Struct Environment 

pub struct Environment { /* private fields */ }

An Environment stores a map of types to values.

Each type can have at most one value in the environment. The environment is used to pass contextual information from parent views to child views.

Examples

use waterui_core::Environment;

let mut env = Environment::new();
env.insert(String::from("hello"));

// Get the value back
assert_eq!(env.get::<String>(), Some(&String::from("hello")));

// Remove the value
env.remove::<String>();
assert_eq!(env.get::<String>(), None);

Implementations

impl Environment

pub const fn new() -> Environment

Creates a new empty environment.

pub fn store<K, V>(self, value: V) -> Environment

where K: 'static, V: 'static,

Stores a value in the environment indexed by type K.

Arguments

• value - The value to store

pub fn query<K, V>(&self) -> Option<&V>

where K: 'static, V: 'static,

Queries for a value in the environment indexed by type K.

Returns

An optional reference to the stored value

pub fn install(&mut self, plugin: impl Plugin) -> &mut Environment

Installs a plugin into the environment.

Plugins can register values or modifiers that will be available to all views.

pub fn insert<T>(&mut self, value: T)

where T: 'static,

Inserts a value into the environment.

If a value of the same type already exists, it will be replaced.

pub fn insert_hook<T, V>( &mut self, hook: impl Fn(&Environment, T) -> V + 'static, )

where T: ViewConfiguration, V: View,

Inserts a view configuration hook into the environment.

Hooks allow you to intercept and modify view configurations globally.

pub fn remove<T>(&mut self)

where T: 'static,

Removes a value from the environment by its type.

pub fn with<T>(&mut self, value: T) -> &mut Environment

where T: 'static,

Adds a value to the environment and returns the modified environment.

This is a fluent interface for chaining multiple additions.

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

where T: 'static,

Retrieves a reference to a value from the environment by its type.

Returns None if no value of the requested type exists.

Panics

This function will panic if a value of the requested type exists in the environment, but the stored value cannot be downcast to the requested type. This should never happen if only insert and with are used to add values.

Trait Implementations

impl Clone for Environment

fn clone(&self) -> Environment

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Environment

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

Formats the value using the given formatter.

impl Default for Environment

fn default() -> Environment

Returns the “default value” for a type.

impl Extractor for Environment

fn extract(env: &Environment) -> Result<Environment, Error>

Extracts the Environment itself by creating a clone.

impl MetadataKey for Environment