feat: Improving minigrep using iterators

Author: unpervertedkid

rustlang_book/minigrep/src/lib.rs

@@ -9,13 +9,20 @@ pub struct Config {
 }
 
 impl Config {
-    pub fn build(args: &[String]) -> Result<Config, &'static str> {
-        if args.len() < 3 {
-            return Err("Not enough arguments. ");
-        }
+    pub fn build(mut args: impl Iterator<Item = String>) -> Result<Config, &'static str> {
+        // The first value in the arguments is the name of the program
+        // We dont use this so we get rid of it
+        args.next();
 
-        let query = args[1].clone();
-        let file_path = args[2].clone();
+        let query = match args.next() {
+            Some(arg) => arg,
+            None => return Err("Didn't get a query string"),
+        };
+
+        let file_path = match args.next() {
+            Some(file_path) => file_path,
+            None => return Err("Didn't get a file path"),
+        };
 
         let ignore_case = env::var("IGNORE_CASE").is_ok();
 
@@ -44,28 +51,17 @@ pub fn run(config: Config) -> Result<(), Box<dyn Error>> {
 }
 
 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);
-        }
-    }
-
-    return results;
+    contents
+        .lines()
+        .filter(|line| line.contains(query))
+        .collect()
 }
 
 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);
-        }
-    }
-
-    return results;
+    contents
+        .lines()
+        .filter(|line| line.to_lowercase().contains(query.to_lowercase().as_str()))
+        .collect()
 }
 
 #[cfg(test)]
@@ -75,23 +71,17 @@ mod tests {
     #[test]
     fn case_sensitive() {
         let query = "duct";
-        let contents = "\
-                                Rust:
-                                safe, fast, productive.
-                                Pick three.
-                                Duct tape.";
+
+        let contents = "Rust:\nsafe, fast, productive.\nPick three.\nDuct 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.";
+
+        let contents = "Rust:\nsafe, fast, productive.\nPick three.\nTrust me.";
 
         assert_eq!(
             vec!["Rust:", "Trust me."],

rustlang_book/minigrep/src/main.rs

@@ -2,9 +2,7 @@ use std::{env, process};
 
 use minigrep::Config;
 fn main() {
-    let args: Vec<String> = env::args().collect();
-
-    let config = Config::build(&args).unwrap_or_else(|err| {
+    let config = Config::build(env::args()).unwrap_or_else(|err| {
         eprintln!("Problem parsing arguments: {}", err);
         process::exit(1);
     });