derive_less

A library for generating #[...] and pub code in item declarations.

Example

Suppose you needed the following code:

```rust

[derive(Debug)]

pub struct Foo( #[apple] pub i32, #[apple] pub i32, );

[derive(Clone)]

pub enum Bar { #[orange] X(i32), #[orange] Y(i32), }

[derive(Debug)]

pub struct Baz( #[apple] pub i32, #[apple] pub f32, #[apple] pub i32, );

[derive(Clone)]

pub enum Qux { #[orange] A(i32), #[orange] B(i32), #[orange] C(i32), } ```

Instead of typing out #[orange], #[apple], and pub, repeatedly for each item declaration, you could simply write:

```rust use deriveless::deriveless;

derive_less! { #[derive(Debug)] pub struct ... { #[apple] pub ... } #[derive(Clone)] pub enum ... { #[orange] ... }

struct Foo(i32, i32);
enum Bar {
    X(i32),
    Y(i32),
}
struct Baz(i32, f32, i32);
enum Qux {
    A(i32),
    B(i32),
    C(i32),
}

} ```

You can also mix in derives that only apply to certain items/variants/fields, e.g:

```rust use deriveless::deriveless;

derive_less! { #[derive(Debug)] pub struct ... { #[apple] pub ... } #[derive(Clone)] pub enum ... { #[orange] ... }

struct Foo(i32, i32);
enum Bar {
    X(#[peanut] i32),
    Y(i32),
}
#[derive(PartialEq, PartialOrd)]
struct Baz(i32, f32, i32);
enum Qux {
    A(i32),
    B(i32),
    C(i32),
}

} ```

Limitations

Currently only supports: * Tuple structs * Unit structs * Enums with unnamed or unit fields

While structs and enums can take multiple #[...], e.g.:

```

[hello] #[world] struct ... { ... }

```

Fields and variants accept at most one #[...] due to current restrictions in macro_rules!. In other words, this does not work at the moment:

struct ... { #[hello] #[world] ... }

Future work

Handle more cases by either rewriting the derive_less! macro using Rust's procedural macro interface or through a build-script that generates declarative macro code.