turns out that one *can* use 'extern crate' in submodules

[rust-101.git] / workspace / src / part12.rs

diff --git a/workspace/src/part12.rs b/workspace/src/part12.rs
index 1d75bfd1ea249d076b3c2428c74ae84b7c9c6c14..4996ac15676dc9b1a399640ad85279a281be12eb 100644 (file)
--- a/workspace/src/part12.rs
+++ b/workspace/src/part12.rs
@@ -1,5 +1,5 @@
-// Rust-101, Part 12: Concurrency (WIP)
-// =================
+// Rust-101, Part 12: Concurrency, Arc, Send
+// =========================================
 
 use std::io::prelude::*;
 use std::{io, fs, thread};
@@ -9,23 +9,22 @@ use std::sync::Arc;
 
 // Before we come to the actual code, we define a data-structure `Options` to store all the information we need
 // to complete the job: Which files to work on, which pattern to look for, and how to output. <br/>
-// Besides just printing all the matching lines, we will also offer to count them, or alternatively to sort them.
 #[derive(Clone,Copy)]
-enum OutputMode {
+pub enum OutputMode {
     Print,
     SortAndPrint,
     Count,
 }
 use self::OutputMode::*;
 
-struct Options {
-    files: Vec<String>,
-    pattern: String,
-    output_mode: OutputMode,
+pub struct Options {
+    pub files: Vec<String>,
+    pub pattern: String,
+    pub output_mode: OutputMode,
 }
 
 
-// The first functions reads the files, and sends every line over the `out_channel`.
+// The first function reads the files, and sends every line over the `out_channel`.
 fn read_files(options: Arc<Options>, out_channel: SyncSender<String>) {
     for file in options.files.iter() {
         // First, we open the file, ignoring any errors.
@@ -43,11 +42,13 @@ fn read_files(options: Arc<Options>, out_channel: SyncSender<String>) {
 
 // The second function filters the lines it receives through `in_channel` with the pattern, and sends
 // matches via `out_channel`.
-fn filter_lines(options: Arc<Options>, in_channel: Receiver<String>, out_channel: SyncSender<String>) {
+fn filter_lines(options: Arc<Options>,
+                in_channel: Receiver<String>,
+                out_channel: SyncSender<String>) {
     // We can simply iterate over the channel, which will stop when the channel is closed.
     for line in in_channel.iter() {
         // `contains` works on lots of types of patterns, but in particular, we can use it to test whether
-        // one string is contained in another.
+        // one string is contained in another. This is another example of Rust using traits as substitute for overloading.
         if line.contains(&options.pattern) {
             unimplemented!()
         }
@@ -70,7 +71,7 @@ fn output_lines(options: Arc<Options>, in_channel: Receiver<String>) {
         },
         SortAndPrint => {
             // We are asked to sort the matching lines before printing. So let's collect them all in a local vector...
-            let data: Vec<String> = in_channel.iter().collect();
+            let mut data: Vec<String> = in_channel.iter().collect();
             // ...and implement the actual sorting later.
             unimplemented!()
         }
@@ -79,11 +80,11 @@ fn output_lines(options: Arc<Options>, in_channel: Receiver<String>) {
 
 // With the operations of the three threads defined, we can now implement a function that performs grepping according
 // to some given options.
-fn run(options: Options) {
+pub fn run(options: Options) {
     // We move the `options` into an `Arc`, as that's what the thread workers expect.
     let options = Arc::new(options);
 
-    // Set up the channels. Use `sync_channel` with buffer-size of 16 to avoid needlessly filling RAM.
+    // This sets up the channels. We use a `sync_channel` with buffer-size of 16 to avoid needlessly filling RAM.
     let (line_sender, line_receiver) = sync_channel(16);
     let (filtered_sender, filtered_receiver) = sync_channel(16);
 
@@ -93,7 +94,9 @@ fn run(options: Options) {
 
     // Same with the filter thread.
     let options2 = options.clone();
-    let handle2 = thread::spawn(move || filter_lines(options2, line_receiver, filtered_sender));
+    let handle2 = thread::spawn(move || {
+        filter_lines(options2, line_receiver, filtered_sender)
+    });
 
     // And the output thread.
     let options3 = options.clone();
@@ -105,17 +108,19 @@ fn run(options: Options) {
     handle3.join().unwrap();
 }
 
-// Now we have all the pieces together for testing our `rgrep` with some hard-coded options.
+// Now we have all the pieces together for testing our rgrep with some hard-coded options.
 pub fn main() {
     let options = Options {
-        files: vec!["src/part10.rs".to_string(), "src/part11.rs".to_string(), "src/part12.rs".to_string()],
+        files: vec!["src/part10.rs".to_string(),
+                    "src/part11.rs".to_string(),
+                    "src/part12.rs".to_string()],
         pattern: "let".to_string(),
         output_mode: Print
     };
     run(options);
 }
 
-// **Exercise 12.1**: Change `rgrep` such that it prints now only the matching lines, but also the name of the file
+// **Exercise 12.1**: Change rgrep such that it prints not only the matching lines, but also the name of the file
 // and the number of the line in the file. You will have to change the type of the channels from `String` to something
 // that records this extra information.