Struct Reified 

pub struct Reified<'brand, T>
where
    T: ?Sized,
{ /* private fields */ }

A branded token carrying a reified value.

The lifetime 'brand is existential, created fresh by each call to reify and prevented from escaping the callback by the higher-rank bound for<'brand>. This mirrors Haskell’s forall s. Reifies s a => Proxy s -> r scoping.

The PhantomData carrying fn(&'brand ()) -> &'brand () makes 'brand invariant, preventing the compiler from shrinking or growing it to unify with any other lifetime. This is what makes the brand unique.

Examples

use reify_reflect_core::reify;

reify(&"hello", |token| {
    assert_eq!(*token.reflect(), "hello");
});

The token cannot escape:

use reify_reflect_core::reify;

let escaped = reify(&42, |token| {
    token // ERROR: borrowed data escapes the closure
});

Implementations

impl<'brand, T> Reified<'brand, T>

where T: ?Sized,

pub fn reflect(&self) -> &T

Reflect the reified value back to a runtime reference.

This is the Rust equivalent of Haskell’s reflect :: Reifies s a => proxy s -> a.

The branded lifetime ensures this reference cannot outlive the reify callback that created this token.

Examples

use reify_reflect_core::reify;

let doubled = reify(&21i32, |token| {
    token.reflect() * 2
});
assert_eq!(doubled, 42);