pub use part05::BigInt;
-// With our new knowledge on Lifetimes, we are now able to write down the desired type
+// With our new knowledge of lifetimes, we are now able to write down the desired type
// of `min`: We want the function to take two borrows *of the same lifetime*, and then
// return a borrow of that lifetime. If the two input lifetimes would be different, we
// would not know which lifetime to use for the result.
// a pointer in C(++), if you look at what happens during execution - but it's much safer to use.
// For our `vec_min` to be usable with `BigInt`, we need to provide an implementation of
-// `minimum`. You should be able to pretty much copy the code you wrote for exercise 06.1.
+// `Minimum`. You should be able to pretty much copy the code you wrote for exercise 06.1.
impl Minimum for BigInt {
fn min<'a>(&'a self, other: &'a Self) -> &'a Self {
unimplemented!()
// ## Operator Overloading
// How can we know that our `min` function actually does what we want it to do? One possibility
// here is to do *testing*. Rust comes with nice build-in support for both unit tests and integration
-// tests. However, before we go there, we need to have a way of checking whether the results are
+// tests. However, before we go there, we need to have a way of checking whether the results of function calls are
// correct. In other words, we need to define how to test equality of `BigInt`. Being able to
-// test equality is a property of a type, that - you guessed it - Rust expresses as a trait:
-// `PartialEq`. Once a type implements that trait, one can use the `==` operator on it.
+// test equality is a property of a type, that - you guessed it - Rust expresses as a trait: `PartialEq`.
// Doing this for `BigInt` is fairly easy, thanks to our requirement that there be no trailing zeros.
// The `inline` attribute tells Rust that we will typically want this function to be inlined.
// Since implementing `PartialEq` is a fairly mechanical business, you can let Rust automate this
// by adding the attribute `derive(PartialEq)` to the type definition. In case you wonder about
// the "partial", I suggest you check out the documentation of [`PartialEq`](http://doc.rust-lang.org/std/cmp/trait.PartialEq.html)
-// and [`Eq`](http://doc.rust-lang.org/std/cmp/trait.Eq.html). Again, `Eq` can be automatically derived.
+// and [`Eq`](http://doc.rust-lang.org/std/cmp/trait.Eq.html). `Eq` can be automatically derived as well.
-// Now we can compare `BigInt`s! Speaking in C++ terms, we just overloaded the `==` operator
+// Now we can compare `BigInt`s using `==`! Speaking in C++ terms, we just overloaded the `==` operator
// for `BigInt`. Rust does not have function overloading (i.e., it will not dispatch to different
// functions depending on the type of the argument). Instead, one typically finds (or defines) a
// trait that catches the core characteristic common to all the overloads, and writes a single
// function that's generic in the trait. For example, instead of overloading a function for all
-// the ways a string can be represented, one write a generic functions over [ToString](http://doc.rust-lang.org/std/string/trait.ToString.html).
+// the ways a string can be represented, one writes a generic functions over [ToString](http://doc.rust-lang.org/std/string/trait.ToString.html).
// Usually, there is a trait like this that fits the purpose - and if there is, this has the great
// advantage that any type *you* write, that can convert to a string, just has to implement
// that trait to be immediately usable with all the functions out there that generalize over `ToString`.
}
// ## Testing
-// With our equality test written, we are now ready to write out first testcase. It doesn't get much
+// With our equality test written, we are now ready to write our first testcase. It doesn't get much
// simpler: You just write a function (with no arguments or return value), and give it the `test` attribute.
// `assert!` is like `debug_assert!`, but does not get compiled away in a release build.
#[test]
// that users can understand, while `Debug` is meant to show the internal state of data and targeted at
// the programmer. The latter is what we want for `assert_eq!`, so let's get started.
-// Al formating is handled by [`std::fmt`](http://doc.rust-lang.org/std/fmt/index.html). I won't explain
+// All formating is handled by [`std::fmt`](http://doc.rust-lang.org/std/fmt/index.html). I won't explain
// all the details, and refer you to the documentation instead.
use std::fmt;
}
// `Debug` implementations can be automatically generated using the `derive(Debug)` attribute.
-// Now we are ready to use `assert_eq!` to test `vec_min`. While we are at it, let's also follow the usual
-// Rust style of putting tests into a *submodule*, to avoid polluting the namespace. The attribute `cfg(test)`
-// at the submodule means that it will only be compiled when building the tests.
-#[cfg(test)]
-mod tests {
- use super::*;
-
- #[test]
- fn test_vec_min() {
- let b1 = BigInt::new(1);
- let b2 = BigInt::new(42);
- let b3 = BigInt::from_vec(vec![0, 1]);
-
- let v1 = vec![b2.clone(), b1.clone(), b3.clone()];
- let v2 = vec![b2.clone(), b3.clone()];
- assert_eq!(vec_min(&v1), Some(&b1));
- assert_eq!(vec_min(&v2), Some(&b2));
- }
+// Now we are ready to use `assert_eq!` to test `vec_min`.
+#[test]
+fn test_vec_min() {
+ let b1 = BigInt::new(1);
+ let b2 = BigInt::new(42);
+ let b3 = BigInt::from_vec(vec![0, 1]);
+
+ let v1 = vec![b2.clone(), b1.clone(), b3.clone()];
+ let v2 = vec![b2.clone(), b3.clone()];
+ assert_eq!(vec_min(&v1), Some(&b1));
+ assert_eq!(vec_min(&v2), Some(&b2));
}
// **Exercise 07.1**: Add some more testcases. In particular, make sure you test the behavior of
// `vec_min` on an empty vector. Also add tests for `BigInt::from_vec` (in particular, removing
-// trailing zeros) and the functions you wrote for exercise 05.1. Finally, break one of your
-// functions in a subtle way and watch the test fail.
+// trailing zeros). Finally, break one of your functions in a subtle way and watch the test fail.
//
// **Exercise 07.2**: Go back to your good ol' `SomethingOrNothing`, and implement `Display` for it. (This will,
// of course, need a `Display` bound on `T`.) Then you should be able to use them with `println!` just like you do with numbers.
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