Trait Consumer 

pub trait Consumer<T> {
    // Required method
    fn accept(&self, value: &T);

    // Provided methods
    fn into_box(self) -> BoxConsumer<T>
       where Self: Sized + 'static { ... }
    fn into_rc(self) -> RcConsumer<T>
       where Self: Sized + 'static { ... }
    fn into_arc(self) -> ArcConsumer<T>
       where Self: Sized + Send + Sync + 'static { ... }
    fn into_fn(self) -> impl Fn(&T)
       where Self: Sized + 'static { ... }
    fn into_once(self) -> BoxConsumerOnce<T>
       where Self: Sized + 'static { ... }
    fn to_box(&self) -> BoxConsumer<T>
       where Self: Clone + 'static { ... }
    fn to_rc(&self) -> RcConsumer<T>
       where Self: Clone + 'static { ... }
    fn to_arc(&self) -> ArcConsumer<T>
       where Self: Clone + Send + Sync + 'static { ... }
    fn to_fn(&self) -> impl Fn(&T)
       where Self: Clone + 'static { ... }
    fn to_once(&self) -> BoxConsumerOnce<T>
       where Self: Clone + 'static { ... }
}

Consumer trait - Unified non-mutating consumer interface

It is similar to the Fn(&T) trait in the standard library.

Defines the core behavior of all non-mutating consumer types. The API uses &self and shared input references, so callers can use a consumer without granting mutable access to the consumer wrapper or input value.

Auto-implementation

• All closures implementing Fn(&T)
• BoxConsumer<T>, ArcConsumer<T>, RcConsumer<T>

Features

• Unified Interface: All non-mutating consumer types share the same accept method signature
• Auto-implementation: Closures automatically implement this trait with zero overhead
• Type Conversion: Easy conversion between different ownership models
• Generic Programming: Write functions that work with any non-mutating consumer type
• No Wrapper Interior Mutability: No need for Mutex or RefCell in the wrapper, making shared ownership more efficient

Examples

use qubit_function::{Consumer, BoxConsumer};

fn apply_consumer<C: Consumer<i32>>(consumer: &C, value: &i32) {
    consumer.accept(value);
}

let box_con = BoxConsumer::new(|x: &i32| {
    println!("Value: {}", x);
});
apply_consumer(&box_con, &5);

Author

Haixing Hu

Required Methods

fn accept(&self, value: &T)

Execute non-mutating consumption operation

Performs an operation on the given reference. The operation typically reads input values or produces side effects, but neither modifies the input value nor the consumer’s own state.

Parameters

• value - Reference to the value to consume

Examples

use qubit_function::{Consumer, BoxConsumer};

let consumer = BoxConsumer::new(|x: &i32| println!("{}", x));
consumer.accept(&5);

Provided Methods

fn into_box(self) -> BoxConsumer<T>

where Self: Sized + 'static,

Convert to BoxConsumer

⚠️ Consumes self: The original consumer will be unavailable after calling this method.

Returns

Returns the wrapped BoxConsumer<T>

Examples found in repository

examples/consumers/consumer_demo.rs (line 358)

fn main() {
    println!("=== Consumer Examples ===\n");
    println!("Note: Consumer only reads values, does not modify the original value");
    println!("If you need to modify values, please refer to mutator_demo.rs\n");

    // ========================================================================
    // Example 1: BoxConsumer basic usage
    // ========================================================================
    println!("Example 1: BoxConsumer basic usage");
    println!("{}", "-".repeat(50));

    let consumer = BoxConsumer::new(|x: &i32| {
        println!("Read and calculate: {} * 2 = {}", x, x * 2);
    });
    let value = 5;
    println!("Value: {}", value);
    consumer.accept(&value);
    println!("Value remains: {} (not modified)\n", value);

    // ========================================================================
    // Example 2: BoxConsumer method chaining
    // ========================================================================
    println!("Example 2: BoxConsumer method chaining");
    println!("{}", "-".repeat(50));

    let results = Arc::new(Mutex::new(Vec::new()));
    let r1 = results.clone();
    let r2 = results.clone();
    let r3 = results.clone();

    let chained = BoxConsumer::new(move |x: &i32| {
        r1.lock().unwrap().push(*x * 2);
    })
    .and_then(move |x: &i32| {
        r2.lock().unwrap().push(*x + 10);
    })
    .and_then(move |x: &i32| {
        r3.lock().unwrap().push(*x);
        println!("Processing value: {}", x);
    });

    let value = 5;
    println!("Initial value: {}", value);
    chained.accept(&value);
    println!("Collected results: {:?}", *results.lock().unwrap());
    println!("Original value: {} (not modified)\n", value);

    // ========================================================================
    // Example 3: Closure extension methods
    // ========================================================================
    println!("Example 3: Direct use of extension methods on closures");
    println!("{}", "-".repeat(50));

    let result = Arc::new(Mutex::new(0));
    let r1 = result.clone();
    let r2 = result.clone();

    let closure_chain = (move |x: &i32| {
        *r1.lock().unwrap() = *x * 2;
    })
    .and_then(move |_x: &i32| {
        *r2.lock().unwrap() += 10;
    });

    let value = 5;
    println!("Initial value: {}", value);
    closure_chain.accept(&value);
    println!("Calculation result: {}", *result.lock().unwrap());
    println!("Original value: {} (not modified)\n", value);

    // ========================================================================
    // Example 4: BoxConsumer factory methods
    // ========================================================================
    println!("Example 4: BoxConsumer factory methods");
    println!("{}", "-".repeat(50));

    // noop
    println!("noop - does nothing:");
    let noop = BoxConsumer::<i32>::noop();
    let value = 42;
    noop.accept(&value);
    println!("Value: {}\n", value);

    // print
    print!("print - prints value: ");
    let print = BoxConsumer::new(|x: &i32| println!("{}", x));
    let value = 42;
    print.accept(&value);
    println!();

    // print with prefix
    let print_with = BoxConsumer::new(|x: &i32| println!("Value is: {}", x));
    let value = 42;
    print_with.accept(&value);
    println!();

    // ========================================================================
    // Example 5: Conditional Consumer
    // ========================================================================
    println!("Example 5: Conditional Consumer");
    println!("{}", "-".repeat(50));

    // when
    let mut check_positive =
        BoxStatefulConsumer::new(|x: &i32| println!("Positive: {}", x)).when(|x: &i32| *x > 0);

    let positive = 5;
    let negative = -5;
    print!("Check {}: ", positive);
    check_positive.accept(&positive);
    print!("Check {}: ", negative);
    check_positive.accept(&negative);
    println!("(negative numbers not printed)\n");

    // when().or_else()
    let mut categorize = BoxStatefulConsumer::new(|x: &i32| println!("Positive: {}", x))
        .when(|x: &i32| *x > 0)
        .or_else(|x: &i32| println!("Non-positive: {}", x));

    let positive = 10;
    let negative = -10;
    categorize.accept(&positive);
    categorize.accept(&negative);
    println!();

