プログラミングRust メモ (2) cargo
パッケージ作成
cargo new- パッケージを作成する
Create a new cargo package at <path> USAGE: cargo new [OPTIONS] <path> OPTIONS: --registry <REGISTRY> Registry to use --vcs <VCS> Initialize a new repository for the given version control system (git, hg, pijul, or fossil) or do not initialize any version control at all (none), overriding a global configuration. [possible values: git, hg, pijul, fossil, none] --bin Use a binary (application) template [default] --lib Use a library template --edition <YEAR> Edition to set for the crate generated [possible values: 2015, 2018] --name <NAME> Set the resulting package name, defaults to the directory name -v, --verbose Use verbose output (-vv very verbose/build.rs output) -q, --quiet No output printed to stdout --color <WHEN> Coloring: auto, always, never --frozen Require Cargo.lock and cache are up to date --locked Require Cargo.lock is up to date -Z <FLAG>... Unstable (nightly-only) flags to Cargo, see 'cargo -Z help' for details -h, --help Prints help information ARGS: <path>
実行
- 作成したディレクトリ以下で
cargo runを行うと - main binaryを動作させる
Run the main binary of the local package (src/main.rs) USAGE: cargo run [OPTIONS] [--] [args]... OPTIONS: --bin <NAME>... Name of the bin target to run --example <NAME>... Name of the example target to run -p, --package <SPEC> Package with the target to run -j, --jobs <N> Number of parallel jobs, defaults to # of CPUs --release Build artifacts in release mode, with optimizations --features <FEATURES> Space-separated list of features to activate --all-features Activate all available features --no-default-features Do not activate the `default` feature --target <TRIPLE> Build for the target triple --target-dir <DIRECTORY> Directory for all generated artifacts --manifest-path <PATH> Path to Cargo.toml --message-format <FMT> Error format [default: human] [possible values: human, json, short] -v, --verbose Use verbose output (-vv very verbose/build.rs output) -q, --quiet No output printed to stdout --color <WHEN> Coloring: auto, always, never --frozen Require Cargo.lock and cache are up to date --locked Require Cargo.lock is up to date -Z <FLAG>... Unstable (nightly-only) flags to Cargo, see 'cargo -Z help' for details -h, --help Prints help information ARGS: <args>... If neither `--bin` nor `--example` are given, then if the package only has one bin target it will be run. Otherwise `--bin` specifies the bin target to run, and `--example` specifies the example target to run. At most one of `--bin` or `--example` can be provided. All the arguments following the two dashes (`--`) are passed to the binary to run. If you're passing arguments to both Cargo and the binary, the ones after `--` go to the binary, the ones before go to Cargo.
警告
プログラム中で使用しないものをuseに含める
use log::{info,warn}; fn main() { info!("trace"); println!("Hello, world!"); }
実際に動作させると、必要なwarningsが丁寧に出力される 非常にありがたい
warning: unused import: `warn` --> src/main.rs:1:16 | 1 | use log::{info,warn}; | ^^^^ | = note: #[warn(unused_imports)] on by default Finished dev [unoptimized + debuginfo] target(s) in 1.96s Running `target/debug/hello` Hello, world!
- ちなみに、
printlnはmacroのようだ - https://doc.rust-lang.org/std/macro.println.html
- macroは後日書こう
crates.io
rustには標準でcrates.ioというモジュールが登録されているサイトがある。
このサイト非常に便利で、Most Downloadedとか表示されるので人気モジュールとか直ぐに分かる。
実際に各モジュールのページを開くと
例えば、logを開くと、Cargo.tomlに簡単にコピーができるようになってる。
その上で、Usageがきちんと書かれているので
use log::{info, trace, warn}; pub fn shave_the_yak(yak: &mut Yak) { // … }
いきなり訪れた人でも簡単に導入できる。
