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!(
103        "Before when - positive: {}, negative: {}",
104        positive, negative
105    );
106    increment_if_positive.apply(&mut positive);
107    increment_if_positive.apply(&mut negative);
108    println!(
109        "After when - positive: {}, negative: {}\n",
110        positive, negative
111    );
112
113    // when().or_else() (conditional branching)
114    let adjust = BoxMutator::new(|x: &mut i32| *x *= 2)
115        .when(|x: &i32| *x > 0)
116        .or_else(|x: &mut i32| *x = -*x);
117
118    let mut positive = 10;
119    let mut negative = -10;
120    println!(
121        "Before when().or_else() - positive: {}, negative: {}",
122        positive, negative
123    );
124    adjust.apply(&mut positive);
125    adjust.apply(&mut negative);
126    println!(
127        "After when().or_else() - positive: {}, negative: {}\n",
128        positive, negative
129    );
130
131    // ========================================================================
132    // Example 6: ArcMutator - Multi-threaded Sharing
133    // ========================================================================
134    println!("Example 6: ArcMutator - Multi-threaded Sharing");
135    println!("{}", "-".repeat(50));
136
137    let shared = ArcMutator::new(|x: &mut i32| *x *= 2);
138
139    // Clone for another thread
140    let shared_clone = shared.clone();
141    let handle = thread::spawn(move || {
142        let mut value = 5;
143        let mutator = shared_clone;
144        mutator.apply(&mut value);
145        println!("In thread: 5 * 2 = {}", value);
146        value
147    });
148
149    // Use in main thread
150    let mut value = 3;
151    let mutator = shared;
152    mutator.apply(&mut value);
153    println!("Main thread: 3 * 2 = {}", value);
154
155    let thread_result = handle.join().unwrap();
156    println!("Thread result: {}\n", thread_result);
157
158    // ========================================================================
159    // Example 7: ArcMutator Composition (without consuming original mutator)
160    // ========================================================================
161    println!("Example 7: ArcMutator Composition (borrowing &self)");
162    println!("{}", "-".repeat(50));
163
164    let double = ArcMutator::new(|x: &mut i32| *x *= 2);
165    let add_ten = ArcMutator::new(|x: &mut i32| *x += 10);
166
167    // Composition doesn't consume the original mutator
168    let pipeline1 = double.and_then(add_ten.clone());
169    let pipeline2 = add_ten.and_then(double.clone());
170
171    let mut value1 = 5;
172    let p1 = pipeline1;
173    p1.apply(&mut value1);
174    println!("pipeline1 (double then add): 5 -> {}", value1);
175
176    let mut value2 = 5;
177    let p2 = pipeline2;
178    p2.apply(&mut value2);
179    println!("pipeline2 (add then double): 5 -> {}", value2);
180
181    // double and add_ten are still available
182    let mut value3 = 10;
183    let d = double;
184    d.apply(&mut value3);
185    println!("Original double still available: 10 -> {}\n", value3);
186
187    // ========================================================================
188    // Example 8: RcMutator - Single-threaded Sharing
189    // ========================================================================
190    println!("Example 8: RcMutator - Single-threaded Sharing");
191    println!("{}", "-".repeat(50));
192
193    let rc_mutator = RcMutator::new(|x: &mut i32| *x *= 2);
194
195    // Clone multiple copies
196    let clone1 = rc_mutator.clone();
197    let clone2 = rc_mutator.clone();
198
199    let mut value1 = 5;
200    let c1 = clone1;
201    c1.apply(&mut value1);
202    println!("clone1: 5 -> {}", value1);
203
204    let mut value2 = 3;
205    let c2 = clone2;
206    c2.apply(&mut value2);
207    println!("clone2: 3 -> {}", value2);
208
209    let mut value3 = 7;
210    let c3 = rc_mutator;
211    c3.apply(&mut value3);
212    println!("Original: 7 -> {}\n", value3);
213
214    // ========================================================================
215    // Example 9: RcMutator Composition (borrowing &self)
216    // ========================================================================
217    println!("Example 9: RcMutator Composition (borrowing &self)");
218    println!("{}", "-".repeat(50));
219
220    let double = RcMutator::new(|x: &mut i32| *x *= 2);
221    let add_ten = RcMutator::new(|x: &mut i32| *x += 10);
222
223    let pipeline1 = double.and_then(add_ten.clone());
224    let pipeline2 = add_ten.and_then(double.clone());
225
226    let mut value1 = 5;
227    let p1 = pipeline1;
228    p1.apply(&mut value1);
229    println!("pipeline1 (double then add): 5 -> {}", value1);
230
231    let mut value2 = 5;
232    let p2 = pipeline2;
233    p2.apply(&mut value2);
234    println!("pipeline2 (add then double): 5 -> {}\n", value2);
235
236    // ========================================================================
237    // Example 10: Unified Mutator trait
238    // ========================================================================
239    println!("Example 10: Unified Mutator trait");
240    println!("{}", "-".repeat(50));
241
