diff options
Diffstat (limited to 'src/doc/book/listings/ch13-functional-features/listing-13-18/src/lib.rs')
-rw-r--r-- | src/doc/book/listings/ch13-functional-features/listing-13-18/src/lib.rs | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-18/src/lib.rs b/src/doc/book/listings/ch13-functional-features/listing-13-18/src/lib.rs new file mode 100644 index 000000000..292b09789 --- /dev/null +++ b/src/doc/book/listings/ch13-functional-features/listing-13-18/src/lib.rs @@ -0,0 +1,104 @@ +use std::env; +use std::error::Error; +use std::fs; + +pub struct Config { + pub query: String, + pub file_path: String, + pub ignore_case: bool, +} + +impl Config { + pub fn build(args: &[String]) -> Result<Config, &'static str> { + if args.len() < 3 { + return Err("not enough arguments"); + } + + let query = args[1].clone(); + let file_path = args[2].clone(); + + let ignore_case = env::var("IGNORE_CASE").is_ok(); + + Ok(Config { + query, + file_path, + ignore_case, + }) + } +} + +pub fn run(config: Config) -> Result<(), Box<dyn Error>> { + let contents = fs::read_to_string(config.file_path)?; + + let results = if config.ignore_case { + search_case_insensitive(&config.query, &contents) + } else { + search(&config.query, &contents) + }; + + for line in results { + println!("{line}"); + } + + Ok(()) +} + +pub fn search<'a>(query: &str, contents: &'a str) -> Vec<&'a str> { + let mut results = Vec::new(); + + for line in contents.lines() { + if line.contains(query) { + results.push(line); + } + } + + results +} + +pub fn search_case_insensitive<'a>( + query: &str, + contents: &'a str, +) -> Vec<&'a str> { + let query = query.to_lowercase(); + let mut results = Vec::new(); + + for line in contents.lines() { + if line.to_lowercase().contains(&query) { + results.push(line); + } + } + + results +} + +#[cfg(test)] +mod tests { + use super::*; + + #[test] + fn case_sensitive() { + let query = "duct"; + let contents = "\ +Rust: +safe, fast, productive. +Pick three. +Duct tape."; + + assert_eq!(vec!["safe, fast, productive."], search(query, contents)); + } + + #[test] + fn case_insensitive() { + let query = "rUsT"; + let contents = "\ +Rust: +safe, fast, productive. +Pick three. +Trust me."; + + assert_eq!( + vec!["Rust:", "Trust me."], + search_case_insensitive(query, contents) + ); + } +} |