utf16_lit

Lets you change a standard Rust string literal (utf8) into a utf16 value at compile time.

This crate doesn't use syn or quote, so it builds very fast.

Stability: Not Really

Currently, "function-like" proc-macros are not so great in rust. They must only be used in "item position" (at the top level of a module), not in "statement position" (a line of their own within a block of code) or "expression position" (as a sub-portion of an expression within a statement). This makes the current usage of the proc-macro quite poor.

Once function-like proc-macros are available in expression position, the library will be updated so that the usage produces an expression. This will be a completely breaking change.

```rust // Currently the usage is like this: utf16_lit!(EXAMPLE, "example");

// our goal usage is something like this pub const EXAMPLE: &[u16] = utf16_lit!("example");

// and also things like this should be possible fn isfoo(input: &[u16]) -> bool { input == utf16lit!("foo") } ```

Tracking Issues of Note: * Tracking issue for procedural macros and "hygiene 2.0" * Stabilize fn-like proc macros in expression, pattern and statement positions * Stabilize Span::mixed_site