typist_rust/
lib.rs

1//! Simple typing game written in Rust.
2extern crate generic_matrix;
3
4use generic_matrix::Matrix;
5use std::io;
6use std::time::{Duration, Instant};
7
8mod words;
9
10/* Main methods for running the program */
11
12pub fn run(num_rounds: u32, num_words: u32) {
13    let mut mistake_count = 0;
14    let mut char_count = 0;
15    let mut word_count = 0;
16    let mut elapsed_time: Duration = Duration::from_secs(0);
17
18    for _ in 0..num_rounds {
19        let result = play_one_round(num_words);
20        mistake_count += result.mistakes;
21        char_count += result.answer.chars().count();
22        word_count += num_words;
23        elapsed_time += result.time;
24
25        if result.mistakes == 0 {
26            println!("Correct!\n");
27        } else {
28            println!("Number of mistakes: {}\n", result.mistakes);
29        }
30    }
31
32    print_results(mistake_count, char_count, word_count, elapsed_time);
33}
34
35/// Play one round (display a string and have the user type an answer), returning a RoundResult.
36fn play_one_round(num_words: u32) -> RoundResult {
37    let line = generate_string(num_words);
38
39    println!("{}", line);
40    let mut answer = String::new();
41
42    let begin = Instant::now();
43    io::stdin()
44        .read_line(&mut answer)
45        .expect("Failed to read from console.");
46    let end = Instant::now();
47
48    let answer = String::from(answer.trim());
49    let mistakes = edit_distance(line.trim(), &answer);
50
51    RoundResult {
52        answer,
53        mistakes,
54        time: end - begin,
55    }
56}
57
58/// Outcome of a single round.
59struct RoundResult {
60    answer: String,
61    mistakes: u32,
62    time: Duration,
63}
64
65fn print_results(mistake_count: u32, char_count: usize, word_count: u32, elapsed_time: Duration) {
66    // Dodge possible division by zero.
67    if word_count == 0 || elapsed_time.as_secs() == 0 {
68        println!("No data to calculate.");
69        return;
70    }
71
72    let secs = elapsed_time.as_secs() as f64;
73
74    println!(
75        "{:30}{:>.3}\n\
76         {:30}{:>.3}\n",
77        "Mistakes per word:",
78        mistake_count as f64 / word_count as f64,
79        "Characters per second:",
80        char_count as f64 / secs,
81    );
82}
83
84/* String generation and manipulation functions */
85
86fn generate_string(num_words: u32) -> String {
87    (0..num_words)
88        .map(|_| words::get_word())
89        .collect::<Vec<_>>()
90        .join(" ")
91}
92
93/// Calculate the minimum number of edits (add, delete, replace) needed to transform `a` into `b`.
94fn edit_distance(a: &str, b: &str) -> u32 {
95    let a: Vec<char> = a.chars().collect();
96    let b: Vec<char> = b.chars().collect();
97
98    let mut distances = Matrix::from_fn(a.len() + 1, b.len() + 1, |_, _| 0);
99
100    // Push initial conditions into the matrix
101    for j in 1..=b.len() {
102        distances[(0, j)] = j as u32;
103    }
104
105    for i in 1..=a.len() {
106        distances[(i, 0)] = i as u32;
107    }
108
109    use std::cmp::min;
110
111    for i in 1..=a.len() {
112        for j in 1..=b.len() {
113            let compare = if a[i - 1] == b[j - 1] { 0 } else { 1 };
114            let distance = min(
115                distances[(i, j - 1)] + 1,
116                min(
117                    distances[(i - 1, j)] + 1,
118                    distances[(i - 1, j - 1)] + compare,
119                ),
120            );
121            distances[(i, j)] = distance;
122        }
123    }
124
125    distances[(a.len(), b.len())]
126}
127
128#[cfg(test)]
129mod tests {
130    use super::*;
131
132    #[test]
133    fn test_edit_distance_short_cases() {
134        assert_eq!(0, edit_distance("", ""));
135        assert_eq!(0, edit_distance("a", "a"));
136        assert_eq!(1, edit_distance("x", ""));
137        assert_eq!(1, edit_distance("", "q"));
138        assert_eq!(1, edit_distance("p", "q"));
139        assert_eq!(1, edit_distance("ap", "p"));
140        assert_eq!(2, edit_distance("ap", "b"));
141    }
142
143    #[test]
144    fn test_edit_distance_normal_words() {
145        assert_eq!(3, edit_distance("hector", "extort"));
146        assert_eq!(4, edit_distance("abcd", "defg"));
147    }
148
149    #[test]
150    fn test_non_ascii_characters() {
151        assert_eq!(
152            4,
153            edit_distance("Добрый день", "Добрый вечер")
154        );
155    }
156
157    #[test]
158    fn test_edit_distance_big_difference() {
159        assert_eq!(10, edit_distance("", "1234567890"));
160        assert_eq!(10, edit_distance("abc", "1234567890abc"));
161        assert_eq!(10, edit_distance("abc", "abc1234567890"));
162        assert_eq!(13, edit_distance("abc", "abc1234567890abc"));
163
164        assert_eq!(10, edit_distance("1234567890", ""));
165        assert_eq!(10, edit_distance("1234567890abc", "abc"));
166        assert_eq!(10, edit_distance("abc1234567890", "abc"));
167        assert_eq!(13, edit_distance("abc1234567890abc", "abc"));
168    }
169}
typist_rust/lib.rs

typist_rust/
lib.rs
