Struct RcPredicate 

pub struct RcPredicate<T> { /* private fields */ }

An Rc-based predicate with single-threaded shared ownership.

This type is suitable for scenarios where the predicate needs to be reused in a single-threaded context. Composition methods borrow &self, allowing the original predicate to remain usable after composition.

Examples

use prism3_function::predicate::{Predicate, RcPredicate};

let pred = RcPredicate::new(|x: &i32| *x > 0);
assert!(pred.test(&5));

// Original predicate remains usable after composition
let combined = pred.and(RcPredicate::new(|x| x % 2 == 0));
assert!(pred.test(&5));  // Still works

Author

Haixing Hu

Implementations

impl<T: 'static> RcPredicate<T>

pub fn new<F>(f: F) -> Self

where F: Fn(&T) -> bool + 'static,

Creates a new RcPredicate from a closure.

Parameters

• f - The closure to wrap.

Returns

A new RcPredicate instance.

Examples found in repository

examples/predicate_fn_mut_demo.rs (line 41)

fn demo_with_vec_retain() {
    println!("2. Using Vec::retain");

    // RcPredicate example
    let pred = RcPredicate::new(|x: &i32| *x % 2 == 0);
    let mut numbers = vec![1, 2, 3, 4, 5, 6];
    println!("   Original data: {:?}", numbers);
    numbers.retain(pred.to_fn());
    println!("   Retained even numbers: {:?}", numbers);
    assert_eq!(numbers, vec![2, 4, 6]);

    // Original predicate is still available
    assert!(pred.test(&10));
    println!("   ✓ RcPredicate::to_fn() can be used in retain");
    println!("   ✓ Original predicate is still available\n");
}

/// Demonstrates usage with generic functions that require FnMut
fn demo_with_generic_function() {
    println!("3. Using generic functions (requires FnMut)");

    fn count_matching<F>(items: &[i32], mut predicate: F) -> usize
    where
        F: FnMut(&i32) -> bool,
    {
        items.iter().filter(|x| predicate(x)).count()
    }

    let pred = RcPredicate::new(|x: &i32| *x > 10);
    let count1 = count_matching(&[5, 15, 8, 20], pred.to_fn());
    println!("   First call: count = {}", count1);
    assert_eq!(count1, 2);

    // Original predicate can be reused
    let count2 = count_matching(&[12, 3, 18], pred.to_fn());
    println!("   Second call: count = {}", count2);
    assert_eq!(count2, 2);

    println!("   ✓ RcPredicate::to_fn() can be passed to generic functions requiring FnMut");
    println!("   ✓ Original predicate can be converted and used multiple times\n");
}

examples/predicate_set_name_demo.rs (line 60)

fn demo_rc_predicate() {
    println!("2. RcPredicate Naming Functionality");

    // Using new_with_name
    let pred1 = RcPredicate::new_with_name("greater_than_10", |x: &i32| *x > 10);
    println!("   Using new_with_name:");
    println!("     Name: {:?}", pred1.name());
    println!("     Test 15: {}", pred1.test(&15));

    // Using set_name
    let mut pred2 = RcPredicate::new(|x: &i32| *x < 100);
    println!("\n   Using set_name:");
    println!("     Initial name: {:?}", pred2.name());
    pred2.set_name("less_than_100");
    println!("     Name after setting: {:?}", pred2.name());
    println!("     Test 50: {}", pred2.test(&50));

    // Name is preserved after cloning
    let pred3 = pred2.clone();
    println!("\n   Name preserved after cloning:");
    println!("     Cloned name: {:?}", pred3.name());
    println!("     Test 80: {}\n", pred3.test(&80));
}

examples/predicate_demo.rs (line 103)

fn rc_predicate_examples() {
    println!("--- 3. RcPredicate Examples (Single-threaded Reuse) ---");

    let is_positive = RcPredicate::new(|x: &i32| *x > 0);
    let is_even = RcPredicate::new(|x: &i32| x % 2 == 0);

    // Multiple compositions without consuming the original
    let positive_and_even = is_positive.and(is_even.clone());
    let positive_or_even = is_positive.or(is_even.clone());

    println!("Original predicates still available:");
    println!("  is_positive.test(&5) = {}", is_positive.test(&5));
    println!("  is_even.test(&4) = {}", is_even.test(&4));

    println!("Combined predicates:");
    println!(
        "  positive_and_even.test(&4) = {}",
        positive_and_even.test(&4)
    );
    println!(
        "  positive_or_even.test(&5) = {}",
        positive_or_even.test(&5)
    );

    // Cloning
    let cloned = is_positive.clone();
    println!("Cloned predicate: {}", cloned.test(&10));
}

/// ArcPredicate examples - multi-threaded scenarios
fn arc_predicate_examples() {
    println!("--- 4. ArcPredicate Examples (Multi-threaded Scenarios) ---");

    let is_positive = ArcPredicate::new(|x: &i32| *x > 0);
    let is_even = ArcPredicate::new(|x: &i32| x % 2 == 0);

    // Create combined predicate
    let combined = is_positive.and(is_even);

    // Use in multiple threads
    let handles: Vec<_> = (0..3)
        .map(|i| {
            let pred = combined.clone();
            std::thread::spawn(move || {
                let value = i * 2;
                println!("  Thread {} testing {}: {}", i, value, pred.test(&value));
            })
        })
        .collect();

    for handle in handles {
        handle.join().unwrap();
    }

    // Original predicates still usable
    println!("Original predicates still available in main thread:");
    println!("  is_positive.test(&5) = {}", is_positive.test(&5));
}

/// Logical composition examples
fn logical_composition_examples() {
    println!("--- 5. Logical Composition Examples ---");

    let positive = RcPredicate::new_with_name("positive", |x: &i32| *x > 0);
    let even = RcPredicate::new_with_name("even", |x: &i32| x % 2 == 0);
    let less_than_ten = RcPredicate::new_with_name("less_than_ten", |x: &i32| *x < 10);

    // AND composition
    let positive_and_even = positive.and(even.clone());
    println!("positive AND even: name={:?}", positive_and_even.name());
    println!("  Test 4: {}", positive_and_even.test(&4));
    println!("  Test 5: {}", positive_and_even.test(&5));

    // OR composition
    let positive_or_even = positive.or(even.clone());
    println!("positive OR even: name={:?}", positive_or_even.name());
    println!("  Test -2: {}", positive_or_even.test(&-2));
    println!("  Test 5: {}", positive_or_even.test(&5));

    // NOT composition
    let not_positive = positive.not();
    println!("NOT positive: name={:?}", not_positive.name());
    println!("  Test 5: {}", not_positive.test(&5));
    println!("  Test -3: {}", not_positive.test(&-3));

    // NAND composition
    let nand = positive.nand(even.clone());
    println!("positive NAND even: name={:?}", nand.name());
    println!("  Test 3: {}", nand.test(&3)); // true NAND false = true
    println!("  Test 4: {}", nand.test(&4)); // true NAND true = false

    // XOR composition
    let xor = positive.xor(even.clone());
    println!("positive XOR even: name={:?}", xor.name());
    println!("  Test 3: {}", xor.test(&3)); // true XOR false = true
    println!("  Test 4: {}", xor.test(&4)); // true XOR true = false
    println!("  Test -2: {}", xor.test(&-2)); // false XOR true = true

    // NOR composition
    let nor = positive.nor(even.clone());
    println!("positive NOR even: name={:?}", nor.name());
    println!("  Test -3: {}", nor.test(&-3)); // false NOR false = true
    println!("  Test 3: {}", nor.test(&3)); // true NOR false = false
    println!("  Test -2: {}", nor.test(&-2)); // false NOR true = false
    println!("  Test 4: {}", nor.test(&4)); // true NOR true = false

    // Complex composition
    let complex = positive.and(even.clone()).and(less_than_ten.clone());
    println!("Complex composition: name={:?}", complex.name());
    println!("  Test 4: {}", complex.test(&4));
    println!("  Test 12: {}", complex.test(&12));
}

/// Interior mutability examples
fn interior_mutability_examples() {
    println!("--- 6. Interior Mutability Examples ---");

    // BoxPredicate with counter (RefCell)
    println!("BoxPredicate with counter:");
    let count = RefCell::new(0);
    let pred = BoxPredicate::new(move |x: &i32| {
        *count.borrow_mut() += 1;
        *x > 0
    });
    println!("  Test 5: {}", pred.test(&5));
    println!("  Test -3: {}", pred.test(&-3));
    println!("  Test 10: {}", pred.test(&10));
    // Note: count is moved into the closure, so we can't access it here

    // RcPredicate with cache (RefCell + HashMap)
    println!("\nRcPredicate with cache:");
    let cache: RefCell<HashMap<i32, bool>> = RefCell::new(HashMap::new());
    let expensive_pred = RcPredicate::new(move |x: &i32| {
        let mut c = cache.borrow_mut();
        *c.entry(*x).or_insert_with(|| {
            println!("    Computing result for {} (expensive operation)", x);
            *x > 0 && x % 2 == 0
        })
    });

    println!("  First test 4:");
    println!("    Result: {}", expensive_pred.test(&4));
    println!("  Test 4 again (using cache):");
    println!("    Result: {}", expensive_pred.test(&4));
    println!("  Test 3:");
    println!("    Result: {}", expensive_pred.test(&3));