    // ========================================================================
    // Example 6: ArcConsumer - multi-threaded sharing
    // ========================================================================
    println!("Example 6: ArcConsumer - multi-threaded sharing");
    println!("{}", "-".repeat(50));

    let shared = ArcConsumer::new(|x: &i32| println!("Processing value: {}", x * 2));

    // Clone for another thread
    let shared_clone = shared.clone();
    let handle = thread::spawn(move || {
        let value = 5;
        let consumer = shared_clone;
        consumer.accept(&value);
        value
    });

    // Use in main thread
    let value = 3;
    let consumer = shared;
    consumer.accept(&value);

    let thread_result = handle.join().unwrap();
    println!("Thread result: {}\n", thread_result);

    // ========================================================================
    // Example 7: ArcConsumer composition (does not consume original consumer)
    // ========================================================================
    println!("Example 7: ArcConsumer composition (borrowing &self)");
    println!("{}", "-".repeat(50));

    let double = ArcConsumer::new(|x: &i32| println!("double: {}", x * 2));
    let add_ten = ArcConsumer::new(|x: &i32| println!("add_ten: {}", x + 10));

    // Composition does not consume original consumer
    let pipeline1 = double.and_then(add_ten.clone());
    let pipeline2 = add_ten.and_then(double.clone());

    let value1 = 5;
    let p1 = pipeline1;
    print!("pipeline1 processing 5: ");
    p1.accept(&value1);

    let value2 = 5;
    let p2 = pipeline2;
    print!("pipeline2 processing 5: ");
    p2.accept(&value2);

    // double and add_ten are still available
    let value3 = 10;
    let d = double;
    print!("Original double still available, processing 10: ");
    d.accept(&value3);
    println!();

    // ========================================================================
    // Example 8: RcConsumer - single-threaded sharing
    // ========================================================================
    println!("Example 8: RcConsumer - single-threaded sharing");
    println!("{}", "-".repeat(50));

    let rc_consumer = RcConsumer::new(|x: &i32| println!("Processing: {}", x * 2));

    // Clone multiple copies
    let clone1 = rc_consumer.clone();
    let clone2 = rc_consumer.clone();

    let value1 = 5;
    let c1 = clone1;
    print!("clone1 processing 5: ");
    c1.accept(&value1);

    let value2 = 3;
    let c2 = clone2;
    print!("clone2 processing 3: ");
    c2.accept(&value2);

    let value3 = 7;
    let c3 = rc_consumer;
    print!("Original processing 7: ");
    c3.accept(&value3);
    println!();

    // ========================================================================
    // Example 9: RcConsumer composition (borrowing &self)
    // ========================================================================
    println!("Example 9: RcConsumer composition (borrowing &self)");
    println!("{}", "-".repeat(50));

    let double = RcConsumer::new(|x: &i32| println!("double: {}", x * 2));
    let add_ten = RcConsumer::new(|x: &i32| println!("add_ten: {}", x + 10));

    let pipeline1 = double.and_then(add_ten.clone());
    let pipeline2 = add_ten.and_then(double.clone());

    let value1 = 5;
    let p1 = pipeline1;
    print!("pipeline1 processing 5: ");
    p1.accept(&value1);

    let value2 = 5;
    let p2 = pipeline2;
    print!("pipeline2 processing 5: ");
    p2.accept(&value2);
    println!();

    // ========================================================================
    // Example 10: Unified Consumer trait
    // ========================================================================
    println!("Example 10: Unified Consumer trait");
    println!("{}", "-".repeat(50));

    fn log_all<C: Consumer<i32>>(consumer: &mut C, values: &[i32]) {
        for value in values.iter() {
            consumer.accept(value);
        }
    }

    let values = vec![1, 2, 3, 4, 5];

    let mut box_con = BoxConsumer::new(|x: &i32| print!("{} ", x * 2));
    print!("BoxConsumer processing {:?}: ", values);
    log_all(&mut box_con, &values);
    println!();

    let mut arc_con = ArcConsumer::new(|x: &i32| print!("{} ", x * 2));
    print!("ArcConsumer processing {:?}: ", values);
    log_all(&mut arc_con, &values);
    println!();

    let mut rc_con = RcConsumer::new(|x: &i32| print!("{} ", x * 2));
    print!("RcConsumer processing {:?}: ", values);
    log_all(&mut rc_con, &values);
    println!();

    let mut closure = |x: &i32| print!("{} ", x * 2);
    print!("Closure processing {:?}: ", values);
    log_all(&mut closure, &values);
    println!("\n");

    // ========================================================================
    // Example 11: Data validation and logging
    // ========================================================================
    println!("Example 11: Data validation and logging");
    println!("{}", "-".repeat(50));

    let validator = BoxConsumer::new(|x: &i32| {
        let status = if *x >= 0 && *x <= 100 {
            "valid"
        } else {
            "out of range"
        };
        println!("Validate {}: {}", x, status);
    });

    let logger = BoxConsumer::new(|x: &i32| {
        println!("Log to file: value={}, square={}", x, x * x);
    });

    let pipeline = validator.and_then(logger);

    let test_values = vec![-50, 30, 200];
    for value in test_values {
        pipeline.accept(&value);
    }
    println!();

    // ========================================================================
    // Example 12: String analysis
    // ========================================================================
    println!("Example 12: String analysis");
    println!("{}", "-".repeat(50));

    let string_analyzer = BoxConsumer::new(|s: &String| {
        println!("Length: {}", s.len());
    })
    .and_then(|s: &String| {
        println!("Lowercase: {}", s.to_lowercase());
    })
    .and_then(|s: &String| {
        println!("Uppercase: {}", s.to_uppercase());
    })
    .and_then(|s: &String| {
        let word_count = s.split_whitespace().count();
        println!("Word count: {}", word_count);
    });

    let text = String::from("Hello World");
    println!("Analyzing text: \"{}\"", text);
    string_analyzer.accept(&text);
    println!("Original text: \"{}\" (not modified)\n", text);

    // ========================================================================
    // Example 13: Type conversion
    // ========================================================================
    println!("Example 13: Type conversion");
    println!("{}", "-".repeat(50));

    // Closure -> BoxConsumer
    let closure = |x: &i32| print!("Processing: {} ", x * 2);
    let box_con = Consumer::into_box(closure);
    let value = 5;
    print!("Closure -> BoxConsumer: ");
    box_con.accept(&value);
    println!();

    // Closure -> RcConsumer
    let closure = |x: &i32| print!("Processing: {} ", x * 2);
    let rc_con = Consumer::into_rc(closure);
    let value = 5;
    print!("Closure -> RcConsumer: ");
    rc_con.accept(&value);
    println!();

