mutator_demo/
mutator_demo.rs

1/*******************************************************************************
2 *
3 *    Copyright (c) 2025 - 2026 Haixing Hu.
4 *
5 *    SPDX-License-Identifier: Apache-2.0
6 *
7 *    Licensed under the Apache License, Version 2.0.
8 *
9 ******************************************************************************/
10
11//! Mutator Type Demo
12//!
13//! This example demonstrates the three implementations of Mutator (BoxMutator, ArcMutator, RcMutator)
14//! and their various usage patterns.
15//!
16//! Mutator is used to modify values, unlike the non-mutating Consumer.
17
18use qubit_function::{
19    ArcMutator,
20    BoxMutator,
21    FnMutatorOps,
22    Mutator,
23    RcMutator,
24};
25use std::thread;
26
27fn main() {
28    println!("=== Mutator Demo ===\n");
29
30    // ========================================================================
31    // Example 1: BoxMutator Basic Usage
32    // ========================================================================
33    println!("Example 1: BoxMutator Basic Usage");
34    println!("{}", "-".repeat(50));
35
36    let mutator = BoxMutator::new(|x: &mut i32| {
37        *x *= 2;
38    });
39    let mut value = 5;
40    println!("Initial value: {}", value);
41    mutator.apply(&mut value);
42    println!("After BoxMutator execution: {}\n", value);
43
44    // ========================================================================
45    // Example 2: BoxMutator Method Chaining
46    // ========================================================================
47    println!("Example 2: BoxMutator Method Chaining");
48    println!("{}", "-".repeat(50));
49
50    let chained = BoxMutator::new(|x: &mut i32| {
51        *x *= 2; // multiply by 2
52    })
53    .and_then(|x: &mut i32| {
54        *x += 10; // add 10
55    })
56    .and_then(|x: &mut i32| {
57        *x = *x * *x; // square
58    });
59
60    let mut value = 5;
61    println!("Initial value: {}", value);
62    chained.apply(&mut value);
63    println!("Result: {} (5 * 2 + 10 = 20, 20 * 20 = 400)\n", value);
64
65    // ========================================================================
66    // Example 3: Closure Extension Methods
67    // ========================================================================
68    println!("Example 3: Direct Use of Closure Extension Methods");
69    println!("{}", "-".repeat(50));
70
71    let closure_chain = (|x: &mut i32| *x *= 2).and_then(|x: &mut i32| *x += 10);
72
73    let mut value = 5;
74    println!("Initial value: {}", value);
75    closure_chain.apply(&mut value);
76    println!("Result: {} (5 * 2 + 10 = 20)\n", value);
77
78    // ========================================================================
79    // Example 4: BoxMutator Factory Methods
80    // ========================================================================
81    println!("Example 4: BoxMutator Factory Methods");
82    println!("{}", "-".repeat(50));
83
84    // noop
85    let noop = BoxMutator::<i32>::noop();
86    let mut value = 42;
87    println!("Before noop: {}", value);
88    noop.apply(&mut value);
89    println!("After noop: {} (unchanged)\n", value);
90
91    // ========================================================================
92    // Example 5: Conditional Mutator
93    // ========================================================================
94    println!("Example 5: Conditional Mutator");
95    println!("{}", "-".repeat(50));
96
97    // when (conditional execution)
98    let increment_if_positive = BoxMutator::new(|x: &mut i32| *x += 1).when(|x: &i32| *x > 0);
99
100    let mut positive = 5;
101    let mut negative = -5;
102    println!("Before when - positive: {}, negative: {}", positive, negative);
103    increment_if_positive.apply(&mut positive);
104    increment_if_positive.apply(&mut negative);
105    println!("After when - positive: {}, negative: {}\n", positive, negative);
106
107    // when().or_else() (conditional branching)
108    let adjust = BoxMutator::new(|x: &mut i32| *x *= 2)
109        .when(|x: &i32| *x > 0)
110        .or_else(|x: &mut i32| *x = -*x);
111
112    let mut positive = 10;
113    let mut negative = -10;
114    println!(
115        "Before when().or_else() - positive: {}, negative: {}",
116        positive, negative
117    );
118    adjust.apply(&mut positive);
119    adjust.apply(&mut negative);
120    println!(
121        "After when().or_else() - positive: {}, negative: {}\n",
122        positive, negative
123    );
124
125    // ========================================================================
126    // Example 6: ArcMutator - Multi-threaded Sharing