    // ArcPredicate with thread-safe counter (Mutex)
    println!("\nArcPredicate with thread-safe counter:");
    let counter = Arc::new(Mutex::new(0));
    let pred = ArcPredicate::new({
        let counter = Arc::clone(&counter);
        move |x: &i32| {
            let mut c = counter.lock().unwrap();
            *c += 1;
            *x > 0
        }
    });

    let pred_clone = pred.clone();
    let counter_clone = Arc::clone(&counter);

    let handle = std::thread::spawn(move || {
        pred_clone.test(&5);
        pred_clone.test(&10);
    });

    pred.test(&3);
    handle.join().unwrap();

    println!("  Total call count: {}", counter_clone.lock().unwrap());
}

/// Practical use cases
fn practical_use_cases() {
    println!("--- 7. Practical Use Cases ---");

    // Validation rules
    println!("Scenario 1: Form Validation");
    struct User {
        name: String,
        age: i32,
        email: String,
    }

    let name_valid =
        RcPredicate::new_with_name("name_not_empty", |user: &User| !user.name.is_empty());

    let age_valid = RcPredicate::new_with_name("age_between_18_120", |user: &User| {
        user.age >= 18 && user.age <= 120
    });

    let email_valid =
        RcPredicate::new_with_name("email_contains_at", |user: &User| user.email.contains('@'));

    let all_valid = name_valid.and(age_valid.clone()).and(email_valid.clone());

    let user1 = User {
        name: "Alice".to_string(),
        age: 25,
        email: "alice@example.com".to_string(),
    };

    let user2 = User {
        name: "".to_string(),
        age: 25,
        email: "bob@example.com".to_string(),
    };

    println!("  user1 validation: {}", all_valid.test(&user1));
    println!("  user2 validation: {}", all_valid.test(&user2));

    // Filter pipeline
    println!("\nScenario 2: Data Filtering Pipeline");
    let numbers: Vec<i32> = (-10..=10).collect();

    let positive = |x: &i32| *x > 0;
    let even = |x: &i32| x % 2 == 0;
    let less_than_eight = |x: &i32| *x < 8;

    let filtered: Vec<i32> = numbers
        .iter()
        .filter(|x| positive.test(x))
        .filter(|x| even.test(x))
        .filter(|x| less_than_eight.test(x))
        .copied()
        .collect();

    println!("  Filtered numbers: {:?}", filtered);

    // Strategy pattern
    println!("\nScenario 3: Strategy Pattern");
    let mut strategies: HashMap<&str, RcPredicate<i32>> = HashMap::new();
    strategies.insert("positive", RcPredicate::new(|x: &i32| *x > 0));
    strategies.insert("negative", RcPredicate::new(|x: &i32| *x < 0));
    strategies.insert("even", RcPredicate::new(|x: &i32| x % 2 == 0));

    let test_value = 4;
    for (name, pred) in strategies.iter() {
        println!(
            "  {} strategy test {}: {}",
            name,
            test_value,
            pred.test(&test_value)
        );
    }
}

pub fn new_with_name<F>(name: &str, f: F) -> Self

where F: Fn(&T) -> bool + 'static,

Creates a named RcPredicate from a closure.

Parameters

• name - The name for this predicate.
• f - The closure to wrap.

Returns

A new named RcPredicate instance.

Examples found in repository

examples/predicate_set_name_demo.rs (line 54)

fn demo_rc_predicate() {
    println!("2. RcPredicate Naming Functionality");

    // Using new_with_name
    let pred1 = RcPredicate::new_with_name("greater_than_10", |x: &i32| *x > 10);
    println!("   Using new_with_name:");
    println!("     Name: {:?}", pred1.name());
    println!("     Test 15: {}", pred1.test(&15));

    // Using set_name
    let mut pred2 = RcPredicate::new(|x: &i32| *x < 100);
    println!("\n   Using set_name:");
    println!("     Initial name: {:?}", pred2.name());
    pred2.set_name("less_than_100");
    println!("     Name after setting: {:?}", pred2.name());
    println!("     Test 50: {}", pred2.test(&50));

    // Name is preserved after cloning
    let pred3 = pred2.clone();
    println!("\n   Name preserved after cloning:");
    println!("     Cloned name: {:?}", pred3.name());
    println!("     Test 80: {}\n", pred3.test(&80));
}

examples/predicate_demo.rs (line 163)

fn logical_composition_examples() {
    println!("--- 5. Logical Composition Examples ---");

    let positive = RcPredicate::new_with_name("positive", |x: &i32| *x > 0);
    let even = RcPredicate::new_with_name("even", |x: &i32| x % 2 == 0);
    let less_than_ten = RcPredicate::new_with_name("less_than_ten", |x: &i32| *x < 10);

    // AND composition
    let positive_and_even = positive.and(even.clone());
    println!("positive AND even: name={:?}", positive_and_even.name());
    println!("  Test 4: {}", positive_and_even.test(&4));
    println!("  Test 5: {}", positive_and_even.test(&5));

    // OR composition
    let positive_or_even = positive.or(even.clone());
    println!("positive OR even: name={:?}", positive_or_even.name());
    println!("  Test -2: {}", positive_or_even.test(&-2));
    println!("  Test 5: {}", positive_or_even.test(&5));

    // NOT composition
    let not_positive = positive.not();
    println!("NOT positive: name={:?}", not_positive.name());
    println!("  Test 5: {}", not_positive.test(&5));
    println!("  Test -3: {}", not_positive.test(&-3));

    // NAND composition
    let nand = positive.nand(even.clone());
    println!("positive NAND even: name={:?}", nand.name());
    println!("  Test 3: {}", nand.test(&3)); // true NAND false = true
    println!("  Test 4: {}", nand.test(&4)); // true NAND true = false

    // XOR composition
    let xor = positive.xor(even.clone());
    println!("positive XOR even: name={:?}", xor.name());
    println!("  Test 3: {}", xor.test(&3)); // true XOR false = true
    println!("  Test 4: {}", xor.test(&4)); // true XOR true = false
    println!("  Test -2: {}", xor.test(&-2)); // false XOR true = true

    // NOR composition
    let nor = positive.nor(even.clone());
    println!("positive NOR even: name={:?}", nor.name());
    println!("  Test -3: {}", nor.test(&-3)); // false NOR false = true
    println!("  Test 3: {}", nor.test(&3)); // true NOR false = false
    println!("  Test -2: {}", nor.test(&-2)); // false NOR true = false
    println!("  Test 4: {}", nor.test(&4)); // true NOR true = false

    // Complex composition
    let complex = positive.and(even.clone()).and(less_than_ten.clone());
    println!("Complex composition: name={:?}", complex.name());
    println!("  Test 4: {}", complex.test(&4));
    println!("  Test 12: {}", complex.test(&12));
}

/// Interior mutability examples
fn interior_mutability_examples() {
    println!("--- 6. Interior Mutability Examples ---");

    // BoxPredicate with counter (RefCell)
    println!("BoxPredicate with counter:");
    let count = RefCell::new(0);
    let pred = BoxPredicate::new(move |x: &i32| {
        *count.borrow_mut() += 1;
        *x > 0
    });
    println!("  Test 5: {}", pred.test(&5));
    println!("  Test -3: {}", pred.test(&-3));
    println!("  Test 10: {}", pred.test(&10));
    // Note: count is moved into the closure, so we can't access it here

    // RcPredicate with cache (RefCell + HashMap)
    println!("\nRcPredicate with cache:");
    let cache: RefCell<HashMap<i32, bool>> = RefCell::new(HashMap::new());
    let expensive_pred = RcPredicate::new(move |x: &i32| {
        let mut c = cache.borrow_mut();
        *c.entry(*x).or_insert_with(|| {
            println!("    Computing result for {} (expensive operation)", x);
            *x > 0 && x % 2 == 0
        })
    });

    println!("  First test 4:");
    println!("    Result: {}", expensive_pred.test(&4));
    println!("  Test 4 again (using cache):");
    println!("    Result: {}", expensive_pred.test(&4));
    println!("  Test 3:");
    println!("    Result: {}", expensive_pred.test(&3));

    // ArcPredicate with thread-safe counter (Mutex)
    println!("\nArcPredicate with thread-safe counter:");
    let counter = Arc::new(Mutex::new(0));
    let pred = ArcPredicate::new({
        let counter = Arc::clone(&counter);
        move |x: &i32| {
            let mut c = counter.lock().unwrap();
            *c += 1;
            *x > 0
        }
    });

    let pred_clone = pred.clone();
    let counter_clone = Arc::clone(&counter);

    let handle = std::thread::spawn(move || {
        pred_clone.test(&5);
        pred_clone.test(&10);
    });

    pred.test(&3);
    handle.join().unwrap();

    println!("  Total call count: {}", counter_clone.lock().unwrap());
}

/// Practical use cases
fn practical_use_cases() {
    println!("--- 7. Practical Use Cases ---");

    // Validation rules
    println!("Scenario 1: Form Validation");
    struct User {
        name: String,
        age: i32,
        email: String,
    }

    let name_valid =
        RcPredicate::new_with_name("name_not_empty", |user: &User| !user.name.is_empty());

    let age_valid = RcPredicate::new_with_name("age_between_18_120", |user: &User| {
        user.age >= 18 && user.age <= 120
    });

    let email_valid =
        RcPredicate::new_with_name("email_contains_at", |user: &User| user.email.contains('@'));

    let all_valid = name_valid.and(age_valid.clone()).and(email_valid.clone());

    let user1 = User {
        name: "Alice".to_string(),
        age: 25,
        email: "alice@example.com".to_string(),
    };

    let user2 = User {
        name: "".to_string(),
        age: 25,
        email: "bob@example.com".to_string(),
    };

    println!("  user1 validation: {}", all_valid.test(&user1));
    println!("  user2 validation: {}", all_valid.test(&user2));

    // Filter pipeline
    println!("\nScenario 2: Data Filtering Pipeline");
    let numbers: Vec<i32> = (-10..=10).collect();

    let positive = |x: &i32| *x > 0;
    let even = |x: &i32| x % 2 == 0;
    let less_than_eight = |x: &i32| *x < 8;

    let filtered: Vec<i32> = numbers
        .iter()
        .filter(|x| positive.test(x))
        .filter(|x| even.test(x))
        .filter(|x| less_than_eight.test(x))
        .copied()
        .collect();

    println!("  Filtered numbers: {:?}", filtered);

    // Strategy pattern
    println!("\nScenario 3: Strategy Pattern");
    let mut strategies: HashMap<&str, RcPredicate<i32>> = HashMap::new();
    strategies.insert("positive", RcPredicate::new(|x: &i32| *x > 0));
    strategies.insert("negative", RcPredicate::new(|x: &i32| *x < 0));
    strategies.insert("even", RcPredicate::new(|x: &i32| x % 2 == 0));

    let test_value = 4;
    for (name, pred) in strategies.iter() {
        println!(
            "  {} strategy test {}: {}",
            name,
            test_value,
            pred.test(&test_value)
        );
    }
}

pub fn always_true() -> Self

Creates a predicate that always returns true.

