chore: Clean up some formatting in exercises
I noticed some formatting that isn't consistent with the `rustfmt` style and tried my best to run it on the files in the exercises directory (which does fail for files that can't compile!), which just caught some minor whitespace things here and there.
Note: also can't just apply `rustfmt` blindly because of the blank lines that lead to the hint comments
Fixes the irrefutable let pattern warning in `structs1.rs`
PR https://github.com/rust-lang/rustlings/pull/163 accidentally introduced an error using some versions of the Rust compiler where the compiler would (rightly!) complain about an irrefutable let pattern. I have no idea why this did not occur in all versions of the compiler, but here is a way around it.
fix(installation): Fix rustlings installation check
fixes#147
I did some quick testing with the `-x` check:
```sh
if [ -x "$(notrustlings)" ]
then
echo "notrustlings does not exist"
else
echo "notrustlings appears to exist!"
notrustlings
fi
```
which produced:
```
./test.sh: line 12: notrustlings: command not found
notrustlings appears to exist!
./test.sh: line 17: notrustlings: command not found
```
(consistent with comments in issue)
Using `if ! [ -x "$(command -v <command>)" ]` appears to be the standard way to perform this type of check.
chore: Minor text updates
- Make the default rustlings executable text consistent with the README and install script by adding `--force`.
- Remove a missed highlighting character from Issue #133.
Add errors to exercises that compile without user changes
Hi !
I played a bit with rustlings, and I felt that some exercises were incorrect because they passed the tests without me needing to edit the files!
This gave me the feeling that the exercise was skiped! Especially when I use `rustlings watch`, it is easy to miss an exercise because the compilation error that is displayed is the one of the next exercise ...
It is easy to identify "broken" exercises with:
```bash
% find exercises -name "*.rs" | xargs -n 1 rustlings run
...
✅ Successfully ran exercises/move_semantics/move_semantics4.rs
✅ Successfully tested exercises/test2.rs
```
My suggestion is to make sure that these files trigger a compilation error by adding a simple syntax error (e.g. with `???` in the code that must change) so that our Rustacean can then play with it!
Canonicalize paths to fix path matching
This PR should fix#126. The main solution to the issue was using `canonicalize()` on the paths we create for the exercises from `info.toml` and any user-specified paths, so that path `ends_with` matching will work correctly.
As adding calls to the canonicalize function everywhere requires unwrapping, I also decided to extract a struct representing an exercise and use serde to deserialize the paths from the `info.toml` file up front. I also tried to move the path handling out into the `exercise.rs` file and down into `main.rs` so that it doesn't create as much clutter. There was already a lot of unwrapping and path handling in the other files and I felt like it was getting a bit too repetitive.
If the approach is going too far (too many changes etc.) I'm happy to try to produce a smaller PR that fixes the bug without any refactoring.
