Another update from ingydotnet^djgoku

Task/Unix-ls/Rust/unix-ls.rust

@@ -1,17 +1,24 @@
-use std::os;
-use std::io::fs;
+use std::{env, fmt, fs, process};
+use std::io::{self, Write};
+use std::path::Path;
 
 fn main() {
-	let cwd = os::getcwd();
-	let info = fs::readdir(&cwd).unwrap();
-
-	let mut filenames = Vec::new();
-	for entry in info.iter() {
-		filenames.push(entry.filename_str().unwrap());
-	}
-
-	filenames.sort();
-	for filename in filenames.iter() {
-		println!("{}", filename);
-	}
+    let cur = env::current_dir().unwrap_or_else(|e| exit_err(e, 1));
+    let arg = env::args().nth(1);
+    print_files(arg.as_ref().map_or(cur.as_path(), |p| Path::new(p)))
+        .unwrap_or_else(|e| exit_err(e, 2));
+}
+
+#[inline]
+fn print_files(path: &Path) -> io::Result<()> {
+    for x in try!(fs::read_dir(path)) {
+        println!("{}", try!(x).file_name().to_string_lossy());
+    }
+    Ok(())
+}
+
+#[inline]
+fn exit_err<T>(msg: T, code: i32) -> ! where T: fmt::Display {
+    writeln!(&mut io::stderr(), "{}", msg).expect("Could not write to stderr");
+    process::exit(code)
 }