Returns

A new RcPredicate that always returns true.

Examples

use prism3_function::predicate::{Predicate, RcPredicate};

let pred: RcPredicate<i32> = RcPredicate::always_true();
assert!(pred.test(&42));
assert!(pred.test(&-1));
assert!(pred.test(&0));

Examples found in repository

examples/always_predicate_demo.rs (line 33)

fn main() {
    println!("=== BoxPredicate always_true/always_false Demo ===\n");

    // BoxPredicate::always_true
    let always_true: BoxPredicate<i32> = BoxPredicate::always_true();
    println!("BoxPredicate::always_true():");
    println!("  test(&42): {}", always_true.test(&42));
    println!("  test(&-1): {}", always_true.test(&-1));
    println!("  test(&0): {}", always_true.test(&0));
    println!("  name: {:?}", always_true.name());

    // BoxPredicate::always_false
    let always_false: BoxPredicate<i32> = BoxPredicate::always_false();
    println!("\nBoxPredicate::always_false():");
    println!("  test(&42): {}", always_false.test(&42));
    println!("  test(&-1): {}", always_false.test(&-1));
    println!("  test(&0): {}", always_false.test(&0));
    println!("  name: {:?}", always_false.name());

    println!("\n=== RcPredicate always_true/always_false Demo ===\n");

    // RcPredicate::always_true
    let rc_always_true: RcPredicate<String> = RcPredicate::always_true();
    println!("RcPredicate::always_true():");
    println!(
        "  test(&\"hello\"): {}",
        rc_always_true.test(&"hello".to_string())
    );
    println!(
        "  test(&\"world\"): {}",
        rc_always_true.test(&"world".to_string())
    );
    println!("  name: {:?}", rc_always_true.name());

    // RcPredicate::always_false
    let rc_always_false: RcPredicate<String> = RcPredicate::always_false();
    println!("\nRcPredicate::always_false():");
    println!(
        "  test(&\"hello\"): {}",
        rc_always_false.test(&"hello".to_string())
    );
    println!(
        "  test(&\"world\"): {}",
        rc_always_false.test(&"world".to_string())
    );
    println!("  name: {:?}", rc_always_false.name());

    // Can be cloned and reused
    let rc_clone = rc_always_true.clone();
    println!("\nAfter cloning, still usable:");
    println!(
        "  Original: test(&\"test\"): {}",
        rc_always_true.test(&"test".to_string())
    );
    println!(
        "  Clone: test(&\"test\"): {}",
        rc_clone.test(&"test".to_string())
    );

    println!("\n=== ArcPredicate always_true/always_false Demo ===\n");

    // ArcPredicate::always_true
    let arc_always_true: ArcPredicate<i32> = ArcPredicate::always_true();
    println!("ArcPredicate::always_true():");
    println!("  test(&100): {}", arc_always_true.test(&100));
    println!("  test(&-100): {}", arc_always_true.test(&-100));
    println!("  name: {:?}", arc_always_true.name());

    // ArcPredicate::always_false
    let arc_always_false: ArcPredicate<i32> = ArcPredicate::always_false();
    println!("\nArcPredicate::always_false():");
    println!("  test(&100): {}", arc_always_false.test(&100));
    println!("  test(&-100): {}", arc_always_false.test(&-100));
    println!("  name: {:?}", arc_always_false.name());

    println!("\n=== Combining with other predicates ===\n");

    // Combining with always_true (AND)
    let is_positive = BoxPredicate::new(|x: &i32| *x > 0);
    let combined_and_true = is_positive.and(BoxPredicate::always_true());
    println!("is_positive AND always_true:");
    println!(
        "  test(&5): {} (equivalent to is_positive)",
        combined_and_true.test(&5)
    );
    println!(
        "  test(&-3): {} (equivalent to is_positive)",
        combined_and_true.test(&-3)
    );

    // Combining with always_false (AND)
    let is_positive = BoxPredicate::new(|x: &i32| *x > 0);
    let combined_and_false = is_positive.and(BoxPredicate::always_false());
    println!("\nis_positive AND always_false:");
    println!("  test(&5): {} (always false)", combined_and_false.test(&5));
    println!(
        "  test(&-3): {} (always false)",
        combined_and_false.test(&-3)
    );

    // Combining with always_true (OR)
    let is_positive = BoxPredicate::new(|x: &i32| *x > 0);
    let combined_or_true = is_positive.or(BoxPredicate::always_true());
    println!("\nis_positive OR always_true:");
    println!("  test(&5): {} (always true)", combined_or_true.test(&5));
    println!("  test(&-3): {} (always true)", combined_or_true.test(&-3));

    // Combining with always_false (OR)
    let is_positive = BoxPredicate::new(|x: &i32| *x > 0);
    let combined_or_false = is_positive.or(BoxPredicate::always_false());
    println!("\nis_positive OR always_false:");
    println!(
        "  test(&5): {} (equivalent to is_positive)",
        combined_or_false.test(&5)
    );
    println!(
        "  test(&-3): {} (equivalent to is_positive)",
        combined_or_false.test(&-3)
    );

    println!("\n=== Practical scenarios: Default pass/reject filters ===\n");

    // Scenario 1: Default pass-all filter
    let numbers = vec![1, 2, 3, 4, 5];
    let pass_all = BoxPredicate::<i32>::always_true();
    let filtered: Vec<_> = numbers.iter().copied().filter(pass_all.into_fn()).collect();
    println!("Default pass all elements: {:?} -> {:?}", numbers, filtered);

    // Scenario 2: Default reject-all filter
    let numbers = vec![1, 2, 3, 4, 5];
    let reject_all = BoxPredicate::<i32>::always_false();
    let filtered: Vec<_> = numbers
        .iter()
        .copied()
        .filter(reject_all.into_fn())
        .collect();
    println!(
        "Default reject all elements: {:?} -> {:?}",
        numbers, filtered
    );

    // Scenario 3: Configurable filter
    fn configurable_filter(enable_filter: bool) -> BoxPredicate<i32> {
        if enable_filter {
            BoxPredicate::new(|x: &i32| *x > 3)
        } else {
            BoxPredicate::always_true()
        }
    }

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

    let filter_enabled = configurable_filter(true);
    let filtered: Vec<_> = numbers
        .iter()
        .copied()
        .filter(filter_enabled.into_fn())
        .collect();
    println!("\nFilter enabled: {:?} -> {:?}", numbers, filtered);

    let filter_disabled = configurable_filter(false);
    let filtered: Vec<_> = numbers
        .iter()
        .copied()
        .filter(filter_disabled.into_fn())
        .collect();
    println!("Filter disabled: {:?} -> {:?}", numbers, filtered);
}

pub fn always_false() -> Self

Creates a predicate that always returns false.

Returns

A new RcPredicate that always returns false.

Examples

use prism3_function::predicate::{Predicate, RcPredicate};

let pred: RcPredicate<i32> = RcPredicate::always_false();
assert!(!pred.test(&42));
assert!(!pred.test(&-1));
assert!(!pred.test(&0));

Examples found in repository

examples/always_predicate_demo.rs (line 46)

fn main() {
    println!("=== BoxPredicate always_true/always_false Demo ===\n");

    // BoxPredicate::always_true
    let always_true: BoxPredicate<i32> = BoxPredicate::always_true();
    println!("BoxPredicate::always_true():");
    println!("  test(&42): {}", always_true.test(&42));
    println!("  test(&-1): {}", always_true.test(&-1));
    println!("  test(&0): {}", always_true.test(&0));
    println!("  name: {:?}", always_true.name());

    // BoxPredicate::always_false
    let always_false: BoxPredicate<i32> = BoxPredicate::always_false();
    println!("\nBoxPredicate::always_false():");
    println!("  test(&42): {}", always_false.test(&42));
    println!("  test(&-1): {}", always_false.test(&-1));
    println!("  test(&0): {}", always_false.test(&0));
    println!("  name: {:?}", always_false.name());

    println!("\n=== RcPredicate always_true/always_false Demo ===\n");

    // RcPredicate::always_true
    let rc_always_true: RcPredicate<String> = RcPredicate::always_true();
    println!("RcPredicate::always_true():");
    println!(
        "  test(&\"hello\"): {}",
        rc_always_true.test(&"hello".to_string())
    );
    println!(
        "  test(&\"world\"): {}",
        rc_always_true.test(&"world".to_string())
    );
    println!("  name: {:?}", rc_always_true.name());

