v0.1.1: refactor of main

src/main.rs

@@ -3,6 +3,8 @@ extern crate grep;
 use std::env;
 use std::fs::File;
 use std::io::prelude::*;
+use std::process;
+use std::error::Error;
 
 struct Config {
     query: String,
@@ -12,27 +14,46 @@ struct Config {
 fn main() {
     let args: Vec<String> = env::args().collect();
 
-    let conf = parse_config(&args);
+    let conf = Config::new(&args).unwrap_or_else(|err| {
+        println!("Problem parsing arguments: {}", err);
+        process::exit(1);
+    });
+    //let filename = &conf.filename.clone();
 
+    if let Err(e) = run(conf) {
+        println!("Big bad bada boom!\n{:?}", e);
+        //println!("Big bad bada boom!\n{:?}", e.kind());
+        //println!("Big bad bada boom!\n{}", e.description());
+
+        process::exit(1);
+    }
+}
+
+//fn run(conf: Config) -> Result<(), Box<std::io::Error>>
+fn run(conf: Config) -> Result<(), Box<Error>> {
     println!("{:?} {:?}", conf.query, conf.filename);
 
-    let mut f = File::open(&conf.filename).expect(&("file not found: ".to_owned() + &conf.filename));
-    //let mut f = File::open(filename).expect(&format!("file not found: {}", &filename));
+    let mut f = File::open(&conf.filename)?;
 
     let mut contents = String::new();
-    f.read_to_string(&mut contents)
-        .expect("something went wrong reading the file");
+    f.read_to_string(&mut contents)?;
 
     println!("Searching for '{}'", conf.query);
     println!("In file '{}'", conf.filename);
     println!("With text:\n{}", contents);
+
+    Ok(())
 }
 
-//fn parse_config(args: &[String]) -> (&String, &String)
-//fn parse_config(args: &[String]) -> (&str, &str)
-fn parse_config(args: &[String]) -> Config {
-    Config {
+impl Config {
+    fn new(args: &[String]) -> Result<Config, &'static str> {
+        if args.len() < 3 {
+            return Err("too few arguments")
+        }
+
+        Ok(Config {
             query: args[1].clone(),
             filename: args[2].clone(),
+        })
     }
 }