One of the first things we see in Rust that we can create a variable with some fixed, hard-coded string. This string will be part of the compiled code of our application and thus we cannot change it at run-time.
examples/embedded-string/src/main.rs
fn main() {
let text = "Hello World!";
println!("{}", text);
}
Sometimes it would be much better if we could store this string in an external file, and then baked into the executable. For example this could be good to allow non-programmers to edit it without any fear of breaking the code. Especially if it is a longer string.
It can be easily solved using he include_str! macro.
It will include the content of a text file relative to the .rs file. In our case we put text.txt in the root
of the project, next to the Cargo.toml file and the included it:
examples/embed-text-file/text.txt
Hello World!
examples/embed-text-file/src/main.rs
fn main() {
let text = include_str!("../text.txt");
println!("{}", text);
}
How to verify
Compile the executable by:
cargo build --release
Because in the example the name of the crate was embed-text-file, this command created a file called target/release/embed-text-file.
I moved it to another folder and ran it from there.
It printed "Hello World!" as expected.
