Macros for including file content

Macros like include_markdown!("README.md", "example") allow you to include incomplete code from markdown code fences. Though Rust doc tests let you hide setup code from being rendered, you cannot do the same when rendering markdown. You can demonstrate just the code you want in markdown while maintaining the benefit of compiling it in tests.

Examples

The include_markdown!() macro resolves a file path relative to the directory containing the crate Cargo.toml manifest file.

Consider a crate README.md with the following content:

The `example()` function returns a model that implements `Debug` so you can easily print it:

```rust example
let m = example()?;
assert_eq!(format!("{m:?}"), r#"Model { name: "example" }"#);
```

We didn't define the example() function nor the type of m. In Rust doc tests you could do so with lines prefaced with # e.g.:

/// ```
/// # #[derive(Debug)] struct Model { name: String }
/// # fn example() -> Result<Model, Box<dyn std::error::Error>> { Ok(Model { name: "example".into() }) }
/// # fn main() -> Result<(), Box<dyn std::error::Error>> {
/// let m = example()?;
/// println!("{m:#?}");
/// # Ok(()) }
/// ```
fn f() {}

All those lines would render in a markdown file. Instead, we could use include_markdown!("README.md", "example") to include the example content from README.md above in a test to make sure it compiles and even runs.

#[derive(Debug)]
struct Model {
    name: String,
}

fn example() -> Result<Model, Box<dyn std::error::Error>> {
    Ok(Model {
        name: "example".into(),
    })
}

#[test]
fn test_example() -> Result<(), Box<dyn std::error::Error>> {
    include_markdown!("README.md", "example");
    Ok(())
}

Macros

include_asciidoc | asciidoc | Includes Rust snippets from AsciiDoc files, commonly with .asciidoc, .adoc, or .asc extensions. include_markdown | | Includes Rust snippets from Markdown files, commonly with .markdown, .mdown, .mkdn, or .md extensions. include_org | org | Includes Rust snippets from Org files, commonly with .org extension. include_textile | textile | Includes Rust snippets from Textile files, commonly with .textile extension.

All of these macros also support the following parameters:

path | (Required) Path relative to the crate root directory. name | (Required) Name of the code fence to include. scope | Include the snippet in braces { .. }. relative | (Requires rustc 1.88 or newer) Path is relative to the source file calling the macro. May show an error in rust-analyzer until rust-lang/rust-analyzer#15950 is fixed.

License

Licensed under the MIT license.