simplegrep: touch up

Author: BurntSushi

grep/examples/simplegrep.rs

@@ -3,10 +3,9 @@ extern crate termcolor;
 extern crate walkdir;
 
 use std::env;
+use std::error::Error;
 use std::ffi::OsString;
-use std::path::Path;
 use std::process;
-use std::result;
 
 use grep::cli;
 use grep::printer::{ColorSpecs, StandardBuilder};
@@ -15,52 +14,46 @@ use grep::searcher::{BinaryDetection, SearcherBuilder};
 use termcolor::ColorChoice;
 use walkdir::WalkDir;
 
-macro_rules! fail {
-    ($($tt:tt)*) => {
-        return Err(From::from(format!($($tt)*)));
-    }
-}
-
-type Result<T> = result::Result<T, Box<::std::error::Error>>;
-
 fn main() {
     if let Err(err) = try_main() {
         eprintln!("{}", err);
         process::exit(1);
     }
 }
 
-fn try_main() -> Result<()> {
+fn try_main() -> Result<(), Box<Error>> {
     let mut args: Vec<OsString> = env::args_os().collect();
     if args.len() < 2 {
-        fail!("Usage: simplegrep <pattern> [<path> ...]");
+        return Err("Usage: simplegrep <pattern> [<path> ...]".into());
     }
     if args.len() == 2 {
         args.push(OsString::from("./"));
     }
     search(cli::pattern_from_os(&args[1])?, &args[2..])
 }
 
-fn search(pattern: &str, paths: &[OsString]) -> Result<()> {
+fn search(pattern: &str, paths: &[OsString]) -> Result<(), Box<Error>> {
     let matcher = RegexMatcher::new_line_matcher(&pattern)?;
     let mut searcher = SearcherBuilder::new()
         .binary_detection(BinaryDetection::quit(b'\x00'))
         .line_number(false)
         .build();
     let mut printer = StandardBuilder::new()
         .color_specs(ColorSpecs::default_with_color())
-        .build(cli::stdout(color_choice()));
+        .build(cli::stdout(
+            if cli::is_tty_stdout() {
+                ColorChoice::Auto
+            } else {
+                ColorChoice::Never
+            }
+        ));
 
     for path in paths {
         for result in WalkDir::new(path) {
             let dent = match result {
                 Ok(dent) => dent,
                 Err(err) => {
-                    eprintln!(
-                        "{}: {}",
-                        err.path().unwrap_or(Path::new("error")).display(),
-                        err,
-                    );
+                    eprintln!("{}", err);
                     continue;
                 }
             };
@@ -79,11 +72,3 @@ fn search(pattern: &str, paths: &[OsString]) -> Result<()> {
     }
     Ok(())
 }
-
-fn color_choice() -> ColorChoice {
-    if cli::is_tty_stdout() {
-        ColorChoice::Auto
-    } else {
-        ColorChoice::Never
-    }
-}