242    fn apply_to_all<M: Mutator<i32>>(mutator: &mut M, values: &mut [i32]) {
243        for value in values.iter_mut() {
244            mutator.apply(value);
245        }
246    }
247
248    let mut values1 = vec![1, 2, 3, 4, 5];
249    let mut box_mut = BoxMutator::new(|x: &mut i32| *x *= 2);
250    println!("Using BoxMutator: {:?}", values1);
251    apply_to_all(&mut box_mut, &mut values1);
252    println!("Result: {:?}", values1);
253
254    let mut values2 = vec![1, 2, 3, 4, 5];
255    let mut arc_mut = ArcMutator::new(|x: &mut i32| *x *= 2);
256    println!("Using ArcMutator: {:?}", values2);
257    apply_to_all(&mut arc_mut, &mut values2);
258    println!("Result: {:?}", values2);
259
260    let mut values3 = vec![1, 2, 3, 4, 5];
261    let mut rc_mut = RcMutator::new(|x: &mut i32| *x *= 2);
262    println!("Using RcMutator: {:?}", values3);
263    apply_to_all(&mut rc_mut, &mut values3);
264    println!("Result: {:?}", values3);
265
266    let mut values4 = vec![1, 2, 3, 4, 5];
267    let mut closure = |x: &mut i32| *x *= 2;
268    println!("Using closure: {:?}", values4);
269    apply_to_all(&mut closure, &mut values4);
270    println!("Result: {:?}\n", values4);
271
272    // ========================================================================
273    // Example 11: Complex Data Processing Pipeline
274    // ========================================================================
275    println!("Example 11: Complex Data Processing Pipeline");
276    println!("{}", "-".repeat(50));
277
278    let pipeline = BoxMutator::new(|x: &mut i32| {
279        // Validation: clamp to 0-100
280        *x = (*x).clamp(0, 100);
281    })
282    .and_then(|x: &mut i32| {
283        // Normalization: scale to 0-10
284        *x /= 10;
285    })
286    .and_then(|x: &mut i32| {
287        // Transformation: square
288        *x = *x * *x;
289    });
290
291    let mut value1 = -50;
292    pipeline.apply(&mut value1);
293    println!("-50 -> {}", value1);
294
295    let mut value2 = 200;
296    pipeline.apply(&mut value2);
297    println!("200 -> {}", value2);
298
299    let mut value3 = 30;
300    pipeline.apply(&mut value3);
301    println!("30 -> {}\n", value3);
302
303    // ========================================================================
304    // Example 12: String Processing
305    // ========================================================================
306    println!("Example 12: String Processing");
307    println!("{}", "-".repeat(50));
308
309    let string_processor = BoxMutator::new(|s: &mut String| s.retain(|c| !c.is_whitespace()))
310        .and_then(|s: &mut String| *s = s.to_lowercase())
311        .and_then(|s: &mut String| s.push_str("!!!"));
312
313    let mut text = String::from("Hello World");
314    println!("Original: {}", text);
315    string_processor.apply(&mut text);
316    println!("After processing: {}\n", text);
317
318    // ========================================================================
319    // Example 13: Type Conversion
320    // ========================================================================
321    println!("Example 13: Type Conversion");
322    println!("{}", "-".repeat(50));
323
324    // Closure -> BoxMutator
325    let closure = |x: &mut i32| *x *= 2;
326    let box_mut = closure.into_box();
327    let mut value = 5;
328    box_mut.apply(&mut value);
329    println!("Closure -> BoxMutator: 5 -> {}", value);
330
331    // Closure -> RcMutator
332    let closure = |x: &mut i32| *x *= 2;
333    let rc_mut = closure.into_rc();
334    let mut value = 5;
335    rc_mut.apply(&mut value);
336    println!("Closure -> RcMutator: 5 -> {}", value);
337
338    // Closure -> ArcMutator
339    let closure = |x: &mut i32| *x *= 2;
340    let arc_mut = closure.into_arc();
341    let mut value = 5;
342    arc_mut.apply(&mut value);
343    println!("Closure -> ArcMutator: 5 -> {}", value);
344
345    // BoxMutator -> RcMutator
346    let box_mut = BoxMutator::new(|x: &mut i32| *x *= 2);
347    let rc_mut = box_mut.into_rc();
348    let mut value = 5;
349    rc_mut.apply(&mut value);
350    println!("BoxMutator -> RcMutator: 5 -> {}", value);
351
352    // RcMutator -> BoxMutator
353    let rc_mut = RcMutator::new(|x: &mut i32| *x *= 2);
354    let box_mut = rc_mut.into_box();
355    let mut value = 5;
356    box_mut.apply(&mut value);
357    println!("RcMutator -> BoxMutator: 5 -> {}\n", value);
358
359    // ========================================================================
360    // Example 14: Custom Types
361    // ========================================================================
362    println!("Example 14: Custom Types");
363    println!("{}", "-".repeat(50));
364
365    #[derive(Debug, Clone)]
366    struct Point {
367        x: i32,
368        y: i32,
369    }
370
371    let processor = BoxMutator::new(|p: &mut Point| p.x *= 2)
372        .and_then(|p: &mut Point| p.y *= 2)
373        .and_then(|p: &mut Point| p.x += p.y);
374
375    let mut point = Point { x: 3, y: 4 };
376    println!("Original point: {:?}", point);
377    processor.apply(&mut point);
378    println!("After processing: {:?}\n", point);
379
380    println!("=== All Examples Completed ===");
381}
mutator_demo/mutator_demo.rs

mutator_demo/
mutator_demo.rs
