qubit-function 0.16.0

Functional programming traits and Box/Rc/Arc adapters for Rust, inspired by Java functional interfaces
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86

// =============================================================================
//    Copyright (c) 2025 - 2026 Haixing Hu.
//
//    SPDX-License-Identifier: Apache-2.0
//
//    Licensed under the Apache License, Version 2.0.
// =============================================================================
//! Defines the `BoxTransformerOnce` public type.

use {
    crate::BoxConditionalTransformerOnce,
    crate::Predicate,
};
use {
    crate::TransformerOnce,
    crate::macros::impl_closure_once_trait,
    crate::transformers::macros::impl_box_transformer_methods,
    crate::transformers::macros::impl_transformer_common_methods,
    crate::transformers::macros::impl_transformer_constant_method,
    crate::transformers::macros::impl_transformer_debug_display,
};

// ============================================================================
// BoxTransformerOnce - Box<dyn FnOnce(T) -> R>
// ============================================================================

/// BoxTransformerOnce - consuming transformer wrapper based on
/// `Box<dyn FnOnce>`
///
/// A transformer wrapper that provides single ownership with one-time use
/// semantics. Consumes both self and the input value.
///
/// # Features
///
/// - **Based on**: `Box<dyn FnOnce(T) -> R>`
/// - **Ownership**: Single ownership, cannot be cloned
/// - **Reusability**: Can only be called once (consumes self and input)
/// - **Thread Safety**: Not thread-safe (no `Send + Sync` requirement)
#[must_use = "callback wrappers do nothing unless stored or invoked"]
pub struct BoxTransformerOnce<T, R> {
    /// The wrapped callback implementation.
    pub(super) function: Box<dyn FnOnce(T) -> R>,
    /// Diagnostic metadata associated with this callback.
    pub(super) metadata: crate::internal::CallbackMetadata,
}

// Implement BoxTransformerOnce
impl<T, R> BoxTransformerOnce<T, R> {
    impl_transformer_common_methods!(
        BoxTransformerOnce<T, R>,
        (FnOnce(T) -> R + 'static),
        |f| Box::new(f)
    );

    impl_box_transformer_methods!(
        BoxTransformerOnce<T, R>,
        BoxConditionalTransformerOnce,
        TransformerOnce
    );
}

// Implement TransformerOnce trait for BoxTransformerOnce
impl<T, R> TransformerOnce<T, R> for BoxTransformerOnce<T, R> {
    #[inline(always)]
    fn apply(self, input: T) -> R {
        (self.function)(input)
    }
}

// Implement constant method for BoxTransformerOnce
impl_transformer_constant_method!(BoxTransformerOnce<T, R>);

// Use macro to generate Debug and Display implementations
impl_transformer_debug_display!(BoxTransformerOnce<T, R>);

// ============================================================================
// Blanket implementation for standard FnOnce trait
// ============================================================================

// Implement TransformerOnce for all FnOnce(T) -> R using macro
impl_closure_once_trait!(
    TransformerOnce<T, R>,
    apply,
    BoxTransformerOnce,
    FnOnce(input: T) -> R
);