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flagon-io/hello

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hello/src/lib.rs

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Greet people from the command line1//! Greetings.
2
Extract argument parsing into parse_args in lib.rs3/// Parsed command-line options.
4#[derive(Debug, Default, PartialEq, Eq)]
5pub struct Options {
6 /// The name to greet, if one was given.
7 pub name: Option<String>,
Add --shout flag that upper-cases the greeting8 /// Whether to upper-case the greeting (`--shout`).
9 pub shout: bool,
Add --version flag that prints the crate version and exits10 /// Whether to print the crate version and exit (`--version`).
11 pub version: bool,
Extract argument parsing into parse_args in lib.rs12}
13
14/// Parses command-line arguments (excluding the program name).
15///
Add --version flag that prints the crate version and exits16/// `--shout` sets [`Options::shout`] and `--version` sets
17/// [`Options::version`]; other arguments starting with `--` are
Add --shout flag that upper-cases the greeting18/// treated as flags and skipped. The name is the first remaining argument.
Extract argument parsing into parse_args in lib.rs19pub fn parse_args<I: IntoIterator<Item = String>>(args: I) -> Options {
Add --shout flag that upper-cases the greeting20 let mut options = Options::default();
21 for arg in args {
22 if arg == "--shout" {
23 options.shout = true;
Add --version flag that prints the crate version and exits24 } else if arg == "--version" {
25 options.version = true;
Add --shout flag that upper-cases the greeting26 } else if !arg.starts_with("--") && options.name.is_none() {
27 options.name = Some(arg);
28 }
29 }
30 options
Extract argument parsing into parse_args in lib.rs31}
32
Add --shout flag that upper-cases the greeting33/// `text` upper-cased.
34pub fn shout(text: &str) -> String {
35 text.to_uppercase()
36}
37
Greet people from the command line38/// The greeting for `name`.
39pub fn greeting(name: &str) -> String {
Handle empty and whitespace-only names, trim whitespace from input40 let trimmed = name.trim();
41 let display_name = if trimmed.is_empty() { "world" } else { trimmed };
42 format!("Hello, {display_name}!")
Greet people from the command line43}
44
Add farewell function alongside greeting45/// The farewell for `name`.
46pub fn farewell(name: &str) -> String {
47 let trimmed = name.trim();
48 let display_name = if trimmed.is_empty() { "world" } else { trimmed };
49 format!("Goodbye, {display_name}!")
50}
51
Greet people from the command line52#[cfg(test)]
53mod tests {
54 use super::*;
55
Extract argument parsing into parse_args in lib.rs56 fn args(list: &[&str]) -> Vec<String> {
57 list.iter().map(|s| s.to_string()).collect()
58 }
59
60 #[test]
61 fn parse_args_no_args() {
62 assert_eq!(parse_args(args(&[])).name, None);
63 }
64
65 #[test]
66 fn parse_args_name() {
67 assert_eq!(parse_args(args(&["Ada"])).name.as_deref(), Some("Ada"));
68 }
69
70 #[test]
71 fn parse_args_skips_leading_flag() {
72 assert_eq!(
73 parse_args(args(&["--unknown", "Ada"])).name.as_deref(),
74 Some("Ada")
75 );
76 }
77
Greet people from the command line78 #[test]
Add --shout flag that upper-cases the greeting79 fn parse_args_shout_defaults_off() {
80 assert!(!parse_args(args(&["Ada"])).shout);
81 }
82
83 #[test]
84 fn parse_args_shout_before_name() {
85 let options = parse_args(args(&["--shout", "Ada"]));
86 assert!(options.shout);
87 assert_eq!(options.name.as_deref(), Some("Ada"));
88 }
89
90 #[test]
91 fn parse_args_shout_after_name() {
92 let options = parse_args(args(&["Ada", "--shout"]));
93 assert!(options.shout);
94 assert_eq!(options.name.as_deref(), Some("Ada"));
95 }
96
97 #[test]
98 fn parse_args_shout_alone() {
99 let options = parse_args(args(&["--shout"]));
100 assert!(options.shout);
101 assert_eq!(options.name, None);
102 }
103
104 #[test]
Add --version flag that prints the crate version and exits105 fn parse_args_version_defaults_off() {
106 assert!(!parse_args(args(&["Ada"])).version);
107 }
108
109 #[test]
110 fn parse_args_version() {
111 let options = parse_args(args(&["--version"]));
112 assert!(options.version);
113 assert_eq!(options.name, None);
114 }
115
116 #[test]
Add --shout flag that upper-cases the greeting117 fn shout_upper_cases_greeting() {
118 assert_eq!(shout(&greeting("Ada")), "HELLO, ADA!");
119 }
120
121 #[test]
Greet people from the command line122 fn greets_by_name() {
123 assert_eq!(greeting("Ada"), "Hello, Ada!");
124 }
Handle empty and whitespace-only names, trim whitespace from input125
126 #[test]
127 fn greets_world_with_empty_string() {
128 assert_eq!(greeting(""), "Hello, world!");
129 }
130
131 #[test]
132 fn greets_world_with_whitespace_only() {
133 assert_eq!(greeting(" "), "Hello, world!");
134 }
135
136 #[test]
137 fn trims_whitespace_from_name() {
138 assert_eq!(greeting(" Ada "), "Hello, Ada!");
139 }
Add farewell function alongside greeting140
141 #[test]
142 fn says_goodbye_by_name() {
143 assert_eq!(farewell("Ada"), "Goodbye, Ada!");
144 }
145
146 #[test]
147 fn says_goodbye_to_world_when_blank() {
148 assert_eq!(farewell(" "), "Goodbye, world!");
149 }
150
151 #[test]
152 fn farewell_trims_whitespace() {
153 assert_eq!(farewell(" Ada "), "Goodbye, Ada!");
154 }
Greet people from the command line155}