jabba_lib/
jstring.rs

1//! string
2
3/// Returns the reversed version of the input string.
4///
5/// # Examples
6///
7/// ```
8/// let text = "abcd";
9/// let answer = jabba_lib::jstring::str_rev(text);
10///
11/// assert_eq!(answer, "dcba");
12/// ```
13pub fn str_rev(s: &str) -> String {
14    s.chars().rev().collect::<String>()
15}
16
17/// Returns `true` if the given string is palindrome.
18///
19/// # Examples
20///
21/// ```
22/// let yes = "abcba";
23/// let no = "ABC";
24///
25/// assert_eq!(jabba_lib::jstring::is_palindrome(yes), true);
26/// assert_eq!(jabba_lib::jstring::is_palindrome(no), false);
27/// ```
28pub fn is_palindrome(s: &str) -> bool {
29    s == str_rev(s)
30}
31
32/// Removes the trailing newline of the given string.
33///
34/// It modifies the string in place.
35///
36/// It was inspired by Perl's `chomp()`.
37///
38/// # Examples
39///
40/// ```
41/// let mut hello = String::from("hello\n");
42/// let mut world = String::from("world\r\n");
43///
44/// jabba_lib::jstring::chomp(&mut hello);
45/// jabba_lib::jstring::chomp(&mut world);
46///
47/// assert_eq!(hello, "hello");
48/// assert_eq!(world, "world");
49/// ```
50pub fn chomp(text: &mut String) {
51    if text.ends_with('\n') {
52        text.pop();
53        if text.ends_with('\r') {
54            text.pop();
55        }
56    }
57}
58
59/// Returns a centered string of length `width`.
60///
61/// Padding is done with spaces.
62///
63/// It's similar to Python's `str.center()`.
64///
65/// # Examples
66///
67/// ```
68/// let text = "*";
69/// let result = jabba_lib::jstring::center(text, 3);
70///
71/// assert_eq!(result, " * ");
72/// ```
73pub fn center(s: &str, width: usize) -> String {
74    format!("{s:^w$}", w = width)
75}
76
77/// Returns a capitalized version of the string.
78///
79/// More specifically, it makes the first character upper case and
80/// the rest lower case.
81///
82/// It's like Python's `str.capitalize()`.
83///
84/// # Examples
85///
86/// ```
87/// let name = "kAtE";
88/// let result = jabba_lib::jstring::capitalize(name);
89///
90/// assert_eq!(result, "Kate");
91/// ```
92pub fn capitalize(s: &str) -> String {
93    if s.is_empty() {
94        String::new()
95    } else {
96        let chars: Vec<char> = s.chars().collect();
97        let first = chars[0].to_uppercase();
98        let rest = chars.into_iter().skip(1).collect::<String>().to_lowercase();
99        format!("{}{}", first, rest)
100    }
101}
102
103// ==========================================================================
104
105#[cfg(test)]
106mod tests {
107    use super::*;
108
109    #[test]
110    fn str_rev_test1() {
111        assert_eq!(str_rev(""), "");
112        assert_eq!(str_rev("a"), "a");
113        assert_eq!(str_rev("ab"), "ba");
114        assert_eq!(str_rev("anna"), "anna");
115        assert_eq!(str_rev("abc"), "cba");
116        assert_eq!(str_rev("AbCdE"), "EdCbA");
117    }
118
119    #[test]
120    fn is_palindrome_test1() {
121        assert!(is_palindrome(""));
122        assert!(is_palindrome("a"));
123        assert!(is_palindrome("aa"));
124        assert!(is_palindrome("anna"));
125        assert!(is_palindrome("görög"));
126    }
127
128    #[test]
129    fn is_palindrome_test2() {
130        assert_eq!(is_palindrome("ab"), false);
131        assert_eq!(is_palindrome("Anna"), false);
132    }
133
134    #[test]
135    fn chomp_test1() {
136        let mut text = "".to_string();
137        chomp(&mut text);
138        assert_eq!(text, "");
139        //
140        let mut text = "abc".to_string();
141        chomp(&mut text);
142        assert_eq!(text, "abc");
143        //
144        let mut text = "\n".to_string();
145        chomp(&mut text);
146        assert_eq!(text, "");
147        //
148        let mut text = "\r\n".to_string();
149        chomp(&mut text);
150        assert_eq!(text, "");
151        //
152        let mut text = "\nend".to_string();
153        chomp(&mut text);
154        assert_eq!(text, "\nend");
155        //
156        let mut text = "\r\nend".to_string();
157        chomp(&mut text);
158        assert_eq!(text, "\r\nend");
159        //
160        let mut text = "longer\nstring\n".to_string();
161        chomp(&mut text);
162        assert_eq!(text, "longer\nstring");
163    }
164
165    #[test]
166    fn center_test1() {
167        assert_eq!(center("-", 0), "-");
168        assert_eq!(center("-", 1), "-");
169        assert_eq!(center("-", 2), "- ");
170        assert_eq!(center("-", 3), " - ");
171    }
172
173    #[test]
174    fn capitalize_test1() {
175        assert_eq!(capitalize(""), "");
176        assert_eq!(capitalize("a"), "A");
177        assert_eq!(capitalize("aa"), "Aa");
178        assert_eq!(capitalize("aNnA"), "Anna");
179    }
180}
jabba_lib/jstring.rs

jabba_lib/
jstring.rs
