Struct BoxSupplierOnce

Source

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

Expand description

Box-based one-time supplier.

Uses Box<dyn FnOnce() -> T> for one-time value generation. Can only call get() once, consuming the supplier.

§Examples

§Lazy Initialization

use prism3_function::{BoxSupplierOnce, SupplierOnce};

let once = BoxSupplierOnce::new(|| {
    println!("Expensive initialization");
    42
});

let value = once.get(); // Prints: Expensive initialization
assert_eq!(value, 42);

§Moving Captured Values

use prism3_function::{BoxSupplierOnce, SupplierOnce};

let resource = String::from("data");
let once = BoxSupplierOnce::new(move || resource);

let value = once.get();
assert_eq!(value, "data");

§Author

Haixing Hu

Implementations§

Source §

impl<T> BoxSupplierOnce<T>

Source

pub fn new<F>(f: F) -> Self
where F: FnOnce() -> T + 'static,

Creates a new BoxSupplierOnce.

§Parameters

f - The closure to wrap

§Returns

A new BoxSupplierOnce<T> instance

§Examples

use prism3_function::{BoxSupplierOnce, SupplierOnce};

let once = BoxSupplierOnce::new(|| 42);
assert_eq!(once.get(), 42);

Examples found in repository ?

examples/supplier_demo.rs (lines 118-121)

114fn demo_box_supplier_once() {
115    println!("--- BoxSupplierOnce ---");
116
117    // Basic usage
118    let once = BoxSupplierOnce::new(|| {
119        println!("  Expensive initialization");
120        42
121    });
122    println!("Value: {}", once.get());
123
124    // Moving captured values
125    let data = String::from("Hello, World!");
126    let once = BoxSupplierOnce::new(move || data);
127    println!("Moved data: {}", once.get());
128    println!();
129}