    // RcPredicate::always_false
    let rc_always_false: RcPredicate<String> = RcPredicate::always_false();
    println!("\nRcPredicate::always_false():");
    println!(
        "  test(&\"hello\"): {}",
        rc_always_false.test(&"hello".to_string())
    );
    println!(
        "  test(&\"world\"): {}",
        rc_always_false.test(&"world".to_string())
    );
    println!("  name: {:?}", rc_always_false.name());

    // Can be cloned and reused
    let rc_clone = rc_always_true.clone();
    println!("\nAfter cloning, still usable:");
    println!(
        "  Original: test(&\"test\"): {}",
        rc_always_true.test(&"test".to_string())
    );
    println!(
        "  Clone: test(&\"test\"): {}",
        rc_clone.test(&"test".to_string())
    );

    println!("\n=== ArcPredicate always_true/always_false Demo ===\n");

    // ArcPredicate::always_true
    let arc_always_true: ArcPredicate<i32> = ArcPredicate::always_true();
    println!("ArcPredicate::always_true():");
    println!("  test(&100): {}", arc_always_true.test(&100));
    println!("  test(&-100): {}", arc_always_true.test(&-100));
    println!("  name: {:?}", arc_always_true.name());

    // ArcPredicate::always_false
    let arc_always_false: ArcPredicate<i32> = ArcPredicate::always_false();
    println!("\nArcPredicate::always_false():");
    println!("  test(&100): {}", arc_always_false.test(&100));
    println!("  test(&-100): {}", arc_always_false.test(&-100));
    println!("  name: {:?}", arc_always_false.name());

    println!("\n=== Combining with other predicates ===\n");

    // Combining with always_true (AND)
    let is_positive = BoxPredicate::new(|x: &i32| *x > 0);
    let combined_and_true = is_positive.and(BoxPredicate::always_true());
    println!("is_positive AND always_true:");
    println!(
        "  test(&5): {} (equivalent to is_positive)",
        combined_and_true.test(&5)
    );
    println!(
        "  test(&-3): {} (equivalent to is_positive)",
        combined_and_true.test(&-3)
    );

    // Combining with always_false (AND)
    let is_positive = BoxPredicate::new(|x: &i32| *x > 0);
    let combined_and_false = is_positive.and(BoxPredicate::always_false());
    println!("\nis_positive AND always_false:");
    println!("  test(&5): {} (always false)", combined_and_false.test(&5));
    println!(
        "  test(&-3): {} (always false)",
        combined_and_false.test(&-3)
    );

    // Combining with always_true (OR)
    let is_positive = BoxPredicate::new(|x: &i32| *x > 0);
    let combined_or_true = is_positive.or(BoxPredicate::always_true());
    println!("\nis_positive OR always_true:");
    println!("  test(&5): {} (always true)", combined_or_true.test(&5));
    println!("  test(&-3): {} (always true)", combined_or_true.test(&-3));

    // Combining with always_false (OR)
    let is_positive = BoxPredicate::new(|x: &i32| *x > 0);
    let combined_or_false = is_positive.or(BoxPredicate::always_false());
    println!("\nis_positive OR always_false:");
    println!(
        "  test(&5): {} (equivalent to is_positive)",
        combined_or_false.test(&5)
    );
    println!(
        "  test(&-3): {} (equivalent to is_positive)",
        combined_or_false.test(&-3)
    );

    println!("\n=== Practical scenarios: Default pass/reject filters ===\n");

    // Scenario 1: Default pass-all filter
    let numbers = vec![1, 2, 3, 4, 5];
    let pass_all = BoxPredicate::<i32>::always_true();
    let filtered: Vec<_> = numbers.iter().copied().filter(pass_all.into_fn()).collect();
    println!("Default pass all elements: {:?} -> {:?}", numbers, filtered);

    // Scenario 2: Default reject-all filter
    let numbers = vec![1, 2, 3, 4, 5];
    let reject_all = BoxPredicate::<i32>::always_false();
    let filtered: Vec<_> = numbers
        .iter()
        .copied()
        .filter(reject_all.into_fn())
        .collect();
    println!(
        "Default reject all elements: {:?} -> {:?}",
        numbers, filtered
    );

    // Scenario 3: Configurable filter
    fn configurable_filter(enable_filter: bool) -> BoxPredicate<i32> {
        if enable_filter {
            BoxPredicate::new(|x: &i32| *x > 3)
        } else {
            BoxPredicate::always_true()
        }
    }

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

    let filter_enabled = configurable_filter(true);
    let filtered: Vec<_> = numbers
        .iter()
        .copied()
        .filter(filter_enabled.into_fn())
        .collect();
    println!("\nFilter enabled: {:?} -> {:?}", numbers, filtered);

    let filter_disabled = configurable_filter(false);
    let filtered: Vec<_> = numbers
        .iter()
        .copied()
        .filter(filter_disabled.into_fn())
        .collect();
    println!("Filter disabled: {:?} -> {:?}", numbers, filtered);
}

pub fn name(&self) -> Option<&str>

Returns the name of this predicate, if set.

Returns

An Option containing the predicate’s name.

Examples found in repository

examples/predicate_set_name_demo.rs (line 56)

fn demo_rc_predicate() {
    println!("2. RcPredicate Naming Functionality");

    // Using new_with_name
    let pred1 = RcPredicate::new_with_name("greater_than_10", |x: &i32| *x > 10);
    println!("   Using new_with_name:");
    println!("     Name: {:?}", pred1.name());
    println!("     Test 15: {}", pred1.test(&15));

    // Using set_name
    let mut pred2 = RcPredicate::new(|x: &i32| *x < 100);
    println!("\n   Using set_name:");
    println!("     Initial name: {:?}", pred2.name());
    pred2.set_name("less_than_100");
    println!("     Name after setting: {:?}", pred2.name());
    println!("     Test 50: {}", pred2.test(&50));

    // Name is preserved after cloning
    let pred3 = pred2.clone();
    println!("\n   Name preserved after cloning:");
    println!("     Cloned name: {:?}", pred3.name());
    println!("     Test 80: {}\n", pred3.test(&80));
}

examples/predicate_demo.rs (line 169)

fn logical_composition_examples() {
    println!("--- 5. Logical Composition Examples ---");

    let positive = RcPredicate::new_with_name("positive", |x: &i32| *x > 0);
    let even = RcPredicate::new_with_name("even", |x: &i32| x % 2 == 0);
    let less_than_ten = RcPredicate::new_with_name("less_than_ten", |x: &i32| *x < 10);

    // AND composition
    let positive_and_even = positive.and(even.clone());
    println!("positive AND even: name={:?}", positive_and_even.name());
    println!("  Test 4: {}", positive_and_even.test(&4));
    println!("  Test 5: {}", positive_and_even.test(&5));

    // OR composition
    let positive_or_even = positive.or(even.clone());
    println!("positive OR even: name={:?}", positive_or_even.name());
    println!("  Test -2: {}", positive_or_even.test(&-2));
    println!("  Test 5: {}", positive_or_even.test(&5));

    // NOT composition
    let not_positive = positive.not();
    println!("NOT positive: name={:?}", not_positive.name());
    println!("  Test 5: {}", not_positive.test(&5));
    println!("  Test -3: {}", not_positive.test(&-3));

    // NAND composition
    let nand = positive.nand(even.clone());
    println!("positive NAND even: name={:?}", nand.name());
    println!("  Test 3: {}", nand.test(&3)); // true NAND false = true
    println!("  Test 4: {}", nand.test(&4)); // true NAND true = false

    // XOR composition
    let xor = positive.xor(even.clone());
    println!("positive XOR even: name={:?}", xor.name());
    println!("  Test 3: {}", xor.test(&3)); // true XOR false = true
    println!("  Test 4: {}", xor.test(&4)); // true XOR true = false
    println!("  Test -2: {}", xor.test(&-2)); // false XOR true = true

    // NOR composition
    let nor = positive.nor(even.clone());
    println!("positive NOR even: name={:?}", nor.name());
    println!("  Test -3: {}", nor.test(&-3)); // false NOR false = true
    println!("  Test 3: {}", nor.test(&3)); // true NOR false = false
    println!("  Test -2: {}", nor.test(&-2)); // false NOR true = false
    println!("  Test 4: {}", nor.test(&4)); // true NOR true = false

    // Complex composition
    let complex = positive.and(even.clone()).and(less_than_ten.clone());
    println!("Complex composition: name={:?}", complex.name());
    println!("  Test 4: {}", complex.test(&4));
    println!("  Test 12: {}", complex.test(&12));
}

examples/always_predicate_demo.rs (line 43)

fn main() {
    println!("=== BoxPredicate always_true/always_false Demo ===\n");

    // BoxPredicate::always_true
    let always_true: BoxPredicate<i32> = BoxPredicate::always_true();
    println!("BoxPredicate::always_true():");
    println!("  test(&42): {}", always_true.test(&42));
    println!("  test(&-1): {}", always_true.test(&-1));
    println!("  test(&0): {}", always_true.test(&0));
    println!("  name: {:?}", always_true.name());

    // BoxPredicate::always_false
    let always_false: BoxPredicate<i32> = BoxPredicate::always_false();
    println!("\nBoxPredicate::always_false():");
    println!("  test(&42): {}", always_false.test(&42));
    println!("  test(&-1): {}", always_false.test(&-1));
    println!("  test(&0): {}", always_false.test(&0));
    println!("  name: {:?}", always_false.name());

    println!("\n=== RcPredicate always_true/always_false Demo ===\n");

