wrapper-lite

The new type idiom gives compile time guarantees that the right type of value is supplied to a program.

This crate provides a simple macro for you to create a wrapper over any type.

Notable changes since v0.3.0

• Starting from v0.3.1, the complex usage now accept any inner field name (but must be the first one).

  wrapper_lite::wrapper!(
      #[wrapper_impl(AsRef<str>)]
      pub struct TestWrapperComplex {
          value: String, // <-- can be any name now, not necessarily "inner"
          _marker: ::core::marker::PhantomData<()>,
      }
  );

• In v0.3.1, we introduce #[repr(align(cache))] attribute for the wrapper struct.

  wrapper_lite::wrapper!(
      #[repr(align(cache))]
      pub struct AlignedWrapper(u8);
  );

  See the docs for usage details.

Migrate from v0.2.X

1. The macro now only accepts valid Rust struct syntax.

   wrapper_lite::wrapper!(
       pub struct TestWrapper1(u8); // <-- note the semicolon, now it's required
   );

   wrapper_lite::wrapper!(
       pub struct TestWrapper2 {
           inner: u8,
       }
   );

2. When there's no default value specified, we cannot implement the From trait for the wrapper type, and now it's a hard error.

   wrapper_lite::wrapper!(
       #[wrapper_impl(From)]
       pub struct TestWrapperComplex<'a, 'b> {
           inner: String,
           _a: ::core::marker::PhantomData<&'a ()>,
           _b: ::core::marker::PhantomData<&'b ()>,
       }
   );

Migrate from v0.1.X

To make cargo-fmt happy, starting from v0.2.0, the following usage which is not a valid Rust struct syntax is no longer accepted.

wrapper_lite::wrapper!(
    pub ExampleWrapper(u8)
);

Instead:

wrapper_lite::wrapper!(
    pub struct ExampleWrapper(u8);
);

Now we can format the macro content with cargo fmt!

License

Licensed under either of:

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT License (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.