minigrep

minigrep/Cargo.toml

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+[package]
+name = "minigrep"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]

minigrep/poems.txt

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+I'm nobody! Who are you?
+Are you nobody, too?
+Then there's a pair of us - don't tell!
+They'd banish us, you know.
+
+How dreary to be somebody!
+How public, like a frog
+To tell your name the livelong day
+To an admiring bog!
+

minigrep/src/lib.rs

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+use std::env;
+use std::error::Error;
+use std::fs;
+
+pub fn run(config: Config) -> Result<(), Box<dyn Error>> {
+    let contents = fs::read_to_string(config.file_path)?;
+
+    let mut results;
+    let casing = (config.ignore_case_arg, config.ignore_case_env);
+
+    // only perform case sensitive search if both
+    // ignore_case_env and ignore_case_arg are false
+    match casing {
+        (false, false) => results = search(&config.query, &contents),
+        (_, _) => results = search_case_insensitive(&config.query, &contents),
+    }
+
+    for line in results {
+        println!("{line}");
+    }
+
+    Ok(())
+}
+
+pub struct Config {
+    pub query: String,
+    pub file_path: String,
+    pub ignore_case_arg: bool,
+    pub ignore_case_env: bool,
+}
+
+impl Config {
+    pub fn build(args: &[String]) -> Result<Config, &'static str> {
+        if args.len() < 4 {
+            return Err("not enough arguments");
+        }
+
+        let query = args[1].clone();
+        let file_path = args[2].clone();
+        let ignore_case_arg = !args[3].clone().is_empty();
+        let ignore_case_env = env::var("IGNORE_CASE").is_ok();
+
+        Ok(Config {
+            query,
+            file_path,
+            ignore_case_arg,
+            ignore_case_env,
+        })
+    }
+}
+
+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 mut results = Vec::new();
+    let query = query.to_lowercase();
+
+    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)
+        );
+    }
+}

minigrep/src/main.rs

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+use minigrep::Config;
+use std::env;
+use std::process;
+
+fn main() {
+    let args: Vec<String> = env::args().collect();
+
+    let config = Config::build(&args).unwrap_or_else(|error| {
+        println!("Problem parsing arguments: {error}");
+        process::exit(1);
+    });
+
+    if let Err(e) = minigrep::run(config) {
+        println!("Application error: {e}");
+        process::exit(1);
+    }
+}
+
+// end of main
+// another way to handle the Config building
+// let config = Config::build(&args);
+// match config {
+//     Err(error) => {
+//         println!("error: {error}");
+//     }
+//     Ok(config) => {
+//         println!(
+//             "searching for \"{}\" in file \"{}\"",
+//             config.query, config.file_path,
+//         );
+//
+//         println!("with text:\n{contents}");
+//     }
+// }