vendor/version_check-0.1.5/README.md

   1 # version\_check
   2
   3 This tiny crate checks that the running or installed `rustc` meets some version
   4 requirements. The version is queried by calling the Rust compiler with
   5 `--version`. The path to the compiler is determined first via the `RUSTC`
   6 environment variable. If it is not set, then `rustc` is used. If that fails, no
   7 determination is made, and calls return `None`.
   8
   9 ## Usage
  10
  11 Add to your `Cargo.toml` file, typically as a build dependency:
  12
  13 ```toml
  14 [build-dependencies]
  15 version_check = "0.1"
  16 ```
  17
  18 ## Examples
  19
  20 Check that the running compiler is a nightly release:
  21
  22 ```rust
  23 extern crate version_check;
  24
  25 match version_check::is_nightly() {
  26     Some(true) => "running a nightly",
  27     Some(false) => "not nightly",
  28     None => "couldn't figure it out"
  29 };
  30 ```
  31
  32 Check that the running compiler is at least version `1.13.0`:
  33
  34 ```rust
  35 extern crate version_check;
  36
  37 match version_check::is_min_version("1.13.0") {
  38     Some((true, version)) => format!("Yes! It's: {}", version),
  39     Some((false, version)) => format!("No! {} is too old!", version),
  40     None => "couldn't figure it out".into()
  41 };
  42 ```
  43
  44 Check that the running compiler was released on or after `2016-12-18`:
  45
  46 ```rust
  47 extern crate version_check;
  48
  49 match version_check::is_min_date("2016-12-18") {
  50     Some((true, date)) => format!("Yes! It's: {}", date),
  51     Some((false, date)) => format!("No! {} is too long ago!", date),
  52     None => "couldn't figure it out".into()
  53 };
  54 ```
  55
  56 ## Alternatives
  57
  58 This crate is dead simple with no dependencies. If you need something more and
  59 don't care about panicking if the version cannot be obtained or adding
  60 dependencies, see [rustc_version](https://crates.io/crates/rustc_version).
  61
  62 ## License
  63
  64 `version_check` is licensed under either of the following, at your option:
  65
  66  * Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
  67  * MIT License ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)