127    // ========================================================================
128    println!("Example 6: ArcMutator - Multi-threaded Sharing");
129    println!("{}", "-".repeat(50));
130
131    let shared = ArcMutator::new(|x: &mut i32| *x *= 2);
132
133    // Clone for another thread
134    let shared_clone = shared.clone();
135    let handle = thread::spawn(move || {
136        let mut value = 5;
137        let mutator = shared_clone;
138        mutator.apply(&mut value);
139        println!("In thread: 5 * 2 = {}", value);
140        value
141    });
142
143    // Use in main thread
144    let mut value = 3;
145    let mutator = shared;
146    mutator.apply(&mut value);
147    println!("Main thread: 3 * 2 = {}", value);
148
149    let thread_result = handle.join().expect("thread should not panic");
150    println!("Thread result: {}\n", thread_result);
151
152    // ========================================================================
153    // Example 7: ArcMutator Composition (without consuming original mutator)
154    // ========================================================================
155    println!("Example 7: ArcMutator Composition (borrowing &self)");
156    println!("{}", "-".repeat(50));
157
158    let double = ArcMutator::new(|x: &mut i32| *x *= 2);
159    let add_ten = ArcMutator::new(|x: &mut i32| *x += 10);
160
161    // Composition doesn't consume the original mutator
162    let pipeline1 = double.and_then(add_ten.clone());
163    let pipeline2 = add_ten.and_then(double.clone());
164
165    let mut value1 = 5;
166    let p1 = pipeline1;
167    p1.apply(&mut value1);
168    println!("pipeline1 (double then add): 5 -> {}", value1);
169
170    let mut value2 = 5;
171    let p2 = pipeline2;
172    p2.apply(&mut value2);
173    println!("pipeline2 (add then double): 5 -> {}", value2);
174
175    // double and add_ten are still available
176    let mut value3 = 10;
177    let d = double;
178    d.apply(&mut value3);
179    println!("Original double still available: 10 -> {}\n", value3);
180
181    // ========================================================================
182    // Example 8: RcMutator - Single-threaded Sharing
183    // ========================================================================
184    println!("Example 8: RcMutator - Single-threaded Sharing");
185    println!("{}", "-".repeat(50));
186
187    let rc_mutator = RcMutator::new(|x: &mut i32| *x *= 2);
188
189    // Clone multiple copies
190    let clone1 = rc_mutator.clone();
191    let clone2 = rc_mutator.clone();
192
193    let mut value1 = 5;
194    let c1 = clone1;
195    c1.apply(&mut value1);
196    println!("clone1: 5 -> {}", value1);
197
198    let mut value2 = 3;
199    let c2 = clone2;
200    c2.apply(&mut value2);
201    println!("clone2: 3 -> {}", value2);
202
203    let mut value3 = 7;
204    let c3 = rc_mutator;
205    c3.apply(&mut value3);
206    println!("Original: 7 -> {}\n", value3);
207
208    // ========================================================================
209    // Example 9: RcMutator Composition (borrowing &self)
210    // ========================================================================
211    println!("Example 9: RcMutator Composition (borrowing &self)");
212    println!("{}", "-".repeat(50));
213
214    let double = RcMutator::new(|x: &mut i32| *x *= 2);
215    let add_ten = RcMutator::new(|x: &mut i32| *x += 10);
216
217    let pipeline1 = double.and_then(add_ten.clone());
218    let pipeline2 = add_ten.and_then(double.clone());
219
220    let mut value1 = 5;
221    let p1 = pipeline1;
222    p1.apply(&mut value1);
223    println!("pipeline1 (double then add): 5 -> {}", value1);
224
225    let mut value2 = 5;
226    let p2 = pipeline2;
227    p2.apply(&mut value2);
228    println!("pipeline2 (add then double): 5 -> {}\n", value2);
229
230    // ========================================================================
231    // Example 10: Unified Mutator trait
232    // ========================================================================
233    println!("Example 10: Unified Mutator trait");
234    println!("{}", "-".repeat(50));
235
236    fn apply_to_all<M: Mutator<i32>>(mutator: &mut M, values: &mut [i32]) {
237        for value in values.iter_mut() {
238            mutator.apply(value);
239        }
240    }
241
242    let mut values1 = vec![1, 2, 3, 4, 5];
243    let mut box_mut = BoxMutator::new(|x: &mut i32| *x *= 2);
244    println!("Using BoxMutator: {:?}", values1);
245    apply_to_all(&mut box_mut, &mut values1);
246    println!("Result: {:?}", values1);
247
248    let mut values2 = vec![1, 2, 3, 4, 5];
249    let mut arc_mut = ArcMutator::new(|x: &mut i32| *x *= 2);
250    println!("Using ArcMutator: {:?}", values2);
