When teaching I generally remove these. I emphasize that a reference can
generally be used as if you have the referenced value directly, since in
most cases you don't have to explicitly dereference a reference. On the
next slide we show mutable references, and we need to use a deref when
writing through a mutable reference, so I think that's the better place
to point out the deref operator.
Part of #2478 to clean up code blocks when all that is needed is a
trivial debug print statement.
In certain slides (8.1, 9.2, 9.3, 10.5) I've opted to retain the use of
println! because dbg! makes it less readable. The
dbg! macro uses pretty-printing by default and this results in a simple
array such as the one in 8.1 being printed vertically instead of a
cleaner one-liner.
Co-authored-by: Eric Githinji <egithinji@google.com>
The content slides all use `fn main`, with the exception of the testing
segment. But with this change, where it makes sense exercises use tests
instead, and not both tests and `fn main`.
A small change in `book.js` supports running tests when a code sample
does not have `fn main` but does have `#[test]`, so these work
naturally.
Fixes#1581.
The current example demonstrating how rustc prevents dangling references
is really gross and hard to read (my own fault lol, I wrote that
example). I finally realized that there's a much simpler, easier to read
way of expressing the same thing. I also moved this to its own slide
after the reference slides so that we can call it out as an early
example of the borrow checker. I then call back to this example in the
borrow checker slide to remind students that the aliasing rule isn't the
only thing the borrow checker is enforcing.
The example of returning a reference to a local variable doesn't compile
due to a missing lifetime specifier, which isn't what we're trying to
demonstrate with that example. I usually add the lifetime in manually in
order to demonstrate the compiler error, but it occurs to me that if we
make the argument a reference we can sneakily get the correct compiler
error without having to introduce the lifetime syntax.
As discovered during #1961, fixed byte offsets tend to break
translations because the translated strings can end up having a
character on the boundary where we slice.
This PR moves the slides for slices and strings into the day 1 section
on references. This seems like the more natural place to introduce
slices since slices are a type of reference. It then also made sense to
me to follow that with the introduction of `&str` and `String`, since
students now have the context to understand what a "string slice" is. I
also removed the strings slide from the types and values section since
it didn't make sense to cover the same topic twice in the same day. I
tested this new organization in my class on Wednesday and it didn't
cause day 1 to take too long.
A few of the early exercises had much larger estimates than were
actually necessary for the super simple early exercises. I've gone
through and reviewed the time estimates for exercises and tweaked the
estimates based on how much time students have actually needed in my
classes so far.
This is the result of running `dprint fmt` after removing `src/` from
the list of excluded directories.
This also reformats the Rust code: we might want to tweak this a bit in
the future since some of the changes removes the hand-formatting. Of
course, this formatting can be seen as a mis-feature, so maybe this is
good overall.
Thanks to mdbook-i18n-helpers 0.2, the POT file is nearly unchanged
after this, meaning that all existing translations remain valid! A few
messages were changed because of stray whitespace characters:
msgid ""
"Slices always borrow from another object. In this example, `a` has to remain "
-"'alive' (in scope) for at least as long as our slice. "
+"'alive' (in scope) for at least as long as our slice."
msgstr ""
The formatting is enforced in CI and we will have to see how annoying
this is in practice for the many contributors. If it becomes annoying,
we should look into fixing dprint/check#11 so that `dprint` can annotate
the lines that need fixing directly, then I think we can consider more
strict formatting checks.
I added more customization to `rustfmt.toml`. This is to better emulate
the dense style used in the course:
- `max_width = 85` allows lines to take up the full width available in
our code blocks (when taking margins and the line numbers into account).
- `wrap_comments = true` ensures that we don't show very long comments
in the code examples. I edited some comments to shorten them and avoid
unnecessary line breaks — please trim other unnecessarily long comments
when you see them! Remember we're writing code for slides 😄
- `use_small_heuristics = "Max"` allows for things like struct literals
and if-statements to take up the full line width configured above.
The formatting settings apply to all our Rust code right now — I think
we could improve this with https://github.com/dprint/dprint/issues/711
which lets us add per-directory `dprint` configuration files. However,
the `inherit: true` setting is not yet implemented (as far as I can
tell), so a nested configuration file will have to copy most or all of
the top-level file.
I've taken some work by @fw-immunant and others on the new organization
of the course and condensed it into a form amenable to a text editor and
some computational analysis. You can see the inputs in `course.py` but
the interesting bits are the output: `outline.md` and `slides.md`.
The idea is to break the course into more, smaller segments with
exercises at the ends and breaks in between. So `outline.md` lists the
segments, their duration, and sums those durations up per-day. It shows
we're about an hour too long right now! There are more details of the
segments in `slides.md`, or you can see mostly the same stuff in
`course.py`.
This now contains all of the content from the v1 course, ensuring both
that we've covered everything and that we'll have somewhere to redirect
every page.
Fixes#1082.
Fixes#1465.
---------
Co-authored-by: Nicole LeGare <dlegare.1001@gmail.com>
Co-authored-by: Martin Geisler <mgeisler@google.com>
