Macros for all your token pasting needs
=======================================

[github](https://github.com/as1100k/pastey)
[crates.io](https://crates.io/crates/pastey)
[docs.rs](https://docs.rs/pastey)
[build status](https://github.com/as1100k/pastey/actions?query=branch%master)

**_`pastey` is the fork of `paste` and is aimed to be a drop-in replacement with additional features for
`paste` crate_**

Migrating from paste crate

Migrating from `paste` crate to `pastey` is super simple, just change the following in your `Cargo.toml`

```diff
[dependencies]
- paste = "1"
+ pastey = "*" # Or any specific version of pastey
```

Or even better way:

```diff
[dependencies]
- paste = "1"
+ paste = { package = "pastey", version = "*" }
```


## Quick Start

Add `pastey` as your dependency in `Cargo.toml`

```toml
[dependencies]
# TODO: Replace with latest version available on crates.io
pastey = "*"
```

This approach works with any Rust compiler 1.54+.

## Pasting identifiers

Within the `paste!` macro, identifiers inside `[<`...`>]` are pasted together to
form a single identifier.

```rust
use pastey::paste;

paste! {
    // Defines a const called `QRST`.
    const [<Q R S T>]: &str = "success!";
}

fn main() {
    assert_eq!(
        paste! { [<Q R S T>].len() },
        8,
    );
}
```


## More elaborate example

The next example shows a macro that generates accessor methods for some struct
fields. It demonstrates how you might find it useful to bundle a paste
invocation inside of a macro\_rules macro.

```rust
use pastey::paste;

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! {
            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()
}
```


## Case conversion

The `pastey` crate supports the following case modfiers:

| Modifier                           | Description                           |
|------------------------------------|---------------------------------------|
| `$var:lower`                       | Lower Case                            |
| `$var:upper`                       | Upper Case                            |
| `$var:snake`                       | [Snake Case]                          |
| `$var:camel` or `$var:upper_camel` | Upper Camel Case                      |
| `$var:lower_camel`                 | Lower Camel Case [#4]                 |
| `$var:camel_edge`                  | Covers Edge cases of Camel Case. [#3] |

_**NOTE: The pastey crate is going to be a drop in replacement to paste crate,
and will not change the behaviour of existing modifier like `lower`, `upper`,
`snake` and `camel`. For modifying the behaviour new modifiers will be created,
like `camel_edge`**_

You can also use multiple of these modifers like `$var:snake:upper` would give you
`SCREAMING_SNAKE_CASE`.

Example

```rust
use pastey::paste;

paste! {
    const [<LIB env!("CARGO_PKG_NAME"):snake:upper>]: &str = "libpastey";

    let _ = LIBPASTEY;
}
```

The precise Unicode conversions are as defined by [`str::to_lowercase`] and
[`str::to_uppercase`].

[#3]: https://github.com/AS1100K/pastey/issues/3
[#4]: https://github.com/AS1100K/pastey/issues/4
[`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

## Raw Identifier Generation

`pastey` now supports raw identifiers using a special raw mode. By prefixing a token with `#`
inside the paste syntax, it treats that token as a raw identifier.

```rust
use pastey::paste;

macro_rules! define_struct_and_impl {
    ($name:ident $(- $name_tail:ident)*) => {
        paste!{
            struct [< # $name:camel $( $name_tail)* >]; // '#' signals a raw identifier

            impl [< # $name:camel $( $name_tail)* >] {
                fn [< # $name:snake $( _ $name_tail:snake)* >]() {}
            }

        }
    }
}

define_struct_and_impl!(loop);
define_struct_and_impl!(loop - xyz);

fn test_fn() {
    let _ = Loop::r#loop();
    let _ = Loopxyz::loop_xyz();
}
```


## Pasting documentation strings

Within the `paste!` macro, arguments to a #\[doc ...\] attribute are implicitly
concatenated together to form a coherent documentation string.

```rust
use pastey::paste;

macro_rules! method_new {
    ($ret:ident) => {
        paste! {
            #[doc = "Create a new `" $ret "` object."]
            pub fn new() -> $ret { todo!() }
        }
    };
}

pub struct Pastey {}

method_new!(Pastey);  // expands to #[doc = "Create a new `Paste` object"]
```


#### Credits

This crate is the fork of paste (https://github.com/dtolnay/paste) and I appreciate the efforts of
@dtolnay and other contributors.

#### License

Licensed under either of Apache License, Version
2.0 or MIT license at your option.

Unless you explicitly state otherwise, any contribution intentionally submitted
for inclusion in this crate by you, as defined in the Apache-2.0 license, shall
be dual licensed as above, without any additional terms or conditions.