251    apply_to_all(&mut arc_mut, &mut values2);
252    println!("Result: {:?}", values2);
253
254    let mut values3 = vec![1, 2, 3, 4, 5];
255    let mut rc_mut = RcMutator::new(|x: &mut i32| *x *= 2);
256    println!("Using RcMutator: {:?}", values3);
257    apply_to_all(&mut rc_mut, &mut values3);
258    println!("Result: {:?}", values3);
259
260    let mut values4 = vec![1, 2, 3, 4, 5];
261    let mut closure = |x: &mut i32| *x *= 2;
262    println!("Using closure: {:?}", values4);
263    apply_to_all(&mut closure, &mut values4);
264    println!("Result: {:?}\n", values4);
265
266    // ========================================================================
267    // Example 11: Complex Data Processing Pipeline
268    // ========================================================================
269    println!("Example 11: Complex Data Processing Pipeline");
270    println!("{}", "-".repeat(50));
271
272    let pipeline = BoxMutator::new(|x: &mut i32| {
273        // Validation: clamp to 0-100
274        *x = (*x).clamp(0, 100);
275    })
276    .and_then(|x: &mut i32| {
277        // Normalization: scale to 0-10
278        *x /= 10;
279    })
280    .and_then(|x: &mut i32| {
281        // Transformation: square
282        *x = *x * *x;
283    });
284
285    let mut value1 = -50;
286    pipeline.apply(&mut value1);
287    println!("-50 -> {}", value1);
288
289    let mut value2 = 200;
290    pipeline.apply(&mut value2);
291    println!("200 -> {}", value2);
292
293    let mut value3 = 30;
294    pipeline.apply(&mut value3);
295    println!("30 -> {}\n", value3);
296
297    // ========================================================================
298    // Example 12: String Processing
299    // ========================================================================
300    println!("Example 12: String Processing");
301    println!("{}", "-".repeat(50));
302
303    let string_processor = BoxMutator::new(|s: &mut String| s.retain(|c| !c.is_whitespace()))
304        .and_then(|s: &mut String| *s = s.to_lowercase())
305        .and_then(|s: &mut String| s.push_str("!!!"));
306
307    let mut text = String::from("Hello World");
308    println!("Original: {}", text);
309    string_processor.apply(&mut text);
310    println!("After processing: {}\n", text);
311
312    // ========================================================================
313    // Example 13: Type Conversion
314    // ========================================================================
315    println!("Example 13: Type Conversion");
316    println!("{}", "-".repeat(50));
317
318    // Closure -> BoxMutator
319    let closure = |x: &mut i32| *x *= 2;
320    let box_mut = closure.into_box();
321    let mut value = 5;
322    box_mut.apply(&mut value);
323    println!("Closure -> BoxMutator: 5 -> {}", value);
324
325    // Closure -> RcMutator
326    let closure = |x: &mut i32| *x *= 2;
327    let rc_mut = closure.into_rc();
328    let mut value = 5;
329    rc_mut.apply(&mut value);
330    println!("Closure -> RcMutator: 5 -> {}", value);
331
332    // Closure -> ArcMutator
333    let closure = |x: &mut i32| *x *= 2;
334    let arc_mut = closure.into_arc();
335    let mut value = 5;
336    arc_mut.apply(&mut value);
337    println!("Closure -> ArcMutator: 5 -> {}", value);
338
339    // BoxMutator -> RcMutator
340    let box_mut = BoxMutator::new(|x: &mut i32| *x *= 2);
341    let rc_mut = box_mut.into_rc();
342    let mut value = 5;
343    rc_mut.apply(&mut value);
344    println!("BoxMutator -> RcMutator: 5 -> {}", value);
345
346    // RcMutator -> BoxMutator
347    let rc_mut = RcMutator::new(|x: &mut i32| *x *= 2);
348    let box_mut = rc_mut.into_box();
349    let mut value = 5;
350    box_mut.apply(&mut value);
351    println!("RcMutator -> BoxMutator: 5 -> {}\n", value);
352
353    // ========================================================================
354    // Example 14: Custom Types
355    // ========================================================================
356    println!("Example 14: Custom Types");
357    println!("{}", "-".repeat(50));
358
359    #[derive(Debug, Clone)]
360    struct Point {
361        x: i32,
362        y: i32,
363    }
364
365    let processor = BoxMutator::new(|p: &mut Point| p.x *= 2)
366        .and_then(|p: &mut Point| p.y *= 2)
367        .and_then(|p: &mut Point| p.x += p.y);
368
369    let mut point = Point { x: 3, y: 4 };
370    println!("Original point: {:?}", point);
371    processor.apply(&mut point);
372    println!("After processing: {:?}\n", point);
373
374    println!("=== All Examples Completed ===");
375}
mutator_demo/mutator_demo.rs

mutator_demo/
mutator_demo.rs
