Update the example for Rust

Author: qryxip

examples/rust/Cargo.toml

@@ -7,6 +7,9 @@ version = "0.0.0"
 edition = "2018"
 publish = false
 
+[lib]
+name = "crate" # This crate itself is not intended to be used directly.
+
 [dependencies]
 verification-helper-rust-example-hello = { path = "crates/helloworld/hello" }
 verification-helper-rust-example-input = { path = "crates/io/input" }

examples/rust/src/lib.rs

@@ -1,23 +1,19 @@
 //! Re-exports the crates for rustdoc.
+//!
+//! This crate itself is not intended to be used directly.
+
+// With `custom-build` and `syn` crate, we can expand crate-level rustdocs.
+
+macro_rules! re_export(($($name:ident),* $(,)?) => ($(pub mod $name { pub use ::$name::*; })*));
+
 pub mod helloworld {
     //! Crates of "hello" and "world".
-    pub mod hello {
-        //! A re-export of `verification-helper-rust-example-hello`.
-        pub use hello::*;
-    }
-    pub mod world {
-        //! A re-export of `verification-helper-rust-example-world`.
-        pub use world::*;
-    }
+
+    re_export!(hello, world);
 }
+
 pub mod io {
     //! Crates about IO.
-    pub mod input {
-        //! A re-export of `verification-helper-rust-example-input`.
-        pub use input::*;
-    }
-    pub mod scanner {
-        //! A re-export of `verification-helper-rust-example-scanner`.
-        pub use scanner::*;
-    }
+
+    re_export!(input, scanner);
 }