u32 = x.get_or_insert(5); assert_eq!(y, &5); *y = 7; } assert_eq!(x, Some(7));
🔬 This is a nightly-only experimental API. (option_get_or_insert_default
)
option_get_or_insert_default
)Replaces the actual value in the option by the value given in parameter,
returning the old value if present,
leaving a Some
in its place without deinitializing either one.
Examples
let mut x = Some(2); let old = x.replace(5); assert_eq!(x, Some(5)); assert_eq!(old, Some(2)); let mut x = None; let old = x.replace(3); assert_eq!(x, Some(3)); assert_eq!(old, None);
Converts from Option<T>
(or &Option<T>
) to Option<&T::Target>
.
Leaves the original Option in-place, creating a new one with a reference
to the original one, additionally coercing the contents via Deref
.
Examples
let x: Option<String> = Some("hey".to_owned()); assert_eq!(x.as_deref(), Some("hey")); let x: Option<String> = None; assert_eq!(x.as_deref(), None);
Converts from Option<T>
(or &mut Option<T>
) to Option<&mut T::Target>
.
Leaves the original Option
in-place, creating a new one containing a mutable reference to
the inner type’s Deref::Target
type.
Examples
let mut x: Option<String> = Some("hey".to_owned()); assert_eq!(x.as_deref_mut().map(|x| { x.make_ascii_uppercase(); x }), Some("HEY".to_owned().as_mut_str()));
Trait Implementations
Performs the conversion.
Auto Trait Implementations
impl<'input> RefUnwindSafe for Build<'input>
impl<'input> UnwindSafe for Build<'input>
Blanket Implementations
Mutably borrows from an owned value. Read more