    // RcPredicate::always_true
    let rc_always_true: RcPredicate<String> = RcPredicate::always_true();
    println!("RcPredicate::always_true():");
    println!(
        "  test(&\"hello\"): {}",
        rc_always_true.test(&"hello".to_string())
    );
    println!(
        "  test(&\"world\"): {}",
        rc_always_true.test(&"world".to_string())
    );
    println!("  name: {:?}", rc_always_true.name());

    // RcPredicate::always_false
    let rc_always_false: RcPredicate<String> = RcPredicate::always_false();
    println!("\nRcPredicate::always_false():");
    println!(
        "  test(&\"hello\"): {}",
        rc_always_false.test(&"hello".to_string())
    );
    println!(
        "  test(&\"world\"): {}",
        rc_always_false.test(&"world".to_string())
    );
    println!("  name: {:?}", rc_always_false.name());

    // Can be cloned and reused
    let rc_clone = rc_always_true.clone();
    println!("\nAfter cloning, still usable:");
    println!(
        "  Original: test(&\"test\"): {}",
        rc_always_true.test(&"test".to_string())
    );
    println!(
        "  Clone: test(&\"test\"): {}",
        rc_clone.test(&"test".to_string())
    );

    println!("\n=== ArcPredicate always_true/always_false Demo ===\n");

    // ArcPredicate::always_true
    let arc_always_true: ArcPredicate<i32> = ArcPredicate::always_true();
    println!("ArcPredicate::always_true():");
    println!("  test(&100): {}", arc_always_true.test(&100));
    println!("  test(&-100): {}", arc_always_true.test(&-100));
    println!("  name: {:?}", arc_always_true.name());

    // ArcPredicate::always_false
    let arc_always_false: ArcPredicate<i32> = ArcPredicate::always_false();
    println!("\nArcPredicate::always_false():");
    println!("  test(&100): {}", arc_always_false.test(&100));
    println!("  test(&-100): {}", arc_always_false.test(&-100));
    println!("  name: {:?}", arc_always_false.name());

    println!("\n=== Combining with other predicates ===\n");

    // Combining with always_true (AND)
    let is_positive = BoxPredicate::new(|x: &i32| *x > 0);
    let combined_and_true = is_positive.and(BoxPredicate::always_true());
    println!("is_positive AND always_true:");
    println!(
        "  test(&5): {} (equivalent to is_positive)",
        combined_and_true.test(&5)
    );
    println!(
        "  test(&-3): {} (equivalent to is_positive)",
        combined_and_true.test(&-3)
    );

    // Combining with always_false (AND)
    let is_positive = BoxPredicate::new(|x: &i32| *x > 0);
    let combined_and_false = is_positive.and(BoxPredicate::always_false());
    println!("\nis_positive AND always_false:");
    println!("  test(&5): {} (always false)", combined_and_false.test(&5));
    println!(
        "  test(&-3): {} (always false)",
        combined_and_false.test(&-3)
    );

    // Combining with always_true (OR)
    let is_positive = BoxPredicate::new(|x: &i32| *x > 0);
    let combined_or_true = is_positive.or(BoxPredicate::always_true());
    println!("\nis_positive OR always_true:");
    println!("  test(&5): {} (always true)", combined_or_true.test(&5));
    println!("  test(&-3): {} (always true)", combined_or_true.test(&-3));

    // Combining with always_false (OR)
    let is_positive = BoxPredicate::new(|x: &i32| *x > 0);
    let combined_or_false = is_positive.or(BoxPredicate::always_false());
    println!("\nis_positive OR always_false:");
    println!(
        "  test(&5): {} (equivalent to is_positive)",
        combined_or_false.test(&5)
    );
    println!(
        "  test(&-3): {} (equivalent to is_positive)",
        combined_or_false.test(&-3)
    );

    println!("\n=== Practical scenarios: Default pass/reject filters ===\n");

    // Scenario 1: Default pass-all filter
    let numbers = vec![1, 2, 3, 4, 5];
    let pass_all = BoxPredicate::<i32>::always_true();
    let filtered: Vec<_> = numbers.iter().copied().filter(pass_all.into_fn()).collect();
    println!("Default pass all elements: {:?} -> {:?}", numbers, filtered);

    // Scenario 2: Default reject-all filter
    let numbers = vec![1, 2, 3, 4, 5];
    let reject_all = BoxPredicate::<i32>::always_false();
    let filtered: Vec<_> = numbers
        .iter()
        .copied()
        .filter(reject_all.into_fn())
        .collect();
    println!(
        "Default reject all elements: {:?} -> {:?}",
        numbers, filtered
    );

    // Scenario 3: Configurable filter
    fn configurable_filter(enable_filter: bool) -> BoxPredicate<i32> {
        if enable_filter {
            BoxPredicate::new(|x: &i32| *x > 3)
        } else {
            BoxPredicate::always_true()
        }
    }

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

    let filter_enabled = configurable_filter(true);
    let filtered: Vec<_> = numbers
        .iter()
        .copied()
        .filter(filter_enabled.into_fn())
        .collect();
    println!("\nFilter enabled: {:?} -> {:?}", numbers, filtered);

    let filter_disabled = configurable_filter(false);
    let filtered: Vec<_> = numbers
        .iter()
        .copied()
        .filter(filter_disabled.into_fn())
        .collect();
    println!("Filter disabled: {:?} -> {:?}", numbers, filtered);
}

pub fn set_name(&mut self, name: &str)

Sets the name of this predicate.

Parameters

• name - The new name for this predicate.

Examples found in repository

examples/predicate_set_name_demo.rs (line 63)

fn demo_rc_predicate() {
    println!("2. RcPredicate Naming Functionality");

    // Using new_with_name
    let pred1 = RcPredicate::new_with_name("greater_than_10", |x: &i32| *x > 10);
    println!("   Using new_with_name:");
    println!("     Name: {:?}", pred1.name());
    println!("     Test 15: {}", pred1.test(&15));

    // Using set_name
    let mut pred2 = RcPredicate::new(|x: &i32| *x < 100);
    println!("\n   Using set_name:");
    println!("     Initial name: {:?}", pred2.name());
    pred2.set_name("less_than_100");
    println!("     Name after setting: {:?}", pred2.name());
    println!("     Test 50: {}", pred2.test(&50));

    // Name is preserved after cloning
    let pred3 = pred2.clone();
    println!("\n   Name preserved after cloning:");
    println!("     Cloned name: {:?}", pred3.name());
    println!("     Test 80: {}\n", pred3.test(&80));
}

pub fn and<P>(&self, other: P) -> RcPredicate<T>

where P: Predicate<T> + 'static,

Returns a predicate that represents the logical AND of this predicate and another.

Parameters

• other - The other predicate to combine with. Note: This parameter is passed by value and will transfer ownership. If you need to preserve the original predicate, clone it first (if it implements Clone). Can be:
  • A closure: |x: &T| -> bool
  • A function pointer: fn(&T) -> bool
  • A BoxPredicate<T>
  • Another RcPredicate<T> (will be moved)
  • An ArcPredicate<T>
  • Any type implementing Predicate<T>

Returns

A new RcPredicate representing the logical AND.

Examples

Combining with closures (original predicate remains usable)

use prism3_function::predicate::{Predicate, RcPredicate};

let is_positive = RcPredicate::new(|x: &i32| *x > 0);
let is_even = |x: &i32| x % 2 == 0;

// Note: is_positive is borrowed (&self), so it remains usable
let combined = is_positive.and(is_even);
assert!(combined.test(&4));
assert!(!combined.test(&3));

// original predicate remains usable because RcPredicate uses &self
assert!(is_positive.test(&5));

Combining with other RcPredicate (requires clone)

use prism3_function::predicate::{Predicate, RcPredicate};

let is_positive = RcPredicate::new(|x: &i32| *x > 0);
let is_even = RcPredicate::new(|x: &i32| x % 2 == 0);

// Note: is_even parameter is passed by value and will be moved
// If you need to continue using is_even, you should clone it
let combined = is_positive.and(is_even.clone());
assert!(combined.test(&4));

// both original predicates remain usable
assert!(is_positive.test(&5));
assert!(is_even.test(&6));

Reusing the same predicate multiple times

use prism3_function::predicate::{Predicate, RcPredicate};

let is_positive = RcPredicate::new(|x: &i32| *x > 0);

// Note: is_positive is borrowed (&self), so it can be reused
let positive_and_even = is_positive.and(|x: &i32| x % 2 == 0);
let positive_and_small = is_positive.and(|x: &i32| *x < 100);

// is_positive can be combined multiple times because RcPredicate uses &self
assert!(positive_and_even.test(&4));
assert!(positive_and_small.test(&5));
assert!(is_positive.test(&10));

Examples found in repository

examples/predicate_demo.rs (line 107)

fn rc_predicate_examples() {
    println!("--- 3. RcPredicate Examples (Single-threaded Reuse) ---");

    let is_positive = RcPredicate::new(|x: &i32| *x > 0);
    let is_even = RcPredicate::new(|x: &i32| x % 2 == 0);

    // Multiple compositions without consuming the original
    let positive_and_even = is_positive.and(is_even.clone());
    let positive_or_even = is_positive.or(is_even.clone());

    println!("Original predicates still available:");
    println!("  is_positive.test(&5) = {}", is_positive.test(&5));
    println!("  is_even.test(&4) = {}", is_even.test(&4));

    println!("Combined predicates:");
    println!(
        "  positive_and_even.test(&4) = {}",
        positive_and_even.test(&4)
    );
    println!(
        "  positive_or_even.test(&5) = {}",
        positive_or_even.test(&5)
    );

