qubit-function 0.16.0

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

use {
    crate::BiMutatingFunction,
    crate::functions::macros::impl_box_function_methods,
    crate::functions::macros::impl_function_common_methods,
    crate::functions::macros::impl_function_constant_method,
    crate::functions::macros::impl_function_debug_display,
};
use {
    crate::BiPredicate,
    crate::BoxConditionalBiMutatingFunction,
    crate::MutatingFunction,
};

/// The erased callback representation used by this implementation.
type BoxBiMutatingFunctionFn<T, U, R> = Box<dyn Fn(&mut T, &mut U) -> R>;

// ============================================================================
// BoxBiMutatingFunction - Box<dyn Fn(&mut T, &mut U) -> R>
// ============================================================================

/// BoxBiMutatingFunction - bi-mutating-function wrapper based on `Box<dyn Fn>`
///
/// A bi-mutating-function wrapper that provides single ownership with reusable
/// computation. Borrows both inputs mutably and can be called multiple times.
///
/// # Features
///
/// - **Based on**: `Box<dyn Fn(&mut T, &mut U) -> R>`
/// - **Ownership**: Single ownership, cannot be cloned
/// - **Reusability**: Can be called multiple times (borrows inputs mutably each
///   time)
/// - **Thread Safety**: Not thread-safe (no `Send + Sync` requirement)
#[must_use = "callback wrappers do nothing unless stored or invoked"]
pub struct BoxBiMutatingFunction<T, U, R> {
    /// The wrapped callback implementation.
    pub(super) function: BoxBiMutatingFunctionFn<T, U, R>,
    /// Diagnostic metadata associated with this callback.
    pub(super) metadata: crate::internal::CallbackMetadata,
}

// Implement BoxBiMutatingFunction
impl<T, U, R> BoxBiMutatingFunction<T, U, R> {
    // Generates: new(), new_with_name(), new_with_optional_name(), name(),
    // set_name()
    impl_function_common_methods!(
        BoxBiMutatingFunction<T, U, R>,
        (Fn(&mut T, &mut U) -> R + 'static),
        |f| Box::new(f)
    );

    // Generates: when(), and_then()
    impl_box_function_methods!(
        BoxBiMutatingFunction<T, U, R>,
        BoxConditionalBiMutatingFunction,
        MutatingFunction
    );
}

// Implement BiMutatingFunction trait for BoxBiMutatingFunction
impl<T, U, R> BiMutatingFunction<T, U, R> for BoxBiMutatingFunction<T, U, R> {
    #[inline(always)]
    fn apply(&self, first: &mut T, second: &mut U) -> R {
        (self.function)(first, second)
    }
}

// Implement constant method for BoxBiMutatingFunction
impl_function_constant_method!(BoxBiMutatingFunction<T, U, R>, mut 'static);

// Implement Debug and Display for BoxBiMutatingFunction
impl_function_debug_display!(BoxBiMutatingFunction<T, U, R>);