ctl10n (compile time localization) provides you a simple way to embed messages
into binary file without embedding them into source. Internally, ctl10n generates
a simple macro_rules! macro tr!() from the provided a TOML file with strings.
Add ctl10n to your build-dependencies in your Cargo.toml.
If you want to use include_strings you'll need it in dependencies as well.
```toml [package] name = "example" version = "0.1" edition = "2018"
[build-dependencies] ctl10n = "0.1.0"
[dependencies] ctl10n = "0.1.0" ```
Add the following to your build.rs:
```rust
use ctl10n;
fn main() { println!("cargo:rerun-if-changed=build.rs"); println!("cargo:rerun-if-changed=strings.toml"); if let Err(err) = ctl10n::convertdefaultstrings_file() { panic!("{}", err); } } ```
This will generate the file $OUT_DIR/strings.rs from strings.toml.
The TOML file with strings must be a table where all values are strings. Example strings.toml:
toml
message = "Some message"
message-with-args = "Some message with {arg}"
You should include strings.rs somewhere (for example, in lib.rs) to use the generated
macro. You can do this by calling the macro ctl10n::include_strings!() or manually,
using include!().
After including the macro it can be used like this:
```rust
use ctl10n;
ctl10n::include_strings!();
fn main() {
// tr!() with one argument will be translated to string literal
println!(tr!("message"));
println!(tr!("message-with-args"), arg = "foobar");
// tr!() with multiple arguments will be translated to formatted &String
println!("{}", tr!("message-with-args", arg = "foobaz"))
}
```
Output of this code (assuming strings.toml from above):
Some message
Some message with foobar
Some message with foobaz
Trying to use an unknown key or wrong format arguments is a compile-time error.
You can use environment variables to provide a different locale at compile time:
```rust use ctl10n; use std::env;
fn main() { println!("cargo:rerun-if-changed=build.rs"); println!("cargo:rerun-if-changed=locales/*.toml"); if let Err(err) = ctl10n::convertstringsfile( format!( "locales/{}.toml", &env::var("LOCALE").unwrapor("en".tostring()) ), "strings.rs", ) { panic!("{}", err); } } ```
LOCALE=de cargo build