qubit_function/transformers/transformer_once/
box_transformer_once.rs

1/*******************************************************************************
2 *
3 *    Copyright (c) 2025 - 2026.
4 *    Haixing Hu, Qubit Co. Ltd.
5 *
6 *    All rights reserved.
7 *
8 ******************************************************************************/
9//! Defines the `BoxTransformerOnce` public type.
10
11#![allow(unused_imports)]
12
13use super::*;
14
15// ============================================================================
16// BoxTransformerOnce - Box<dyn FnOnce(T) -> R>
17// ============================================================================
18
19/// BoxTransformerOnce - consuming transformer wrapper based on
20/// `Box<dyn FnOnce>`
21///
22/// A transformer wrapper that provides single ownership with one-time use
23/// semantics. Consumes both self and the input value.
24///
25/// # Features
26///
27/// - **Based on**: `Box<dyn FnOnce(T) -> R>`
28/// - **Ownership**: Single ownership, cannot be cloned
29/// - **Reusability**: Can only be called once (consumes self and input)
30/// - **Thread Safety**: Not thread-safe (no `Send + Sync` requirement)
31///
32/// # Author
33///
34/// Haixing Hu
35pub struct BoxTransformerOnce<T, R> {
36    pub(super) function: Box<dyn FnOnce(T) -> R>,
37    pub(super) name: Option<String>,
38}
39
40// Implement BoxTransformerOnce
41impl<T, R> BoxTransformerOnce<T, R> {
42    impl_transformer_common_methods!(
43        BoxTransformerOnce<T, R>,
44        (FnOnce(T) -> R + 'static),
45        |f| Box::new(f)
46    );
47
48    impl_box_transformer_methods!(
49        BoxTransformerOnce<T, R>,
50        BoxConditionalTransformerOnce,
51        TransformerOnce
52    );
53}
54
55// Implement TransformerOnce trait for BoxTransformerOnce
56impl<T, R> TransformerOnce<T, R> for BoxTransformerOnce<T, R> {
57    fn apply(self, input: T) -> R {
58        (self.function)(input)
59    }
60
61    impl_box_once_conversions!(
62        BoxTransformerOnce<T, R>,
63        TransformerOnce,
64        FnOnce(T) -> R
65    );
66}
67
68// Implement constant method for BoxTransformerOnce
69impl_transformer_constant_method!(BoxTransformerOnce<T, R>);
70
71// Use macro to generate Debug and Display implementations
72impl_transformer_debug_display!(BoxTransformerOnce<T, R>);
73
74// ============================================================================
75// Blanket implementation for standard FnOnce trait
76// ============================================================================
77
78// Implement TransformerOnce for all FnOnce(T) -> R using macro
79impl_closure_once_trait!(
80    TransformerOnce<T, R>,
81    apply,
82    BoxTransformerOnce,
83    FnOnce(input: T) -> R
84);
qubit_function/transformers/transformer_once/box_transformer_once.rs

qubit_function/transformers/transformer_once/
box_transformer_once.rs
