# lib.rs - source
Source of the Rust file `/home/runner/.cargo/registry/src/github.com-1ecc6299db9ec823/paste-0.1.18/src/lib.rs`.
Keywords: rust, rustlang, rust-lang

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    //! [![github]](https://github.com/dtolnay/paste)&ensp;[![crates-io]](https://crates.io/crates/paste)&ensp;[![docs-rs]](https://docs.rs/paste)
    //!
    //! [github]: https://img.shields.io/badge/github-8da0cb?style=for-the-badge&labelColor=555555&logo=github
    //! [crates-io]: https://img.shields.io/badge/crates.io-fc8d62?style=for-the-badge&labelColor=555555&logo=rust
    //! [docs-rs]: https://img.shields.io/badge/docs.rs-66c2a5?style=for-the-badge&labelColor=555555&logoColor=white&logo=data:image/svg+xml;base64,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
    //!
    //! <br>
    //!
    //! The nightly-only [`concat_idents!`] macro in the Rust standard library is
    //! notoriously underpowered in that its concatenated identifiers can only refer to
    //! existing items, they can never be used to define something new.
    //!
    //! [`concat_idents!`]: https://doc.rust-lang.org/std/macro.concat_idents.html
    //!
    //! This crate provides a flexible way to paste together identifiers in a macro,
    //! including using pasted identifiers to define new items.
    //!
    //! This approach works with any stable or nightly Rust compiler 1.30+.
    //!
    //! <br>
    //!
    //! # Pasting identifiers
    //!
    //! There are two entry points, `paste::expr!` for macros in expression position and
    //! `paste::item!` for macros in item position.
    //!
    //! Within either one, identifiers inside `[<`...`>]` are pasted together to form a
    //! single identifier.
    //!
    //! ```
    //! // Macro in item position: at module scope or inside of an impl block.
    //! paste::item! {
    //!     // Defines a const called `QRST`.
    //!     const [<Q R S T>]: &str = "success!";
    //! }
    //!
    //! fn main() {
    //!     // Macro in expression position: inside a function body.
    //!     assert_eq!(
    //!         paste::expr! { [<Q R S T>].len() },
    //!         8,
    //!     );
    //! }
    //! ```
    //!
    //! <br><br>
    //!
    //! # More elaborate examples
    //!
    //! This program demonstrates how you may want to bundle a paste invocation inside
    //! of a more convenient user-facing macro of your own. Here the `routes!(A, B)`
    //! macro expands to a vector containing `ROUTE_A` and `ROUTE_B`.
    //!
    //! ```
    //! const ROUTE_A: &str = "/a";
    //! const ROUTE_B: &str = "/b";
    //!
    //! macro_rules! routes {
    //!     ($($route:ident),*) => {{
    //!         paste::expr! {
    //!             vec![$( [<ROUTE_ $route>] ),*]
    //!         }
    //!     }}
    //! }
    //!
    //! fn main() {
    //!     let routes = routes!(A, B);
    //!     assert_eq!(routes, vec!["/a", "/b"]);
    //! }
    //! ```
    //!
    //! The next example shows a macro that generates accessor methods for some struct
    //! fields.
    //!
    //! ```
    //! macro_rules! make_a_struct_and_getters {
    //!     ($name:ident { $($field:ident),* }) => {
    //!         // Define a struct. This expands to:
    //!         //
    //!         //     pub struct S {
    //!         //         a: String,
    //!         //         b: String,
    //!         //         c: String,
    //!         //     }
    //!         pub struct $name {
    //!             $(
    //!                 $field: String,
    //!             )*
    //!         }
    //!
    //!         // Build an impl block with getters. This expands to:
    //!         //
    //!         //     impl S {
    //!         //         pub fn get_a(&self) -> &str { &self.a }
    //!         //         pub fn get_b(&self) -> &str { &self.b }
    //!         //         pub fn get_c(&self) -> &str { &self.c }
    //!         //     }
    //!         paste::item! {
    //!             impl $name {
    //!                 $(
    //!                     pub fn [<get_ $field>](&self) -> &str {
    //!                         &self.$field
    //!                     }
    //!                 )*
    //!             }
    //!         }
    //!     }
    //! }
    //!
    //! make_a_struct_and_getters!(S { a, b, c });
    //!
    //! fn call_some_getters(s: &S) -> bool {
    //!     s.get_a() == s.get_b() && s.get_c().is_empty()
    //! }
    //! #
    //! # fn main() {}
    //! ```
    //!
    //! <br><br>
    //!
    //! # Case conversion
    //!
    //! Use `$var:lower` or `$var:upper` in the segment list to convert an
    //! interpolated segment to lower- or uppercase as part of the paste. For
    //! example, `[<ld_ $reg:lower _expr>]` would paste to `ld_bc_expr` if invoked
    //! with $reg=`Bc`.
    //!
    //! Use `$var:snake` to convert CamelCase input to snake\_case.
    //! Use `$var:camel` to convert snake\_case to CamelCase.
    //! These compose, so for example `$var:snake:upper` would give you SCREAMING\_CASE.
    //!
    //! The precise Unicode conversions are as defined by [`str::to_lowercase`] and
    //! [`str::to_uppercase`].
    //!
    //! [`str::to_lowercase`]: https://doc.rust-lang.org/std/primitive.str.html#method.to_lowercase
    //! [`str::to_uppercase`]: https://doc.rust-lang.org/std/primitive.str.html#method.to_uppercase

    #![no_std]

    use proc_macro_hack::proc_macro_hack;

    /// Paste identifiers within a macro invocation that expands to an expression.
    #[proc_macro_hack]
    pub use paste_impl::expr;

    /// Paste identifiers within a macro invocation that expands to one or more
    /// items.
    ///
    /// An item is like a struct definition, function, impl block, or anything else
    /// that can appear at the top level of a module scope.
    pub use paste_impl::item;

    /// Paste identifiers within a macro invocation that expands to one or more
    /// macro_rules macros or items containing macros.
    pub use paste_impl::item_with_macros;

    #[doc(hidden)]
    pub use paste_impl::EnumHack;