qubit_function/transformers/stateful_transformer/
box_stateful_transformer.rs

1/*******************************************************************************
2 *
3 *    Copyright (c) 2025 - 2026.
4 *    Haixing Hu, Qubit Co. Ltd.
5 *
6 *    All rights reserved.
7 *
8 ******************************************************************************/
9//! Defines the `BoxStatefulTransformer` public type.
10
11#![allow(unused_imports)]
12
13use super::*;
14
15// ============================================================================
16// BoxStatefulTransformer - Box<dyn FnMut(T) -> R>
17// ============================================================================
18
19/// BoxStatefulTransformer - transformer wrapper based on `Box<dyn FnMut>`
20///
21/// A transformer wrapper that provides single ownership with reusable stateful
22/// transformation. The transformer consumes the input and can be called
23/// multiple times while maintaining internal state.
24///
25/// # Features
26///
27/// - **Based on**: `Box<dyn FnMut(T) -> R>`
28/// - **Ownership**: Single ownership, cannot be cloned
29/// - **Reusability**: Can be called multiple times (each call consumes
30///   its input)
31/// - **Thread Safety**: Not thread-safe (no `Send + Sync` requirement)
32/// - **Statefulness**: Can modify internal state between calls
33///
34/// # Author
35///
36/// Haixing Hu
37pub struct BoxStatefulTransformer<T, R> {
38    pub(super) function: Box<dyn FnMut(T) -> R>,
39    pub(super) name: Option<String>,
40}
41
42impl<T, R> BoxStatefulTransformer<T, R> {
43    impl_transformer_common_methods!(
44        BoxStatefulTransformer<T, R>,
45        (FnMut(T) -> R + 'static),
46        |f| Box::new(f)
47    );
48
49    impl_box_transformer_methods!(
50        BoxStatefulTransformer<T, R>,
51        BoxConditionalStatefulTransformer,
52        StatefulTransformer
53    );
54}
55
56// Implement constant method for BoxStatefulTransformer
57impl_transformer_constant_method!(stateful BoxStatefulTransformer<T, R>);
58
59// Implement Debug and Display for BoxStatefulTransformer
60impl_transformer_debug_display!(BoxStatefulTransformer<T, R>);
61
62// Implement StatefulTransformer trait for BoxStatefulTransformer
63impl<T, R> StatefulTransformer<T, R> for BoxStatefulTransformer<T, R> {
64    fn apply(&mut self, input: T) -> R {
65        (self.function)(input)
66    }
67
68    // Generates: into_box(), into_rc(), into_fn(), into_once()
69    impl_box_conversions!(
70        BoxStatefulTransformer<T, R>,
71        RcStatefulTransformer,
72        FnMut(T) -> R,
73        BoxTransformerOnce
74    );
75
76    // do NOT override StatefulTransformer::to_xxx() because BoxStatefulTransformer is not Clone
77    // and calling BoxStatefulTransformer::to_xxx() will cause a compile error
78}
qubit_function/transformers/stateful_transformer/box_stateful_transformer.rs

qubit_function/transformers/stateful_transformer/
box_stateful_transformer.rs