    // Cloning
    let cloned = is_positive.clone();
    println!("Cloned predicate: {}", cloned.test(&10));
}

/// ArcPredicate examples - multi-threaded scenarios
fn arc_predicate_examples() {
    println!("--- 4. ArcPredicate Examples (Multi-threaded Scenarios) ---");

    let is_positive = ArcPredicate::new(|x: &i32| *x > 0);
    let is_even = ArcPredicate::new(|x: &i32| x % 2 == 0);

    // Create combined predicate
    let combined = is_positive.and(is_even);

    // Use in multiple threads
    let handles: Vec<_> = (0..3)
        .map(|i| {
            let pred = combined.clone();
            std::thread::spawn(move || {
                let value = i * 2;
                println!("  Thread {} testing {}: {}", i, value, pred.test(&value));
            })
        })
        .collect();

    for handle in handles {
        handle.join().unwrap();
    }

    // Original predicates still usable
    println!("Original predicates still available in main thread:");
    println!("  is_positive.test(&5) = {}", is_positive.test(&5));
}

/// Logical composition examples
fn logical_composition_examples() {
    println!("--- 5. Logical Composition Examples ---");

    let positive = RcPredicate::new_with_name("positive", |x: &i32| *x > 0);
    let even = RcPredicate::new_with_name("even", |x: &i32| x % 2 == 0);
    let less_than_ten = RcPredicate::new_with_name("less_than_ten", |x: &i32| *x < 10);

    // AND composition
    let positive_and_even = positive.and(even.clone());
    println!("positive AND even: name={:?}", positive_and_even.name());
    println!("  Test 4: {}", positive_and_even.test(&4));
    println!("  Test 5: {}", positive_and_even.test(&5));

    // OR composition
    let positive_or_even = positive.or(even.clone());
    println!("positive OR even: name={:?}", positive_or_even.name());
    println!("  Test -2: {}", positive_or_even.test(&-2));
    println!("  Test 5: {}", positive_or_even.test(&5));

    // NOT composition
    let not_positive = positive.not();
    println!("NOT positive: name={:?}", not_positive.name());
    println!("  Test 5: {}", not_positive.test(&5));
    println!("  Test -3: {}", not_positive.test(&-3));

    // NAND composition
    let nand = positive.nand(even.clone());
    println!("positive NAND even: name={:?}", nand.name());
    println!("  Test 3: {}", nand.test(&3)); // true NAND false = true
    println!("  Test 4: {}", nand.test(&4)); // true NAND true = false

    // XOR composition
    let xor = positive.xor(even.clone());
    println!("positive XOR even: name={:?}", xor.name());
    println!("  Test 3: {}", xor.test(&3)); // true XOR false = true
    println!("  Test 4: {}", xor.test(&4)); // true XOR true = false
    println!("  Test -2: {}", xor.test(&-2)); // false XOR true = true

    // NOR composition
    let nor = positive.nor(even.clone());
    println!("positive NOR even: name={:?}", nor.name());
    println!("  Test -3: {}", nor.test(&-3)); // false NOR false = true
    println!("  Test 3: {}", nor.test(&3)); // true NOR false = false
    println!("  Test -2: {}", nor.test(&-2)); // false NOR true = false
    println!("  Test 4: {}", nor.test(&4)); // true NOR true = false

    // Complex composition
    let complex = positive.and(even.clone()).and(less_than_ten.clone());
    println!("Complex composition: name={:?}", complex.name());
    println!("  Test 4: {}", complex.test(&4));
    println!("  Test 12: {}", complex.test(&12));
}

/// Interior mutability examples
fn interior_mutability_examples() {
    println!("--- 6. Interior Mutability Examples ---");

    // BoxPredicate with counter (RefCell)
    println!("BoxPredicate with counter:");
    let count = RefCell::new(0);
    let pred = BoxPredicate::new(move |x: &i32| {
        *count.borrow_mut() += 1;
        *x > 0
    });
    println!("  Test 5: {}", pred.test(&5));
    println!("  Test -3: {}", pred.test(&-3));
    println!("  Test 10: {}", pred.test(&10));
    // Note: count is moved into the closure, so we can't access it here

    // RcPredicate with cache (RefCell + HashMap)
    println!("\nRcPredicate with cache:");
    let cache: RefCell<HashMap<i32, bool>> = RefCell::new(HashMap::new());
    let expensive_pred = RcPredicate::new(move |x: &i32| {
        let mut c = cache.borrow_mut();
        *c.entry(*x).or_insert_with(|| {
            println!("    Computing result for {} (expensive operation)", x);
            *x > 0 && x % 2 == 0
        })
    });

    println!("  First test 4:");
    println!("    Result: {}", expensive_pred.test(&4));
    println!("  Test 4 again (using cache):");
    println!("    Result: {}", expensive_pred.test(&4));
    println!("  Test 3:");
    println!("    Result: {}", expensive_pred.test(&3));

    // ArcPredicate with thread-safe counter (Mutex)
    println!("\nArcPredicate with thread-safe counter:");
    let counter = Arc::new(Mutex::new(0));
    let pred = ArcPredicate::new({
        let counter = Arc::clone(&counter);
        move |x: &i32| {
            let mut c = counter.lock().unwrap();
            *c += 1;
            *x > 0
        }
    });

    let pred_clone = pred.clone();
    let counter_clone = Arc::clone(&counter);

    let handle = std::thread::spawn(move || {
        pred_clone.test(&5);
        pred_clone.test(&10);
    });

    pred.test(&3);
    handle.join().unwrap();

    println!("  Total call count: {}", counter_clone.lock().unwrap());
}

/// Practical use cases
fn practical_use_cases() {
    println!("--- 7. Practical Use Cases ---");

    // Validation rules
    println!("Scenario 1: Form Validation");
    struct User {
        name: String,
        age: i32,
        email: String,
    }

    let name_valid =
        RcPredicate::new_with_name("name_not_empty", |user: &User| !user.name.is_empty());

    let age_valid = RcPredicate::new_with_name("age_between_18_120", |user: &User| {
        user.age >= 18 && user.age <= 120
    });

    let email_valid =
        RcPredicate::new_with_name("email_contains_at", |user: &User| user.email.contains('@'));

    let all_valid = name_valid.and(age_valid.clone()).and(email_valid.clone());

    let user1 = User {
        name: "Alice".to_string(),
        age: 25,
        email: "alice@example.com".to_string(),
    };

    let user2 = User {
        name: "".to_string(),
        age: 25,
        email: "bob@example.com".to_string(),
    };

    println!("  user1 validation: {}", all_valid.test(&user1));
    println!("  user2 validation: {}", all_valid.test(&user2));

    // Filter pipeline
    println!("\nScenario 2: Data Filtering Pipeline");
    let numbers: Vec<i32> = (-10..=10).collect();

    let positive = |x: &i32| *x > 0;
    let even = |x: &i32| x % 2 == 0;
    let less_than_eight = |x: &i32| *x < 8;

    let filtered: Vec<i32> = numbers
        .iter()
        .filter(|x| positive.test(x))
        .filter(|x| even.test(x))
        .filter(|x| less_than_eight.test(x))
        .copied()
        .collect();

    println!("  Filtered numbers: {:?}", filtered);

    // Strategy pattern
    println!("\nScenario 3: Strategy Pattern");
    let mut strategies: HashMap<&str, RcPredicate<i32>> = HashMap::new();
    strategies.insert("positive", RcPredicate::new(|x: &i32| *x > 0));
    strategies.insert("negative", RcPredicate::new(|x: &i32| *x < 0));
    strategies.insert("even", RcPredicate::new(|x: &i32| x % 2 == 0));

    let test_value = 4;
    for (name, pred) in strategies.iter() {
        println!(
            "  {} strategy test {}: {}",
            name,
            test_value,
            pred.test(&test_value)
        );
    }
}

pub fn or<P>(&self, other: P) -> RcPredicate<T>

where P: Predicate<T> + 'static,

Returns a predicate that represents the logical OR of this predicate and another.

Parameters

• other - The other predicate to combine with. Note: This parameter is passed by value and will transfer ownership. If you need to preserve the original predicate, clone it first (if it implements Clone). Can be:
  • A closure: |x: &T| -> bool
  • A function pointer: fn(&T) -> bool
  • A BoxPredicate<T>
  • Another RcPredicate<T> (will be moved)
  • An ArcPredicate<T>
  • Any type implementing Predicate<T>

Returns

A new RcPredicate representing the logical OR.