    // Closure -> ArcConsumer
    let closure = |x: &i32| print!("Processing: {} ", x * 2);
    let arc_con = Consumer::into_arc(closure);
    let value = 5;
    print!("Closure -> ArcConsumer: ");
    arc_con.accept(&value);
    println!();

    // BoxConsumer -> RcConsumer
    let box_con = BoxConsumer::new(|x: &i32| print!("Processing: {} ", x * 2));
    let rc_con = box_con.into_rc();
    let value = 5;
    print!("BoxConsumer -> RcConsumer: ");
    rc_con.accept(&value);
    println!();

    // RcConsumer -> BoxConsumer
    let rc_con = RcConsumer::new(|x: &i32| print!("Processing: {} ", x * 2));
    let box_con = rc_con.into_box();
    let value = 5;
    print!("RcConsumer -> BoxConsumer: ");
    box_con.accept(&value);
    println!("\n");

    // ========================================================================
    // Example 14: Custom types
    // ========================================================================
    println!("Example 14: Custom types");
    println!("{}", "-".repeat(50));

    #[derive(Debug, Clone)]
    struct Point {
        x: i32,
        y: i32,
    }

    let analyzer = BoxConsumer::new(|p: &Point| {
        println!("Point coordinates: ({}, {})", p.x, p.y);
    })
    .and_then(|p: &Point| {
        let distance = ((p.x * p.x + p.y * p.y) as f64).sqrt();
        println!("Distance from origin: {:.2}", distance);
    })
    .and_then(|p: &Point| {
        let quadrant = match (p.x >= 0, p.y >= 0) {
            (true, true) => "First quadrant",
            (false, true) => "Second quadrant",
            (false, false) => "Third quadrant",
            (true, false) => "Fourth quadrant",
        };
        println!("Quadrant: {}", quadrant);
    });

    let point = Point { x: 3, y: 4 };
    println!("Analyzing point: {:?}", point);
    analyzer.accept(&point);
    println!("Original point: {:?} (not modified)\n", point);

    // ========================================================================
    // Example 15: Data collection and statistics
    // ========================================================================
    println!("Example 15: Data collection and statistics");
    println!("{}", "-".repeat(50));

    let sum = Arc::new(Mutex::new(0));
    let count = Arc::new(Mutex::new(0));
    let sum_clone = sum.clone();
    let count_clone = count.clone();

    let collector = BoxConsumer::new(move |x: &i32| {
        *sum_clone.lock().unwrap() += *x;
        *count_clone.lock().unwrap() += 1;
    });

    let numbers = vec![10, 20, 30, 40, 50];
    println!("Numbers: {:?}", numbers);
    for num in &numbers {
        collector.accept(num);
    }

    let total = *sum.lock().unwrap();
    let cnt = *count.lock().unwrap();
    println!("Sum: {}", total);
    println!("Count: {}", cnt);
    println!("Average: {:.2}\n", total as f64 / cnt as f64);

    println!("=== All examples completed ===");
    println!("\nTip: For value modification functionality, please refer to mutator_demo.rs");
}

fn into_rc(self) -> RcConsumer<T>

where Self: Sized + 'static,

Convert to RcConsumer

⚠️ Consumes self: The original consumer will be unavailable after calling this method.

Returns

Returns the wrapped RcConsumer<T>

Examples found in repository

examples/consumers/consumer_demo.rs (line 366)

fn main() {
    println!("=== Consumer Examples ===\n");
    println!("Note: Consumer only reads values, does not modify the original value");
    println!("If you need to modify values, please refer to mutator_demo.rs\n");

    // ========================================================================
    // Example 1: BoxConsumer basic usage
    // ========================================================================
    println!("Example 1: BoxConsumer basic usage");
    println!("{}", "-".repeat(50));

    let consumer = BoxConsumer::new(|x: &i32| {
        println!("Read and calculate: {} * 2 = {}", x, x * 2);
    });
    let value = 5;
    println!("Value: {}", value);
    consumer.accept(&value);
    println!("Value remains: {} (not modified)\n", value);

    // ========================================================================
    // Example 2: BoxConsumer method chaining
    // ========================================================================
    println!("Example 2: BoxConsumer method chaining");
    println!("{}", "-".repeat(50));

    let results = Arc::new(Mutex::new(Vec::new()));
    let r1 = results.clone();
    let r2 = results.clone();
    let r3 = results.clone();

    let chained = BoxConsumer::new(move |x: &i32| {
        r1.lock().unwrap().push(*x * 2);
    })
    .and_then(move |x: &i32| {
        r2.lock().unwrap().push(*x + 10);
    })
    .and_then(move |x: &i32| {
        r3.lock().unwrap().push(*x);
        println!("Processing value: {}", x);
    });

    let value = 5;
    println!("Initial value: {}", value);
    chained.accept(&value);
    println!("Collected results: {:?}", *results.lock().unwrap());
    println!("Original value: {} (not modified)\n", value);

    // ========================================================================
    // Example 3: Closure extension methods
    // ========================================================================
    println!("Example 3: Direct use of extension methods on closures");
    println!("{}", "-".repeat(50));

    let result = Arc::new(Mutex::new(0));
    let r1 = result.clone();
    let r2 = result.clone();

    let closure_chain = (move |x: &i32| {
        *r1.lock().unwrap() = *x * 2;
    })
    .and_then(move |_x: &i32| {
        *r2.lock().unwrap() += 10;
    });

    let value = 5;
    println!("Initial value: {}", value);
    closure_chain.accept(&value);
    println!("Calculation result: {}", *result.lock().unwrap());
    println!("Original value: {} (not modified)\n", value);

    // ========================================================================
    // Example 4: BoxConsumer factory methods
    // ========================================================================
    println!("Example 4: BoxConsumer factory methods");
    println!("{}", "-".repeat(50));

    // noop
    println!("noop - does nothing:");
    let noop = BoxConsumer::<i32>::noop();
    let value = 42;
    noop.accept(&value);
    println!("Value: {}\n", value);

    // print
    print!("print - prints value: ");
    let print = BoxConsumer::new(|x: &i32| println!("{}", x));
    let value = 42;
    print.accept(&value);
    println!();

    // print with prefix
    let print_with = BoxConsumer::new(|x: &i32| println!("Value is: {}", x));
    let value = 42;
    print_with.accept(&value);
    println!();

    // ========================================================================
    // Example 5: Conditional Consumer
    // ========================================================================
    println!("Example 5: Conditional Consumer");
    println!("{}", "-".repeat(50));

    // when
    let mut check_positive =
        BoxStatefulConsumer::new(|x: &i32| println!("Positive: {}", x)).when(|x: &i32| *x > 0);

    let positive = 5;
    let negative = -5;
    print!("Check {}: ", positive);
    check_positive.accept(&positive);
    print!("Check {}: ", negative);
    check_positive.accept(&negative);
    println!("(negative numbers not printed)\n");

