X-Git-Url: https://git.ralfj.de/rust-101.git/blobdiff_plain/188b1ec1b8528e2326791feccc8077e15bd60182..5baae0ea037ed642b7fe8975fb3004b29827d5b1:/src/part14.rs diff --git a/src/part14.rs b/src/part14.rs index 6550fe5..eb2011a 100644 --- a/src/part14.rs +++ b/src/part14.rs @@ -27,7 +27,7 @@ pub fn sort(data: &mut [T]) { /* Invariant: pivot is data[0]; everything with index (0,lpos) is <= pivot; [rpos,len) is >= pivot; lpos < rpos */ loop { - // **Exercise 13.1**: Complete this Quicksort loop. You can use `swap` on slices to swap two elements. Write a + // **Exercise 14.1**: Complete this Quicksort loop. You can use `swap` on slices to swap two elements. Write a // test function for `sort`. unimplemented!() } @@ -47,8 +47,8 @@ pub fn sort(data: &mut [T]) { sort(part2); /*@*/ } -// **Exercise 13.2**: Since `String` implements `PartialEq`, you can now change the function `output_lines` in the previous part -// to call the sort function above. If you did exercise 12.1, you will have slightly more work. Make sure you sort by the matched line +// **Exercise 14.2**: Since `String` implements `PartialEq`, you can now change the function `output_lines` in the previous part +// to call the sort function above. If you did exercise 13.1, you will have slightly more work. Make sure you sort by the matched line // only, not by filename or line number! // Now, we can sort, e.g., an vector of numbers. @@ -82,7 +82,7 @@ fn sort_array() { //@ arguments based on the usage string. External dependencies are declared in the `Cargo.toml` file. //@ I already prepared that file, but the declaration of the dependency is still commented out. So please open `Cargo.toml` of your workspace -//@ now, and enabled the two commented-out lines. Then do `cargo build`. Cargo will now download the crate from crates.io, compile it, +//@ now, and enable the two commented-out lines. Then do `cargo build`. Cargo will now download the crate from crates.io, compile it, //@ and link it to your program. In the future, you can do `cargo update` to make it download new versions of crates you depend on. //@ Note that crates.io is only the default location for dependencies, you can also give it the URL of a git repository or some local //@ path. All of this is explained in the [Cargo Guide](http://doc.crates.io/guide.html). @@ -91,7 +91,8 @@ fn sort_array() { // Remove the attribute of the `rgrep` module to enable compilation. #[cfg(feature = "disabled")] pub mod rgrep { - // Now that `docopt` is linked, we can first add it to the namespace and then import shorter names with `use`. We also import some other pieces that we will need. + // Now that `docopt` is linked, we can first add it to the namespace with `extern crate` and then import shorter names with `use`. + // We also import some other pieces that we will need. extern crate docopt; use self::docopt::Docopt; use part12::{run, Options, OutputMode}; @@ -108,7 +109,7 @@ Options: // This function extracts the rgrep options from the command-line arguments. fn get_options() -> Options { - // Parse `argv` and exit the program with an error message if it fails. This is taken from the [`docopt` documentation](http://burntsushi.net/rustdoc/docopt/). + // This parses `argv` and exit the program with an error message if it fails. The code is taken from the [`docopt` documentation](http://burntsushi.net/rustdoc/docopt/).
//@ The function `and_then` takes a closure from `T` to `Result`, and uses it to transform a `Result` to a //@ `Result`. This way, we can chain computations that only happen if the previous one succeeded (and the error //@ type has to stay the same). In case you know about monads, this style of programming will be familiar to you. @@ -153,7 +154,7 @@ Options: } } -// **Exercise 13.3**: Wouldn't it be nice if rgrep supported regular expressions? There's already a crate that does all the parsing and matching on regular +// **Exercise 14.3**: Wouldn't it be nice if rgrep supported regular expressions? There's already a crate that does all the parsing and matching on regular // expression, it's called [regex](https://crates.io/crates/regex). Add this crate to the dependencies of your workspace, add an option ("-r") to switch // the pattern to regular-expression mode, and change `filter_lines` to honor this option. The documentation of regex is available from its crates.io site. // (You won't be able to use the `regex!` macro if you are on the stable or beta channel of Rust. But it wouldn't help for our use-case anyway.)