Examples

use prism3_function::predicate::{Predicate, RcPredicate};

let is_negative = RcPredicate::new(|x: &i32| *x < 0);
let is_large = |x: &i32| *x > 100;

let combined = is_negative.or(is_large);
assert!(combined.test(&-5));
assert!(combined.test(&150));
assert!(!combined.test(&50));

// original predicate remains usable
assert!(is_negative.test(&-10));

Examples found in repository

examples/predicate_demo.rs (line 108)

fn rc_predicate_examples() {
    println!("--- 3. RcPredicate Examples (Single-threaded Reuse) ---");

    let is_positive = RcPredicate::new(|x: &i32| *x > 0);
    let is_even = RcPredicate::new(|x: &i32| x % 2 == 0);

    // Multiple compositions without consuming the original
    let positive_and_even = is_positive.and(is_even.clone());
    let positive_or_even = is_positive.or(is_even.clone());

    println!("Original predicates still available:");
    println!("  is_positive.test(&5) = {}", is_positive.test(&5));
    println!("  is_even.test(&4) = {}", is_even.test(&4));

    println!("Combined predicates:");
    println!(
        "  positive_and_even.test(&4) = {}",
        positive_and_even.test(&4)
    );
    println!(
        "  positive_or_even.test(&5) = {}",
        positive_or_even.test(&5)
    );

    // Cloning
    let cloned = is_positive.clone();
    println!("Cloned predicate: {}", cloned.test(&10));
}

/// ArcPredicate examples - multi-threaded scenarios
fn arc_predicate_examples() {
    println!("--- 4. ArcPredicate Examples (Multi-threaded Scenarios) ---");

    let is_positive = ArcPredicate::new(|x: &i32| *x > 0);
    let is_even = ArcPredicate::new(|x: &i32| x % 2 == 0);

    // Create combined predicate
    let combined = is_positive.and(is_even);

    // Use in multiple threads
    let handles: Vec<_> = (0..3)
        .map(|i| {
            let pred = combined.clone();
            std::thread::spawn(move || {
                let value = i * 2;
                println!("  Thread {} testing {}: {}", i, value, pred.test(&value));
            })
        })
        .collect();

    for handle in handles {
        handle.join().unwrap();
    }

    // Original predicates still usable
    println!("Original predicates still available in main thread:");
    println!("  is_positive.test(&5) = {}", is_positive.test(&5));
}

/// Logical composition examples
fn logical_composition_examples() {
    println!("--- 5. Logical Composition Examples ---");

    let positive = RcPredicate::new_with_name("positive", |x: &i32| *x > 0);
    let even = RcPredicate::new_with_name("even", |x: &i32| x % 2 == 0);
    let less_than_ten = RcPredicate::new_with_name("less_than_ten", |x: &i32| *x < 10);

    // AND composition
    let positive_and_even = positive.and(even.clone());
    println!("positive AND even: name={:?}", positive_and_even.name());
    println!("  Test 4: {}", positive_and_even.test(&4));
    println!("  Test 5: {}", positive_and_even.test(&5));

    // OR composition
    let positive_or_even = positive.or(even.clone());
    println!("positive OR even: name={:?}", positive_or_even.name());
    println!("  Test -2: {}", positive_or_even.test(&-2));
    println!("  Test 5: {}", positive_or_even.test(&5));

    // NOT composition
    let not_positive = positive.not();
    println!("NOT positive: name={:?}", not_positive.name());
    println!("  Test 5: {}", not_positive.test(&5));
    println!("  Test -3: {}", not_positive.test(&-3));

    // NAND composition
    let nand = positive.nand(even.clone());
    println!("positive NAND even: name={:?}", nand.name());
    println!("  Test 3: {}", nand.test(&3)); // true NAND false = true
    println!("  Test 4: {}", nand.test(&4)); // true NAND true = false

    // XOR composition
    let xor = positive.xor(even.clone());
    println!("positive XOR even: name={:?}", xor.name());
    println!("  Test 3: {}", xor.test(&3)); // true XOR false = true
    println!("  Test 4: {}", xor.test(&4)); // true XOR true = false
    println!("  Test -2: {}", xor.test(&-2)); // false XOR true = true

    // NOR composition
    let nor = positive.nor(even.clone());
    println!("positive NOR even: name={:?}", nor.name());
    println!("  Test -3: {}", nor.test(&-3)); // false NOR false = true
    println!("  Test 3: {}", nor.test(&3)); // true NOR false = false
    println!("  Test -2: {}", nor.test(&-2)); // false NOR true = false
    println!("  Test 4: {}", nor.test(&4)); // true NOR true = false

    // Complex composition
    let complex = positive.and(even.clone()).and(less_than_ten.clone());
    println!("Complex composition: name={:?}", complex.name());
    println!("  Test 4: {}", complex.test(&4));
    println!("  Test 12: {}", complex.test(&12));
}

pub fn not(&self) -> RcPredicate<T>

Returns a predicate that represents the logical negation of this predicate.

Returns

A new RcPredicate representing the logical negation.

Examples found in repository

examples/predicate_demo.rs (line 180)

fn logical_composition_examples() {
    println!("--- 5. Logical Composition Examples ---");

    let positive = RcPredicate::new_with_name("positive", |x: &i32| *x > 0);
    let even = RcPredicate::new_with_name("even", |x: &i32| x % 2 == 0);
    let less_than_ten = RcPredicate::new_with_name("less_than_ten", |x: &i32| *x < 10);

    // AND composition
    let positive_and_even = positive.and(even.clone());
    println!("positive AND even: name={:?}", positive_and_even.name());
    println!("  Test 4: {}", positive_and_even.test(&4));
    println!("  Test 5: {}", positive_and_even.test(&5));

    // OR composition
    let positive_or_even = positive.or(even.clone());
    println!("positive OR even: name={:?}", positive_or_even.name());
    println!("  Test -2: {}", positive_or_even.test(&-2));
    println!("  Test 5: {}", positive_or_even.test(&5));

    // NOT composition
    let not_positive = positive.not();
    println!("NOT positive: name={:?}", not_positive.name());
    println!("  Test 5: {}", not_positive.test(&5));
    println!("  Test -3: {}", not_positive.test(&-3));

    // NAND composition
    let nand = positive.nand(even.clone());
    println!("positive NAND even: name={:?}", nand.name());
    println!("  Test 3: {}", nand.test(&3)); // true NAND false = true
    println!("  Test 4: {}", nand.test(&4)); // true NAND true = false

    // XOR composition
    let xor = positive.xor(even.clone());
    println!("positive XOR even: name={:?}", xor.name());
    println!("  Test 3: {}", xor.test(&3)); // true XOR false = true
    println!("  Test 4: {}", xor.test(&4)); // true XOR true = false
    println!("  Test -2: {}", xor.test(&-2)); // false XOR true = true

    // NOR composition
    let nor = positive.nor(even.clone());
    println!("positive NOR even: name={:?}", nor.name());
    println!("  Test -3: {}", nor.test(&-3)); // false NOR false = true
    println!("  Test 3: {}", nor.test(&3)); // true NOR false = false
    println!("  Test -2: {}", nor.test(&-2)); // false NOR true = false
    println!("  Test 4: {}", nor.test(&4)); // true NOR true = false

    // Complex composition
    let complex = positive.and(even.clone()).and(less_than_ten.clone());
    println!("Complex composition: name={:?}", complex.name());
    println!("  Test 4: {}", complex.test(&4));
    println!("  Test 12: {}", complex.test(&12));
}

pub fn nand<P>(&self, other: P) -> RcPredicate<T>

where P: Predicate<T> + 'static,

Returns a predicate that represents the logical NAND (NOT AND) of this predicate and another.

NAND returns true unless both predicates are true. Equivalent to !(self AND other).

Parameters

• other - The other predicate to combine with. Note: This parameter is passed by value and will transfer ownership. If you need to preserve the original predicate, clone it first (if it implements Clone). Can be:
  • A closure: |x: &T| -> bool
  • A function pointer: fn(&T) -> bool
  • A BoxPredicate<T>
  • Another RcPredicate<T> (will be moved)
  • An ArcPredicate<T>
  • Any type implementing Predicate<T>

Returns

A new RcPredicate representing the logical NAND.

Examples

use prism3_function::predicate::{Predicate, RcPredicate};

let is_positive = RcPredicate::new(|x: &i32| *x > 0);
let is_even = |x: &i32| x % 2 == 0;

let nand = is_positive.nand(is_even);
assert!(nand.test(&3));   // !(true && false) = true
assert!(!nand.test(&4));  // !(true && true) = false

// original predicate remains usable
assert!(is_positive.test(&5));

Examples found in repository

examples/predicate_demo.rs (line 186)

fn logical_composition_examples() {
    println!("--- 5. Logical Composition Examples ---");

    let positive = RcPredicate::new_with_name("positive", |x: &i32| *x > 0);
    let even = RcPredicate::new_with_name("even", |x: &i32| x % 2 == 0);
    let less_than_ten = RcPredicate::new_with_name("less_than_ten", |x: &i32| *x < 10);

    // AND composition
    let positive_and_even = positive.and(even.clone());
    println!("positive AND even: name={:?}", positive_and_even.name());
    println!("  Test 4: {}", positive_and_even.test(&4));
    println!("  Test 5: {}", positive_and_even.test(&5));

    // OR composition
    let positive_or_even = positive.or(even.clone());
    println!("positive OR even: name={:?}", positive_or_even.name());
    println!("  Test -2: {}", positive_or_even.test(&-2));
    println!("  Test 5: {}", positive_or_even.test(&5));

    // NOT composition
    let not_positive = positive.not();
    println!("NOT positive: name={:?}", not_positive.name());
    println!("  Test 5: {}", not_positive.test(&5));
    println!("  Test -3: {}", not_positive.test(&-3));

    // NAND composition
    let nand = positive.nand(even.clone());
    println!("positive NAND even: name={:?}", nand.name());
    println!("  Test 3: {}", nand.test(&3)); // true NAND false = true
    println!("  Test 4: {}", nand.test(&4)); // true NAND true = false

    // XOR composition
    let xor = positive.xor(even.clone());
    println!("positive XOR even: name={:?}", xor.name());
    println!("  Test 3: {}", xor.test(&3)); // true XOR false = true
    println!("  Test 4: {}", xor.test(&4)); // true XOR true = false
    println!("  Test -2: {}", xor.test(&-2)); // false XOR true = true

    // NOR composition
    let nor = positive.nor(even.clone());
    println!("positive NOR even: name={:?}", nor.name());
    println!("  Test -3: {}", nor.test(&-3)); // false NOR false = true
    println!("  Test 3: {}", nor.test(&3)); // true NOR false = false
    println!("  Test -2: {}", nor.test(&-2)); // false NOR true = false
    println!("  Test 4: {}", nor.test(&4)); // true NOR true = false

    // Complex composition
    let complex = positive.and(even.clone()).and(less_than_ten.clone());
    println!("Complex composition: name={:?}", complex.name());
    println!("  Test 4: {}", complex.test(&4));
    println!("  Test 12: {}", complex.test(&12));
}

pub fn xor<P>(&self, other: P) -> RcPredicate<T>

where P: Predicate<T> + 'static,

Returns a predicate that represents the logical XOR (exclusive OR) of this predicate and another.