    // when().or_else()
    let mut categorize = BoxStatefulConsumer::new(|x: &i32| println!("Positive: {}", x))
        .when(|x: &i32| *x > 0)
        .or_else(|x: &i32| println!("Non-positive: {}", x));

    let positive = 10;
    let negative = -10;
    categorize.accept(&positive);
    categorize.accept(&negative);
    println!();

    // ========================================================================
    // Example 6: ArcConsumer - multi-threaded sharing
    // ========================================================================
    println!("Example 6: ArcConsumer - multi-threaded sharing");
    println!("{}", "-".repeat(50));

    let shared = ArcConsumer::new(|x: &i32| println!("Processing value: {}", x * 2));

    // Clone for another thread
    let shared_clone = shared.clone();
    let handle = thread::spawn(move || {
        let value = 5;
        let consumer = shared_clone;
        consumer.accept(&value);
        value
    });

    // Use in main thread
    let value = 3;
    let consumer = shared;
    consumer.accept(&value);

    let thread_result = handle.join().unwrap();
    println!("Thread result: {}\n", thread_result);

    // ========================================================================
    // Example 7: ArcConsumer composition (does not consume original consumer)
    // ========================================================================
    println!("Example 7: ArcConsumer composition (borrowing &self)");
    println!("{}", "-".repeat(50));

    let double = ArcConsumer::new(|x: &i32| println!("double: {}", x * 2));
    let add_ten = ArcConsumer::new(|x: &i32| println!("add_ten: {}", x + 10));

    // Composition does not consume original consumer
    let pipeline1 = double.and_then(add_ten.clone());
    let pipeline2 = add_ten.and_then(double.clone());

    let value1 = 5;
    let p1 = pipeline1;
    print!("pipeline1 processing 5: ");
    p1.accept(&value1);

    let value2 = 5;
    let p2 = pipeline2;
    print!("pipeline2 processing 5: ");
    p2.accept(&value2);

    // double and add_ten are still available
    let value3 = 10;
    let d = double;
    print!("Original double still available, processing 10: ");
    d.accept(&value3);
    println!();

    // ========================================================================
    // Example 8: RcConsumer - single-threaded sharing
    // ========================================================================
    println!("Example 8: RcConsumer - single-threaded sharing");
    println!("{}", "-".repeat(50));

    let rc_consumer = RcConsumer::new(|x: &i32| println!("Processing: {}", x * 2));

    // Clone multiple copies
    let clone1 = rc_consumer.clone();
    let clone2 = rc_consumer.clone();

    let value1 = 5;
    let c1 = clone1;
    print!("clone1 processing 5: ");
    c1.accept(&value1);

    let value2 = 3;
    let c2 = clone2;
    print!("clone2 processing 3: ");
    c2.accept(&value2);

    let value3 = 7;
    let c3 = rc_consumer;
    print!("Original processing 7: ");
    c3.accept(&value3);
    println!();

    // ========================================================================
    // Example 9: RcConsumer composition (borrowing &self)
    // ========================================================================
    println!("Example 9: RcConsumer composition (borrowing &self)");
    println!("{}", "-".repeat(50));

    let double = RcConsumer::new(|x: &i32| println!("double: {}", x * 2));
    let add_ten = RcConsumer::new(|x: &i32| println!("add_ten: {}", x + 10));

    let pipeline1 = double.and_then(add_ten.clone());
    let pipeline2 = add_ten.and_then(double.clone());

    let value1 = 5;
    let p1 = pipeline1;
    print!("pipeline1 processing 5: ");
    p1.accept(&value1);

    let value2 = 5;
    let p2 = pipeline2;
    print!("pipeline2 processing 5: ");
    p2.accept(&value2);
    println!();

    // ========================================================================
    // Example 10: Unified Consumer trait
    // ========================================================================
    println!("Example 10: Unified Consumer trait");
    println!("{}", "-".repeat(50));

    fn log_all<C: Consumer<i32>>(consumer: &mut C, values: &[i32]) {
        for value in values.iter() {
            consumer.accept(value);
        }
    }

    let values = vec![1, 2, 3, 4, 5];

    let mut box_con = BoxConsumer::new(|x: &i32| print!("{} ", x * 2));
    print!("BoxConsumer processing {:?}: ", values);
    log_all(&mut box_con, &values);
    println!();

    let mut arc_con = ArcConsumer::new(|x: &i32| print!("{} ", x * 2));
    print!("ArcConsumer processing {:?}: ", values);
    log_all(&mut arc_con, &values);
    println!();

    let mut rc_con = RcConsumer::new(|x: &i32| print!("{} ", x * 2));
    print!("RcConsumer processing {:?}: ", values);
    log_all(&mut rc_con, &values);
    println!();

    let mut closure = |x: &i32| print!("{} ", x * 2);
    print!("Closure processing {:?}: ", values);
    log_all(&mut closure, &values);
    println!("\n");

    // ========================================================================
    // Example 11: Data validation and logging
    // ========================================================================
    println!("Example 11: Data validation and logging");
    println!("{}", "-".repeat(50));

    let validator = BoxConsumer::new(|x: &i32| {
        let status = if *x >= 0 && *x <= 100 {
            "valid"
        } else {
            "out of range"
        };
        println!("Validate {}: {}", x, status);
    });

    let logger = BoxConsumer::new(|x: &i32| {
        println!("Log to file: value={}, square={}", x, x * x);
    });

    let pipeline = validator.and_then(logger);

    let test_values = vec![-50, 30, 200];
    for value in test_values {
        pipeline.accept(&value);
    }
    println!();

    // ========================================================================
    // Example 12: String analysis
    // ========================================================================
    println!("Example 12: String analysis");
    println!("{}", "-".repeat(50));

    let string_analyzer = BoxConsumer::new(|s: &String| {
        println!("Length: {}", s.len());
    })
    .and_then(|s: &String| {
        println!("Lowercase: {}", s.to_lowercase());
    })
    .and_then(|s: &String| {
        println!("Uppercase: {}", s.to_uppercase());
    })
    .and_then(|s: &String| {
        let word_count = s.split_whitespace().count();
        println!("Word count: {}", word_count);
    });

    let text = String::from("Hello World");
    println!("Analyzing text: \"{}\"", text);
    string_analyzer.accept(&text);
    println!("Original text: \"{}\" (not modified)\n", text);

    // ========================================================================
    // Example 13: Type conversion
    // ========================================================================
    println!("Example 13: Type conversion");
    println!("{}", "-".repeat(50));

    // Closure -> BoxConsumer
    let closure = |x: &i32| print!("Processing: {} ", x * 2);
    let box_con = Consumer::into_box(closure);
    let value = 5;
    print!("Closure -> BoxConsumer: ");
    box_con.accept(&value);
    println!();

