src-embed

src-embed is a tiny procedural attribute macro that embeds the original Rust source of an annotated item into the compiled crate as a pub const string. The generated constant is marked #[doc(hidden)] and the original item is re-emitted unchanged so the macro preserves semantics while making the textual source available at compile time or runtime.

Motivation

Sometimes it's useful to keep the literal source of a type, function, trait, or impl block available in the binary for tests, examples, debug output, or documentation tooling. src-embed provides a simple, dependency-light way to make that source accessible.

Features

• Works on struct, enum, fn, trait, and impl items.
• Generates a pub const __<NAME>_SOURCE__: &str containing the source.
• Keeps the original item intact and hidden from the public docs.

Note: the embedded source includes the original attributes and doc comments associated with the annotated item. This ensures /// doc comments (and other outer attributes) appear in the generated string.

Usage

Add the crate as a dependency (path or registry as appropriate) and enable the proc-macro feature in your Cargo.toml if using a local crate.

[dependencies]
src-embed = { path = ".." }

Then annotate an item:

use src_embed::src_embed;

#[src_embed]
pub struct Foo { pub x: u32 }

// You can now refer to `__FOO_SOURCE__` (it is `pub`, but marked
// `#[doc(hidden)]`).

Example

Given:

#[src_embed]
pub fn example() -> &'static str { "hello" }

The macro will emit something like:

#[doc(hidden)]
pub const __EXAMPLE_SOURCE__: &str = "pub fn example() -> &'static str { \"hello\" }";

pub fn example() -> &'static str { "hello" }

Notes

• The constant name is generated from the item's identifier in uppercase and wrapped between __ and _SOURCE__. For certain items (like impls) the macro derives a representative name; when it cannot, it falls back to ITEM or UNKNOWN.

License

This repository is provided under the terms of the included LICENSE file.