XOR returns true if exactly one of the predicates is true.

Parameters

• other - The other predicate to combine with. Note: This parameter is passed by value and will transfer ownership. If you need to preserve the original predicate, clone it first (if it implements Clone). Can be:
  • A closure: |x: &T| -> bool
  • A function pointer: fn(&T) -> bool
  • A BoxPredicate<T>
  • Another RcPredicate<T> (will be moved)
  • An ArcPredicate<T>
  • Any type implementing Predicate<T>

Returns

A new RcPredicate representing the logical XOR.

Examples

use prism3_function::predicate::{Predicate, RcPredicate};

let is_positive = RcPredicate::new(|x: &i32| *x > 0);
let is_even = |x: &i32| x % 2 == 0;

let xor = is_positive.xor(is_even);
assert!(xor.test(&3));    // true ^ false = true
assert!(!xor.test(&4));   // true ^ true = false
assert!(!xor.test(&-1));  // false ^ false = false

// original predicate remains usable
assert!(is_positive.test(&5));

Examples found in repository

examples/predicate_demo.rs (line 192)

fn logical_composition_examples() {
    println!("--- 5. Logical Composition Examples ---");

    let positive = RcPredicate::new_with_name("positive", |x: &i32| *x > 0);
    let even = RcPredicate::new_with_name("even", |x: &i32| x % 2 == 0);
    let less_than_ten = RcPredicate::new_with_name("less_than_ten", |x: &i32| *x < 10);

    // AND composition
    let positive_and_even = positive.and(even.clone());
    println!("positive AND even: name={:?}", positive_and_even.name());
    println!("  Test 4: {}", positive_and_even.test(&4));
    println!("  Test 5: {}", positive_and_even.test(&5));

    // OR composition
    let positive_or_even = positive.or(even.clone());
    println!("positive OR even: name={:?}", positive_or_even.name());
    println!("  Test -2: {}", positive_or_even.test(&-2));
    println!("  Test 5: {}", positive_or_even.test(&5));

    // NOT composition
    let not_positive = positive.not();
    println!("NOT positive: name={:?}", not_positive.name());
    println!("  Test 5: {}", not_positive.test(&5));
    println!("  Test -3: {}", not_positive.test(&-3));

    // NAND composition
    let nand = positive.nand(even.clone());
    println!("positive NAND even: name={:?}", nand.name());
    println!("  Test 3: {}", nand.test(&3)); // true NAND false = true
    println!("  Test 4: {}", nand.test(&4)); // true NAND true = false

    // XOR composition
    let xor = positive.xor(even.clone());
    println!("positive XOR even: name={:?}", xor.name());
    println!("  Test 3: {}", xor.test(&3)); // true XOR false = true
    println!("  Test 4: {}", xor.test(&4)); // true XOR true = false
    println!("  Test -2: {}", xor.test(&-2)); // false XOR true = true

    // NOR composition
    let nor = positive.nor(even.clone());
    println!("positive NOR even: name={:?}", nor.name());
    println!("  Test -3: {}", nor.test(&-3)); // false NOR false = true
    println!("  Test 3: {}", nor.test(&3)); // true NOR false = false
    println!("  Test -2: {}", nor.test(&-2)); // false NOR true = false
    println!("  Test 4: {}", nor.test(&4)); // true NOR true = false

    // Complex composition
    let complex = positive.and(even.clone()).and(less_than_ten.clone());
    println!("Complex composition: name={:?}", complex.name());
    println!("  Test 4: {}", complex.test(&4));
    println!("  Test 12: {}", complex.test(&12));
}

pub fn nor<P>(&self, other: P) -> RcPredicate<T>

where P: Predicate<T> + 'static,

Returns a predicate that represents the logical NOR (NOT OR) of this predicate and another.

NOR returns true only when both predicates are false. Equivalent to !(self OR other).

Parameters

• other - The other predicate to combine with. Note: This parameter is passed by value and will transfer ownership. If you need to preserve the original predicate, clone it first (if it implements Clone). Can be:
  • A closure: |x: &T| -> bool
  • A function pointer: fn(&T) -> bool
  • A BoxPredicate<T>
  • Another RcPredicate<T> (will be moved)
  • An ArcPredicate<T>
  • Any type implementing Predicate<T>

Returns

A new RcPredicate representing the logical NOR.

Examples

use prism3_function::predicate::{Predicate, RcPredicate};

let is_positive = RcPredicate::new(|x: &i32| *x > 0);
let is_even = |x: &i32| x % 2 == 0;

let nor = is_positive.nor(is_even);
assert!(nor.test(&-3));   // !(false || false) = true
assert!(!nor.test(&4));   // !(true || true) = false
assert!(!nor.test(&3));   // !(true || false) = false

// Original predicate remains usable
assert!(is_positive.test(&5));

Examples found in repository

examples/predicate_demo.rs (line 199)

fn logical_composition_examples() {
    println!("--- 5. Logical Composition Examples ---");

    let positive = RcPredicate::new_with_name("positive", |x: &i32| *x > 0);
    let even = RcPredicate::new_with_name("even", |x: &i32| x % 2 == 0);
    let less_than_ten = RcPredicate::new_with_name("less_than_ten", |x: &i32| *x < 10);

    // AND composition
    let positive_and_even = positive.and(even.clone());
    println!("positive AND even: name={:?}", positive_and_even.name());
    println!("  Test 4: {}", positive_and_even.test(&4));
    println!("  Test 5: {}", positive_and_even.test(&5));

    // OR composition
    let positive_or_even = positive.or(even.clone());
    println!("positive OR even: name={:?}", positive_or_even.name());
    println!("  Test -2: {}", positive_or_even.test(&-2));
    println!("  Test 5: {}", positive_or_even.test(&5));

    // NOT composition
    let not_positive = positive.not();
    println!("NOT positive: name={:?}", not_positive.name());
    println!("  Test 5: {}", not_positive.test(&5));
    println!("  Test -3: {}", not_positive.test(&-3));

    // NAND composition
    let nand = positive.nand(even.clone());
    println!("positive NAND even: name={:?}", nand.name());
    println!("  Test 3: {}", nand.test(&3)); // true NAND false = true
    println!("  Test 4: {}", nand.test(&4)); // true NAND true = false

    // XOR composition
    let xor = positive.xor(even.clone());
    println!("positive XOR even: name={:?}", xor.name());
    println!("  Test 3: {}", xor.test(&3)); // true XOR false = true
    println!("  Test 4: {}", xor.test(&4)); // true XOR true = false
    println!("  Test -2: {}", xor.test(&-2)); // false XOR true = true

    // NOR composition
    let nor = positive.nor(even.clone());
    println!("positive NOR even: name={:?}", nor.name());
    println!("  Test -3: {}", nor.test(&-3)); // false NOR false = true
    println!("  Test 3: {}", nor.test(&3)); // true NOR false = false
    println!("  Test -2: {}", nor.test(&-2)); // false NOR true = false
    println!("  Test 4: {}", nor.test(&4)); // true NOR true = false

    // Complex composition
    let complex = positive.and(even.clone()).and(less_than_ten.clone());
    println!("Complex composition: name={:?}", complex.name());
    println!("  Test 4: {}", complex.test(&4));
    println!("  Test 12: {}", complex.test(&12));
}

Trait Implementations

impl<T> Clone for RcPredicate<T>

fn clone(&self) -> Self

Clones this predicate.

Creates a new instance that shares the underlying function with the original, allowing multiple references to the same predicate logic.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T> Debug for RcPredicate<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Implements Debug trait for RcPredicate

Shows the predicate name in debug struct format.

impl<T> Display for RcPredicate<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Implements Display trait for RcPredicate

Shows the predicate name if available, or “unnamed” as default.

impl<T: 'static> Predicate<T> for RcPredicate<T>

fn test(&self, value: &T) -> bool

Tests whether the given value satisfies this predicate.

fn into_box(self) -> BoxPredicate<T>

Converts this predicate into a BoxPredicate.

fn into_rc(self) -> RcPredicate<T>

Converts this predicate into an RcPredicate.

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

Converts this predicate into a closure that can be used directly with standard library methods.

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

Converts a reference to this predicate into a BoxPredicate.

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

Converts a reference to this predicate into an RcPredicate.

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

Converts a reference to this predicate into a closure that can be used directly with standard library methods.

fn into_arc(self) -> ArcPredicate<T>

where Self: Sized + Send + Sync + 'static, T: Send + Sync + 'static,

Converts this predicate into an ArcPredicate.

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

where Self: Clone + Sized + Send + Sync + 'static, T: Send + Sync + 'static,

Converts a reference to this predicate into an ArcPredicate.