Struct alure::MaybeNumber [−][src]
pub struct MaybeNumber(_);
Expand description
Representation of the value from a register, which may be None
if the register is unset.
Implementations
Creates MaybeNumber
without assigning a value to it
Creates MaybeNumber
assigning a value to it
Methods from Deref<Target = Option<Number>>
🔬 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 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);
Trait Implementations
Returns the “default value” for a type. Read more
Performs the conversion.
Performs the conversion.
Performs the conversion.
Performs the conversion.
Performs the conversion.
Performs the conversion.
This method tests for self
and other
values to be equal, and is used
by ==
. Read more
This method tests for !=
.
Auto Trait Implementations
impl RefUnwindSafe for MaybeNumber
impl Send for MaybeNumber
impl Sync for MaybeNumber
impl Unpin for MaybeNumber
impl UnwindSafe for MaybeNumber
Blanket Implementations
Mutably borrows from an owned value. Read more