    // Closure -> RcConsumer
    let closure = |x: &i32| print!("Processing: {} ", x * 2);
    let rc_con = Consumer::into_rc(closure);
    let value = 5;
    print!("Closure -> RcConsumer: ");
    rc_con.accept(&value);
    println!();

    // Closure -> ArcConsumer
    let closure = |x: &i32| print!("Processing: {} ", x * 2);
    let arc_con = Consumer::into_arc(closure);
    let value = 5;
    print!("Closure -> ArcConsumer: ");
    arc_con.accept(&value);
    println!();

    // BoxConsumer -> RcConsumer
    let box_con = BoxConsumer::new(|x: &i32| print!("Processing: {} ", x * 2));
    let rc_con = box_con.into_rc();
    let value = 5;
    print!("BoxConsumer -> RcConsumer: ");
    rc_con.accept(&value);
    println!();

    // RcConsumer -> BoxConsumer
    let rc_con = RcConsumer::new(|x: &i32| print!("Processing: {} ", x * 2));
    let box_con = rc_con.into_box();
    let value = 5;
    print!("RcConsumer -> BoxConsumer: ");
    box_con.accept(&value);
    println!("\n");

    // ========================================================================
    // Example 14: Custom types
    // ========================================================================
    println!("Example 14: Custom types");
    println!("{}", "-".repeat(50));

    #[derive(Debug, Clone)]
    struct Point {
        x: i32,
        y: i32,
    }

    let analyzer = BoxConsumer::new(|p: &Point| {
        println!("Point coordinates: ({}, {})", p.x, p.y);
    })
    .and_then(|p: &Point| {
        let distance = ((p.x * p.x + p.y * p.y) as f64).sqrt();
        println!("Distance from origin: {:.2}", distance);
    })
    .and_then(|p: &Point| {
        let quadrant = match (p.x >= 0, p.y >= 0) {
            (true, true) => "First quadrant",
            (false, true) => "Second quadrant",
            (false, false) => "Third quadrant",
            (true, false) => "Fourth quadrant",
        };
        println!("Quadrant: {}", quadrant);
    });

    let point = Point { x: 3, y: 4 };
    println!("Analyzing point: {:?}", point);
    analyzer.accept(&point);
    println!("Original point: {:?} (not modified)\n", point);

    // ========================================================================
    // Example 15: Data collection and statistics
    // ========================================================================
    println!("Example 15: Data collection and statistics");
    println!("{}", "-".repeat(50));

    let sum = Arc::new(Mutex::new(0));
    let count = Arc::new(Mutex::new(0));
    let sum_clone = sum.clone();
    let count_clone = count.clone();

    let collector = BoxConsumer::new(move |x: &i32| {
        *sum_clone.lock().unwrap() += *x;
        *count_clone.lock().unwrap() += 1;
    });

    let numbers = vec![10, 20, 30, 40, 50];
    println!("Numbers: {:?}", numbers);
    for num in &numbers {
        collector.accept(num);
    }

    let total = *sum.lock().unwrap();
    let cnt = *count.lock().unwrap();
    println!("Sum: {}", total);
    println!("Count: {}", cnt);
    println!("Average: {:.2}\n", total as f64 / cnt as f64);

    println!("=== All examples completed ===");
    println!("\nTip: For value modification functionality, please refer to mutator_demo.rs");
}

fn into_arc(self) -> ArcConsumer<T>

where Self: Sized + Send + Sync + 'static,

Convert to ArcConsumer

⚠️ Consumes self: The original consumer will be unavailable after calling this method.

Returns

Returns the wrapped ArcConsumer<T>

Examples found in repository

examples/consumers/consumer_demo.rs (line 374)

fn main() {
    println!("=== Consumer Examples ===\n");
    println!("Note: Consumer only reads values, does not modify the original value");
    println!("If you need to modify values, please refer to mutator_demo.rs\n");

    // ========================================================================
    // Example 1: BoxConsumer basic usage
    // ========================================================================
    println!("Example 1: BoxConsumer basic usage");
    println!("{}", "-".repeat(50));

    let consumer = BoxConsumer::new(|x: &i32| {
        println!("Read and calculate: {} * 2 = {}", x, x * 2);
    });
    let value = 5;
    println!("Value: {}", value);
    consumer.accept(&value);
    println!("Value remains: {} (not modified)\n", value);

    // ========================================================================
    // Example 2: BoxConsumer method chaining
    // ========================================================================
    println!("Example 2: BoxConsumer method chaining");
    println!("{}", "-".repeat(50));

    let results = Arc::new(Mutex::new(Vec::new()));
    let r1 = results.clone();
    let r2 = results.clone();
    let r3 = results.clone();

    let chained = BoxConsumer::new(move |x: &i32| {
        r1.lock().unwrap().push(*x * 2);
    })
    .and_then(move |x: &i32| {
        r2.lock().unwrap().push(*x + 10);
    })
    .and_then(move |x: &i32| {
        r3.lock().unwrap().push(*x);
        println!("Processing value: {}", x);
    });

    let value = 5;
    println!("Initial value: {}", value);
    chained.accept(&value);
    println!("Collected results: {:?}", *results.lock().unwrap());
    println!("Original value: {} (not modified)\n", value);

    // ========================================================================
    // Example 3: Closure extension methods
    // ========================================================================
    println!("Example 3: Direct use of extension methods on closures");
    println!("{}", "-".repeat(50));

    let result = Arc::new(Mutex::new(0));
    let r1 = result.clone();
    let r2 = result.clone();

    let closure_chain = (move |x: &i32| {
        *r1.lock().unwrap() = *x * 2;
    })
    .and_then(move |_x: &i32| {
        *r2.lock().unwrap() += 10;
    });

    let value = 5;
    println!("Initial value: {}", value);
    closure_chain.accept(&value);
    println!("Calculation result: {}", *result.lock().unwrap());
    println!("Original value: {} (not modified)\n", value);

    // ========================================================================
    // Example 4: BoxConsumer factory methods
    // ========================================================================
    println!("Example 4: BoxConsumer factory methods");
    println!("{}", "-".repeat(50));

    // noop
    println!("noop - does nothing:");
    let noop = BoxConsumer::<i32>::noop();
    let value = 42;
    noop.accept(&value);
    println!("Value: {}\n", value);

    // print
    print!("print - prints value: ");
    let print = BoxConsumer::new(|x: &i32| println!("{}", x));
    let value = 42;
    print.accept(&value);
    println!();

    // print with prefix
    let print_with = BoxConsumer::new(|x: &i32| println!("Value is: {}", x));
    let value = 42;
    print_with.accept(&value);
    println!();

    // ========================================================================
    // Example 5: Conditional Consumer
    // ========================================================================
    println!("Example 5: Conditional Consumer");
    println!("{}", "-".repeat(50));

