Struct holochain_json_api::json::JsonStringOption

pub struct JsonStringOption<T>(_);

Methods

impl<T> JsonStringOption<T>

pub fn map<__SHRINKWRAP_T, __SHRINKWRAP_F: FnMut(Option<T>) -> __SHRINKWRAP_T>(
    self,
    f: __SHRINKWRAP_F
) -> __SHRINKWRAP_T

Map a function over the wrapped value, consuming it in the process.

pub fn map_ref<__SHRINKWRAP_T, __SHRINKWRAP_F: FnMut(&Option<T>) -> __SHRINKWRAP_T>(
    &self,
    f: __SHRINKWRAP_F
) -> __SHRINKWRAP_T

Map a function over the wrapped value without consuming it.

impl<T> JsonStringOption<T>

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

Methods from Deref<Target = Option<T>>

#[must_use = "if you intended to assert that this has a value, consider `.unwrap()` instead"] pub fn is_some(&self) -> bool

Returns true if the option is a Some value.

Examples

let x: Option<u32> = Some(2);
assert_eq!(x.is_some(), true);

let x: Option<u32> = None;
assert_eq!(x.is_some(), false);

#[must_use = "if you intended to assert that this doesn\'t have a value, consider `.and_then(|| panic!(\"`Option` had a value when expected `None`\"))` instead"] pub fn is_none(&self) -> bool

Returns true if the option is a None value.

Examples

let x: Option<u32> = Some(2);
assert_eq!(x.is_none(), false);

let x: Option<u32> = None;
assert_eq!(x.is_none(), true);

#[must_use] pub fn contains<U>(&self, x: &U) -> bool where
    U: PartialEq<T>, 

🔬 This is a nightly-only experimental API. (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);

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

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);

pub fn as_pin_ref(self: Pin<&Option<T>>) -> Option<Pin<&T>>

Converts from Pin<&Option<T>> to Option<Pin<&T>>.

pub fn as_pin_mut(self: Pin<&mut Option<T>>) -> Option<Pin<&mut T>>

Converts from Pin<&mut Option<T>> to Option<Pin<&mut T>>.

pub fn iter(&self) -> Iter<T>

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);

pub fn as_deref(&self) -> Option<&<T as Deref>::Target>

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

impl<T> AsRef<Option<T>> for JsonStringOption<T>

fn as_ref(&self) -> &Option<T>

Performs the conversion.

impl<T> Borrow<Option<T>> for JsonStringOption<T>

fn borrow(&self) -> &Option<T>

Immutably borrows from an owned value.

impl<T> Deref for JsonStringOption<T>

type Target = Option<T>

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl<'de, T> Deserialize<'de> for JsonStringOption<T> where
    T: Deserialize<'de>, 

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error> where
    __D: Deserializer<'de>, 

Deserialize this value from the given Serde deserializer.

impl<T> Into<Option<T>> for JsonStringOption<T>

fn into(self) -> Option<T>

Performs the conversion.

impl TryInto<JsonStringOption<String>> for JsonString

type Error = JsonError

The type returned in the event of a conversion error.

fn try_into(self) -> Result<JsonStringOption<String>, Self::Error>

Performs the conversion.

impl<T> TryInto<JsonStringOption<T>> for JsonString where
    T: Into<JsonString> + DeserializeOwned, 

type Error = JsonError

The type returned in the event of a conversion error.

fn try_into(self) -> Result<JsonStringOption<T>, Self::Error>

Performs the conversion.