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
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
// =============================================================================
// Copyright (c) 2025 - 2026 Haixing Hu.
//
// SPDX-License-Identifier: Apache-2.0
//
// Licensed under the Apache License, Version 2.0.
// =============================================================================
//! # Closure Once Trait Implementation Macro
//!
//! This module provides the `impl_closure_once_trait!` macro for implementing
//! closure-based once traits.
//!
//! ## Overview
//!
//! The macro generates the semantic trait implementation for closures with
//! once semantics. It automatically infers the implementation from the
//! function signature and trait name.
//!
//! ## Generated Method
//!
//! - Core semantic method: Direct delegation to the underlying closure
//!
//! ## Usage
//!
//! The macro is typically used beside trait definitions to provide consistent
//! closure implementations across different once traits.
/// Implements a semantic once trait for closures.
///
/// This macro generates the core semantic method for once traits implemented
/// by closures. It automatically infers everything from the function signature
/// and trait name.
///
/// # Parameters
///
/// * `$trait_name<$(generics),*>` - Full trait name with generics (e.g.,
/// `ConsumerOnce<T>`, `BiFunctionOnce<T, U, R>`)
/// * `$method_name` - Core method name (e.g., `accept`, `apply`)
/// * `$box_type` - Box wrapper type (e.g., `BoxConsumerOnce`,
/// `BoxBiFunctionOnce`)
/// * `$fn_trait` - Function signature (e.g., `FnOnce(value: &T)`,
/// `FnOnce(first: &T, second: &U) -> R`)
///
/// # Generated implementation
///
/// ```text
/// impl<F> ConsumerOnce<i32> for F
/// where
/// F: FnOnce(&i32),
/// {
/// fn accept(self, value: &i32);
/// }
/// ```
///
/// # Examples
///
/// ```text
/// impl_closure_once_trait!(
/// ConsumerOnce<i32>,
/// accept,
/// BoxConsumerOnce,
/// FnOnce(value: &i32)
/// );
///
/// impl_closure_once_trait!(
/// FunctionOnce<i32, i32>,
/// apply,
/// BoxFunctionOnce,
/// FnOnce(input: &i32) -> i32
/// );
///
/// impl_closure_once_trait!(
/// BiFunctionOnce<i32, i32, i32>,
/// apply,
/// BoxBiFunctionOnce,
/// FnOnce(first: &i32, second: &i32) -> i32
/// );
/// ```
}
};
// ==================== Public Interface ====================
// No return value version
=>