    // when
    let mut check_positive =
        BoxStatefulConsumer::new(|x: &i32| println!("Positive: {}", x)).when(|x: &i32| *x > 0);

    let positive = 5;
    let negative = -5;
    print!("Check {}: ", positive);
    check_positive.accept(&positive);
    print!("Check {}: ", negative);
    check_positive.accept(&negative);
    println!("(negative numbers not printed)\n");

    // when().or_else()
    let mut categorize = BoxStatefulConsumer::new(|x: &i32| println!("Positive: {}", x))
        .when(|x: &i32| *x > 0)
        .or_else(|x: &i32| println!("Non-positive: {}", x));

    let positive = 10;
    let negative = -10;
    categorize.accept(&positive);
    categorize.accept(&negative);
    println!();

    // ========================================================================
    // Example 6: ArcConsumer - multi-threaded sharing
    // ========================================================================
    println!("Example 6: ArcConsumer - multi-threaded sharing");
    println!("{}", "-".repeat(50));

    let shared = ArcConsumer::new(|x: &i32| println!("Processing value: {}", x * 2));

    // Clone for another thread
    let shared_clone = shared.clone();
    let handle = thread::spawn(move || {
        let value = 5;
        let consumer = shared_clone;
        consumer.accept(&value);
        value
    });

    // Use in main thread
    let value = 3;
    let consumer = shared;
    consumer.accept(&value);

    let thread_result = handle.join().unwrap();
    println!("Thread result: {}\n", thread_result);

    // ========================================================================
    // Example 7: ArcConsumer composition (does not consume original consumer)
    // ========================================================================
    println!("Example 7: ArcConsumer composition (borrowing &self)");
    println!("{}", "-".repeat(50));

    let double = ArcConsumer::new(|x: &i32| println!("double: {}", x * 2));
    let add_ten = ArcConsumer::new(|x: &i32| println!("add_ten: {}", x + 10));

    // Composition does not consume original consumer
    let pipeline1 = double.and_then(add_ten.clone());
    let pipeline2 = add_ten.and_then(double.clone());

    let value1 = 5;
    let p1 = pipeline1;
    print!("pipeline1 processing 5: ");
    p1.accept(&value1);

    let value2 = 5;
    let p2 = pipeline2;
    print!("pipeline2 processing 5: ");
    p2.accept(&value2);

    // double and add_ten are still available
    let value3 = 10;
    let d = double;
    print!("Original double still available, processing 10: ");
    d.accept(&value3);
    println!();

    // ========================================================================
    // Example 8: RcConsumer - single-threaded sharing
    // ========================================================================
    println!("Example 8: RcConsumer - single-threaded sharing");
    println!("{}", "-".repeat(50));

    let rc_consumer = RcConsumer::new(|x: &i32| println!("Processing: {}", x * 2));

    // Clone multiple copies
    let clone1 = rc_consumer.clone();
    let clone2 = rc_consumer.clone();

    let value1 = 5;
    let c1 = clone1;
    print!("clone1 processing 5: ");
    c1.accept(&value1);

    let value2 = 3;
    let c2 = clone2;
    print!("clone2 processing 3: ");
    c2.accept(&value2);

    let value3 = 7;
    let c3 = rc_consumer;
    print!("Original processing 7: ");
    c3.accept(&value3);
    println!();

    // ========================================================================
    // Example 9: RcConsumer composition (borrowing &self)
    // ========================================================================
    println!("Example 9: RcConsumer composition (borrowing &self)");
    println!("{}", "-".repeat(50));

    let double = RcConsumer::new(|x: &i32| println!("double: {}", x * 2));
    let add_ten = RcConsumer::new(|x: &i32| println!("add_ten: {}", x + 10));

    let pipeline1 = double.and_then(add_ten.clone());
    let pipeline2 = add_ten.and_then(double.clone());

    let value1 = 5;
    let p1 = pipeline1;
    print!("pipeline1 processing 5: ");
    p1.accept(&value1);

    let value2 = 5;
    let p2 = pipeline2;
    print!("pipeline2 processing 5: ");
    p2.accept(&value2);
    println!();

    // ========================================================================
    // Example 10: Unified Consumer trait
    // ========================================================================
    println!("Example 10: Unified Consumer trait");
    println!("{}", "-".repeat(50));

    fn log_all<C: Consumer<i32>>(consumer: &mut C, values: &[i32]) {
        for value in values.iter() {
            consumer.accept(value);
        }
    }

    let values = vec![1, 2, 3, 4, 5];

    let mut box_con = BoxConsumer::new(|x: &i32| print!("{} ", x * 2));
    print!("BoxConsumer processing {:?}: ", values);
    log_all(&mut box_con, &values);
    println!();

    let mut arc_con = ArcConsumer::new(|x: &i32| print!("{} ", x * 2));
    print!("ArcConsumer processing {:?}: ", values);
    log_all(&mut arc_con, &values);
    println!();

    let mut rc_con = RcConsumer::new(|x: &i32| print!("{} ", x * 2));
    print!("RcConsumer processing {:?}: ", values);
    log_all(&mut rc_con, &values);
    println!();

    let mut closure = |x: &i32| print!("{} ", x * 2);
    print!("Closure processing {:?}: ", values);
    log_all(&mut closure, &values);
    println!("\n");

    // ========================================================================
    // Example 11: Data validation and logging
    // ========================================================================
    println!("Example 11: Data validation and logging");
    println!("{}", "-".repeat(50));

    let validator = BoxConsumer::new(|x: &i32| {
        let status = if *x >= 0 && *x <= 100 {
            "valid"
        } else {
            "out of range"
        };
        println!("Validate {}: {}", x, status);
    });

    let logger = BoxConsumer::new(|x: &i32| {
        println!("Log to file: value={}, square={}", x, x * x);
    });

    let pipeline = validator.and_then(logger);

    let test_values = vec![-50, 30, 200];
    for value in test_values {
        pipeline.accept(&value);
    }
    println!();

    // ========================================================================
    // Example 12: String analysis
    // ========================================================================
    println!("Example 12: String analysis");
    println!("{}", "-".repeat(50));

    let string_analyzer = BoxConsumer::new(|s: &String| {
        println!("Length: {}", s.len());
    })
    .and_then(|s: &String| {
        println!("Lowercase: {}", s.to_lowercase());
    })
    .and_then(|s: &String| {
        println!("Uppercase: {}", s.to_uppercase());
    })
    .and_then(|s: &String| {
        let word_count = s.split_whitespace().count();
        println!("Word count: {}", word_count);
    });

    let text = String::from("Hello World");
    println!("Analyzing text: \"{}\"", text);
    string_analyzer.accept(&text);
    println!("Original text: \"{}\" (not modified)\n", text);

    // ========================================================================
    // Example 13: Type conversion
    // ========================================================================
    println!("Example 13: Type conversion");
    println!("{}", "-".repeat(50));

