qubit_function/transformers/transformer_once/
box_transformer_once.rs

1/*******************************************************************************
2 *
3 *    Copyright (c) 2025 - 2026 Haixing Hu.
4 *
5 *    SPDX-License-Identifier: Apache-2.0
6 *
7 *    Licensed under the Apache License, Version 2.0.
8 *
9 ******************************************************************************/
10// qubit-style: allow explicit-imports
11//! Defines the `BoxTransformerOnce` public type.
12
13#![allow(unused_imports)]
14
15use super::*;
16
17// ============================================================================
18// BoxTransformerOnce - Box<dyn FnOnce(T) -> R>
19// ============================================================================
20
21/// BoxTransformerOnce - consuming transformer wrapper based on
22/// `Box<dyn FnOnce>`
23///
24/// A transformer wrapper that provides single ownership with one-time use
25/// semantics. Consumes both self and the input value.
26///
27/// # Features
28///
29/// - **Based on**: `Box<dyn FnOnce(T) -> R>`
30/// - **Ownership**: Single ownership, cannot be cloned
31/// - **Reusability**: Can only be called once (consumes self and input)
32/// - **Thread Safety**: Not thread-safe (no `Send + Sync` requirement)
33///
34pub struct BoxTransformerOnce<T, R> {
35    pub(super) function: Box<dyn FnOnce(T) -> R>,
36    pub(super) name: Option<String>,
37}
38
39// Implement BoxTransformerOnce
40impl<T, R> BoxTransformerOnce<T, R> {
41    impl_transformer_common_methods!(
42        BoxTransformerOnce<T, R>,
43        (FnOnce(T) -> R + 'static),
44        |f| Box::new(f)
45    );
46
47    impl_box_transformer_methods!(
48        BoxTransformerOnce<T, R>,
49        BoxConditionalTransformerOnce,
50        TransformerOnce
51    );
52}
53
54// Implement TransformerOnce trait for BoxTransformerOnce
55impl<T, R> TransformerOnce<T, R> for BoxTransformerOnce<T, R> {
56    fn apply(self, input: T) -> R {
57        (self.function)(input)
58    }
59
60    impl_box_once_conversions!(
61        BoxTransformerOnce<T, R>,
62        TransformerOnce,
63        FnOnce(T) -> R
64    );
65}
66
67// Implement constant method for BoxTransformerOnce
68impl_transformer_constant_method!(BoxTransformerOnce<T, R>);
69
70// Use macro to generate Debug and Display implementations
71impl_transformer_debug_display!(BoxTransformerOnce<T, R>);
72
73// ============================================================================
74// Blanket implementation for standard FnOnce trait
75// ============================================================================
76
77// Implement TransformerOnce for all FnOnce(T) -> R using macro
78impl_closure_once_trait!(
79    TransformerOnce<T, R>,
80    apply,
81    BoxTransformerOnce,
82    FnOnce(input: T) -> R
83);
qubit_function/transformers/transformer_once/box_transformer_once.rs

qubit_function/transformers/transformer_once/
box_transformer_once.rs
