eb60fedc9c
The reasons we needed empty `fn main() {}`s were twofold:
- Avoid confusing people when they click the "expand" button on the code
listing and see the auto-main wrapping
- Avoid failing doctests when running `mdbook test` that don't work when
rustdoc wraps a code listing in main
I think I have a solution that mostly solves these cases.
I don't know why this didn't occur to me before. Here's my current
thinking in case these assumptions turn out to be wrong:
There are a [few things that tell mdbook to disable the
main-wrapping][mdbook], and I hadn't noticed one of them until now: if
you annotate a code block with `noplayground`, it won't add a `main`
around it (and it also won't have the "play" button in the upper right
that runs the block and inserts the result into the page).
So instead of putting an empty `fn main() {}` at the bottom of
src/lib.rs files that doesn't make sense, annotate those listings with
`noplayground`. I don't think anyone will miss the play button anyway
because:
- The play button doesn't run tests, so there wasn't any output for
these examples anyway
- If an example doesn't compile, we have it marked `ignore` so that it
doesn't make the tests fail, and `ignore` also disables the play button,
so there isn't a way to see compiler errors either
In most of these cases, `mdbook test` that runs these as doctests will
still wrap these in main, but the tests still pass.
There are some cases, mostly around modules and using `crate::` that
won't pass as doctests when wrapped in main. For those, I've annotated
them with the [undocumented][] [`test_harness`][] attribute that apparently
I was using at some point and then [stopped using][] and now I've
decided to use again, but maybe send in a PR to rust-lang/rust to
change the name to `no_main` and document it or something. In any case,
that shouldn't affect readers at all.
[mdbook]: d0deee90b0/src/renderer/html_handlebars/hbs_renderer.rs (L805-L808)
[undocumented]: https://github.com/rust-lang/rust/issues/42288#issuecomment-309661382
[`test_harness`]: 220352781c/src/librustdoc/doctest.rs (L252)
[stopped using]: https://github.com/rust-lang/book/pull/1233#discussion_r175515585
The Rust Programming Language
This repository contains the source of "The Rust Programming Language" book.
The book is available in dead-tree form from No Starch Press.
You can also read the book for free online. Please see the book as shipped with the latest stable, beta, or nightly Rust releases. Be aware that issues in those versions may have been fixed in this repository already, as those releases are updated less frequently.
See the releases to download just the code of all the code listings that appear in the book.
Requirements
Building the book requires mdBook, ideally the same version that rust-lang/rust uses in this file. To get it:
$ cargo install mdbook --vers [version-num]
Building
To build the book, type:
$ mdbook build
The output will be in the book subdirectory. To check it out, open it in
your web browser.
Firefox:
$ firefox book/index.html # Linux
$ open -a "Firefox" book/index.html # OS X
$ Start-Process "firefox.exe" .\book\index.html # Windows (PowerShell)
$ start firefox.exe .\book\index.html # Windows (Cmd)
Chrome:
$ google-chrome book/index.html # Linux
$ open -a "Google Chrome" book/index.html # OS X
$ Start-Process "chrome.exe" .\book\index.html # Windows (PowerShell)
$ start chrome.exe .\book\index.html # Windows (Cmd)
To run the tests:
$ mdbook test
Contributing
We'd love your help! Please see CONTRIBUTING.md to learn about the kinds of contributions we're looking for.
Translations
We'd love help translating the book! See the Translations label to join in efforts that are currently in progress. Open a new issue to start working on a new language! We're waiting on mdbook support for multiple languages before we merge any in, but feel free to start!
Spellchecking
To scan source files for spelling errors, you can use the spellcheck.sh
script. It needs a dictionary of valid words, which is provided in
dictionary.txt. If the script produces a false positive (say, you used word
BTreeMap which the script considers invalid), you need to add this word to
dictionary.txt (keep the sorted order for consistency).