    // Closure -> BoxConsumer
    let closure = |x: &i32| print!("Processing: {} ", x * 2);
    let box_con = Consumer::into_box(closure);
    let value = 5;
    print!("Closure -> BoxConsumer: ");
    box_con.accept(&value);
    println!();

    // Closure -> RcConsumer
    let closure = |x: &i32| print!("Processing: {} ", x * 2);
    let rc_con = Consumer::into_rc(closure);
    let value = 5;
    print!("Closure -> RcConsumer: ");
    rc_con.accept(&value);
    println!();

    // Closure -> ArcConsumer
    let closure = |x: &i32| print!("Processing: {} ", x * 2);
    let arc_con = Consumer::into_arc(closure);
    let value = 5;
    print!("Closure -> ArcConsumer: ");
    arc_con.accept(&value);
    println!();

    // BoxConsumer -> RcConsumer
    let box_con = BoxConsumer::new(|x: &i32| print!("Processing: {} ", x * 2));
    let rc_con = box_con.into_rc();
    let value = 5;
    print!("BoxConsumer -> RcConsumer: ");
    rc_con.accept(&value);
    println!();

    // RcConsumer -> BoxConsumer
    let rc_con = RcConsumer::new(|x: &i32| print!("Processing: {} ", x * 2));
    let box_con = rc_con.into_box();
    let value = 5;
    print!("RcConsumer -> BoxConsumer: ");
    box_con.accept(&value);
    println!("\n");

    // ========================================================================
    // Example 14: Custom types
    // ========================================================================
    println!("Example 14: Custom types");
    println!("{}", "-".repeat(50));

    #[derive(Debug, Clone)]
    struct Point {
        x: i32,
        y: i32,
    }

    let analyzer = BoxConsumer::new(|p: &Point| {
        println!("Point coordinates: ({}, {})", p.x, p.y);
    })
    .and_then(|p: &Point| {
        let distance = ((p.x * p.x + p.y * p.y) as f64).sqrt();
        println!("Distance from origin: {:.2}", distance);
    })
    .and_then(|p: &Point| {
        let quadrant = match (p.x >= 0, p.y >= 0) {
            (true, true) => "First quadrant",
            (false, true) => "Second quadrant",
            (false, false) => "Third quadrant",
            (true, false) => "Fourth quadrant",
        };
        println!("Quadrant: {}", quadrant);
    });

    let point = Point { x: 3, y: 4 };
    println!("Analyzing point: {:?}", point);
    analyzer.accept(&point);
    println!("Original point: {:?} (not modified)\n", point);

    // ========================================================================
    // Example 15: Data collection and statistics
    // ========================================================================
    println!("Example 15: Data collection and statistics");
    println!("{}", "-".repeat(50));

    let sum = Arc::new(Mutex::new(0));
    let count = Arc::new(Mutex::new(0));
    let sum_clone = sum.clone();
    let count_clone = count.clone();

    let collector = BoxConsumer::new(move |x: &i32| {
        *sum_clone.lock().unwrap() += *x;
        *count_clone.lock().unwrap() += 1;
    });

    let numbers = vec![10, 20, 30, 40, 50];
    println!("Numbers: {:?}", numbers);
    for num in &numbers {
        collector.accept(num);
    }

    let total = *sum.lock().unwrap();
    let cnt = *count.lock().unwrap();
    println!("Sum: {}", total);
    println!("Count: {}", cnt);
    println!("Average: {:.2}\n", total as f64 / cnt as f64);

    println!("=== All examples completed ===");
    println!("\nTip: For value modification functionality, please refer to mutator_demo.rs");
}

fn into_fn(self) -> impl Fn(&T)

where Self: Sized + 'static,

Convert to closure

⚠️ Consumes self: The original consumer will be unavailable after calling this method.

Converts a non-mutating consumer to a closure that can be used directly in places where the standard library requires Fn.

Returns

Returns a closure implementing Fn(&T)

Examples

use qubit_function::{Consumer, BoxConsumer};

let consumer = BoxConsumer::new(|x: &i32| {
    println!("Value: {}", x);
});
let func = consumer.into_fn();
func(&5);

Examples found in repository

examples/consumers/consumer_fn_usage.rs (line 36)

fn main() {
    println!("=== Consumer into_fn/to_fn Usage Examples ===\n");

    // Example 1: Using BoxConsumer::into_fn to pass to standard library's map
    println!("1. BoxConsumer::into_fn used with Iterator::for_each");
    let log = Arc::new(Mutex::new(Vec::new()));
    let l = log.clone();
    let consumer = BoxConsumer::new(move |x: &i32| {
        l.lock().unwrap().push(*x * 2);
    });

    // Convert consumer to closure and pass to for_each
    [1, 2, 3, 4, 5].iter().for_each(consumer.into_fn());
    println!("   Result: {:?}\n", *log.lock().unwrap());

    // Example 2: Using ArcConsumer::to_fn can be used multiple times
    println!("2. ArcConsumer::to_fn can be used multiple times");
    let log2 = Arc::new(Mutex::new(Vec::new()));
    let l2 = log2.clone();
    let consumer2 = ArcConsumer::new(move |x: &i32| {
        l2.lock().unwrap().push(*x + 10);
    });

    // to_fn doesn't consume consumer, can be called multiple times
    [1, 2, 3].iter().for_each(consumer2.to_fn());
    println!("   First time: {:?}", *log2.lock().unwrap());

    [4, 5].iter().for_each(consumer2.to_fn());
    println!("   Second time: {:?}\n", *log2.lock().unwrap());

    // Example 3: Using RcConsumer::to_fn
    println!("3. RcConsumer::to_fn used for single-threaded scenarios");
    let log3 = Rc::new(RefCell::new(Vec::new()));
    let l3 = log3.clone();
    let consumer3 = RcConsumer::new(move |x: &i32| {
        l3.borrow_mut().push(*x * 3);
    });

    [1, 2, 3, 4].iter().for_each(consumer3.to_fn());
    println!("   Result: {:?}\n", *log3.borrow());

    // Example 4: Using in custom functions
    println!("4. Using in custom functions");
    fn process_items<F>(items: Vec<i32>, consumer: F)
    where
        F: FnMut(&i32),
    {
        items.iter().for_each(consumer);
    }

    let log4 = Arc::new(Mutex::new(Vec::new()));
    let l4 = log4.clone();
    let consumer4 = BoxConsumer::new(move |x: &i32| {
        l4.lock().unwrap().push(*x * 5);
    });

    // Use into_fn to convert Consumer to closure and pass to function
    process_items(vec![1, 2, 3], consumer4.into_fn());
    println!("   Result: {:?}\n", *log4.lock().unwrap());

    // Example 5: Using into_fn after chained operations
    println!("5. Using into_fn after chained operations");
    let log5 = Arc::new(Mutex::new(Vec::new()));
    let l5 = log5.clone();
    let l6 = log5.clone();

    let chained = BoxConsumer::new(move |x: &i32| {
        l5.lock().unwrap().push(format!("A: {}", x));
    })
    .and_then(move |x: &i32| {
        l6.lock().unwrap().push(format!("B: {}", x));
    });

    [1, 2].iter().for_each(chained.into_fn());
    println!("   Result: {:?}\n", *log5.lock().unwrap());

    println!("=== Demo Complete ===");
}

fn into_once(self) -> BoxConsumerOnce<T>

where Self: Sized + 'static,

Convert to ConsumerOnce

⚠️ Consumes self: The original consumer will be unavailable after calling this method.

