qubit-function 0.16.0

Functional programming traits and Box/Rc/Arc adapters for Rust, inspired by Java functional interfaces
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// =============================================================================
//    Copyright (c) 2025 - 2026 Haixing Hu.
//
//    SPDX-License-Identifier: Apache-2.0
//
//    Licensed under the Apache License, Version 2.0.
// =============================================================================
//! Defines the `RcConditionalStatefulBiConsumer` public type.

use {
    crate::BiPredicate,
    crate::RcBiPredicate,
    crate::RcStatefulBiConsumer,
    crate::StatefulBiConsumer,
    crate::consumers::macros::impl_conditional_consumer_clone,
    crate::consumers::macros::impl_conditional_consumer_debug_display,
    crate::consumers::macros::impl_shared_conditional_consumer,
};

// =======================================================================
// 9. RcConditionalStatefulBiConsumer - Rc-based Conditional BiConsumer
// =======================================================================

/// RcConditionalStatefulBiConsumer struct
///
/// A single-threaded conditional bi-consumer that only executes when a
/// predicate is satisfied. Uses `RcStatefulBiConsumer` and `RcBiPredicate` for
/// shared ownership within a single thread.
///
/// This type is typically created by calling `RcStatefulBiConsumer::when()` and
/// is designed to work with the `or_else()` method to create if-then-else
/// logic.
///
/// # Features
///
/// - **Shared Ownership**: Cloneable via `Rc`, multiple owners allowed
/// - **Single-Threaded**: Not thread-safe, cannot be sent across threads
/// - **Conditional Execution**: Only consumes when predicate returns `true`
/// - **No Lock Overhead**: More efficient than
///   `ArcConditionalStatefulBiConsumer`
///
/// # Examples
///
/// ```rust
/// use qubit_function::{BiConsumer, RcStatefulBiConsumer, StatefulBiConsumer};
/// use std::rc::Rc;
/// use std::cell::RefCell;
///
/// let log = Rc::new(RefCell::new(Vec::new()));
/// let l = log.clone();
/// let conditional = RcStatefulBiConsumer::new(move |x: &i32, y: &i32| {
///     l.borrow_mut().push(*x + *y);
/// }).when(|x: &i32, y: &i32| *x > 0 && *y > 0);
///
/// let conditional_clone = conditional.clone();
///
/// let mut value = 5;
/// let mut m = conditional;
/// m.accept(&value, &3);
/// assert_eq!(*log.borrow(), vec![8]);
/// ```
#[must_use = "callback wrappers do nothing unless stored or invoked"]
pub struct RcConditionalStatefulBiConsumer<T, U> {
    /// The wrapped consumer callback.
    pub(super) consumer: RcStatefulBiConsumer<T, U>,
    /// The predicate controlling conditional execution.
    pub(super) predicate: RcBiPredicate<T, U>,
}

// Use macro to generate and_then and or_else methods
impl_shared_conditional_consumer!(
    RcConditionalStatefulBiConsumer<T, U>,
    RcStatefulBiConsumer,
    StatefulBiConsumer,
    callback_bounds = ('static)
);

impl<T, U> StatefulBiConsumer<T, U> for RcConditionalStatefulBiConsumer<T, U> {
    fn accept(&mut self, first: &T, second: &U) {
        if self.predicate.test(first, second) {
            self.consumer.accept(first, second);
        }
    }
}

// Use macro to generate Clone implementation
impl_conditional_consumer_clone!(RcConditionalStatefulBiConsumer<T, U>);

// Use macro to generate Debug and Display implementations
impl_conditional_consumer_debug_display!(RcConditionalStatefulBiConsumer<T, U>);