Converts a reusable non-mutating consumer to a one-time consumer that consumes itself on use. This enables passing Consumer to functions that require ConsumerOnce.

Returns

Returns a BoxConsumerOnce<T>

Examples

use qubit_function::{Consumer, ConsumerOnce, BoxConsumer};

fn takes_once<C: ConsumerOnce<i32>>(consumer: C, value: &i32) {
    consumer.accept(value);
}

let consumer = BoxConsumer::new(|x: &i32| println!("{}", x));
takes_once(consumer.into_once(), &5);

fn to_box(&self) -> BoxConsumer<T>

where Self: Clone + 'static,

Non-consuming conversion to BoxConsumer

⚠️ Does NOT consume self: This method clones self and returns a boxed non-mutating consumer that calls the cloned consumer. Requires Self: Clone so it can be called through an immutable reference.

Returns

Returns the wrapped BoxConsumer<T>

fn to_rc(&self) -> RcConsumer<T>

where Self: Clone + 'static,

Non-consuming conversion to RcConsumer

⚠️ Does NOT consume self: Clones self and returns an RcConsumer that forwards to the cloned consumer. Requires Self: Clone.

Returns

Returns the wrapped RcConsumer<T>

fn to_arc(&self) -> ArcConsumer<T>

where Self: Clone + Send + Sync + 'static,

Non-consuming conversion to ArcConsumer

⚠️ Does NOT consume self: Clones self and returns an ArcConsumer. Requires Self: Clone + Send + Sync so the result is thread-safe.

Returns

Returns the wrapped ArcConsumer<T>

fn to_fn(&self) -> impl Fn(&T)

where Self: Clone + 'static,

Non-consuming conversion to a boxed closure

⚠️ Does NOT consume self: Returns a closure which calls a cloned copy of the consumer. Requires Self: Clone.

Returns

Returns a closure implementing Fn(&T) which forwards to the cloned consumer.

Examples found in repository

examples/consumers/consumer_fn_usage.rs (line 48)

fn main() {
    println!("=== Consumer into_fn/to_fn Usage Examples ===\n");

    // Example 1: Using BoxConsumer::into_fn to pass to standard library's map
    println!("1. BoxConsumer::into_fn used with Iterator::for_each");
    let log = Arc::new(Mutex::new(Vec::new()));
    let l = log.clone();
    let consumer = BoxConsumer::new(move |x: &i32| {
        l.lock().unwrap().push(*x * 2);
    });

    // Convert consumer to closure and pass to for_each
    [1, 2, 3, 4, 5].iter().for_each(consumer.into_fn());
    println!("   Result: {:?}\n", *log.lock().unwrap());

    // Example 2: Using ArcConsumer::to_fn can be used multiple times
    println!("2. ArcConsumer::to_fn can be used multiple times");
    let log2 = Arc::new(Mutex::new(Vec::new()));
    let l2 = log2.clone();
    let consumer2 = ArcConsumer::new(move |x: &i32| {
        l2.lock().unwrap().push(*x + 10);
    });

    // to_fn doesn't consume consumer, can be called multiple times
    [1, 2, 3].iter().for_each(consumer2.to_fn());
    println!("   First time: {:?}", *log2.lock().unwrap());

    [4, 5].iter().for_each(consumer2.to_fn());
    println!("   Second time: {:?}\n", *log2.lock().unwrap());

    // Example 3: Using RcConsumer::to_fn
    println!("3. RcConsumer::to_fn used for single-threaded scenarios");
    let log3 = Rc::new(RefCell::new(Vec::new()));
    let l3 = log3.clone();
    let consumer3 = RcConsumer::new(move |x: &i32| {
        l3.borrow_mut().push(*x * 3);
    });

    [1, 2, 3, 4].iter().for_each(consumer3.to_fn());
    println!("   Result: {:?}\n", *log3.borrow());

    // Example 4: Using in custom functions
    println!("4. Using in custom functions");
    fn process_items<F>(items: Vec<i32>, consumer: F)
    where
        F: FnMut(&i32),
    {
        items.iter().for_each(consumer);
    }

    let log4 = Arc::new(Mutex::new(Vec::new()));
    let l4 = log4.clone();
    let consumer4 = BoxConsumer::new(move |x: &i32| {
        l4.lock().unwrap().push(*x * 5);
    });

    // Use into_fn to convert Consumer to closure and pass to function
    process_items(vec![1, 2, 3], consumer4.into_fn());
    println!("   Result: {:?}\n", *log4.lock().unwrap());

    // Example 5: Using into_fn after chained operations
    println!("5. Using into_fn after chained operations");
    let log5 = Arc::new(Mutex::new(Vec::new()));
    let l5 = log5.clone();
    let l6 = log5.clone();

    let chained = BoxConsumer::new(move |x: &i32| {
        l5.lock().unwrap().push(format!("A: {}", x));
    })
    .and_then(move |x: &i32| {
        l6.lock().unwrap().push(format!("B: {}", x));
    });

    [1, 2].iter().for_each(chained.into_fn());
    println!("   Result: {:?}\n", *log5.lock().unwrap());

    println!("=== Demo Complete ===");
}

fn to_once(&self) -> BoxConsumerOnce<T>

where Self: Clone + 'static,

Convert to ConsumerOnce without consuming self

⚠️ Requires Clone: This method requires Self to implement Clone. Clones the current consumer and converts the clone to a one-time consumer.

Returns

Returns a BoxConsumerOnce<T>

Examples

use qubit_function::{Consumer, ConsumerOnce, ArcConsumer};

fn takes_once<C: ConsumerOnce<i32>>(consumer: C, value: &i32) {
    consumer.accept(value);
}

let consumer = ArcConsumer::new(|x: &i32| println!("{}", x));
takes_once(consumer.to_once(), &5);

Implementors

impl<T> Consumer<T> for ArcConditionalConsumer<T>

impl<T> Consumer<T> for ArcConsumer<T>

impl<T> Consumer<T> for BoxConditionalConsumer<T>

impl<T> Consumer<T> for BoxConsumer<T>

impl<T> Consumer<T> for RcConditionalConsumer<T>

impl<T> Consumer<T> for RcConsumer<T>

impl<T, F> Consumer<T> for F

where F: Fn(&T),