Crate reify_reflect 

A unified, fully-safe ecosystem for moving values between Rust’s type level and value level.

This is the facade crate. It re-exports each of the focused crates in the workspace under a single namespace, so a single dependency on reify-reflect (with appropriate features) is enough to use everything. If you only need one piece, depending on the focused crate directly gives you a smaller build.

What is “reification” and “reflection”?

Two complementary directions:

• Reflection is type → value. A type like S<S<S<Z>>> encodes the number 3 at compile time; core::Reflect::reflect hands you 3 at runtime.
• Reification is value → type. A u64 known only at runtime can be lifted into a callback in which it is genuinely a const N: u64. See const_reify (re-exported as [const_bridge] when the const-reify feature is enabled).

Everything here is #![deny(unsafe_code)]. There is no unsafe, no compiler-internal layout assumption, and no unsafeCoerce-style trick. The Rust borrow checker enforces what GHC’s parametricity enforces in Haskell’s reflection library.

Module map

Module	Crate	Use it for
core	reify_reflect_core	The Reflect trait, the reify scoping function, the Reified branded token, and the RuntimeValue enum.
nat	reflect_nat	Peano naturals (Z/S<N>), type-level booleans, heterogeneous lists, with optional frunk/typenum bridges.
graph	reify_graph	Convert Rc<RefCell<T>> or Arc<Mutex<T>> graphs to and from a flat node+edge form, preserving sharing and cycles.
context	context_trait	Swap out Ord, Hash, Display (or any user-defined trait) for one block of code via WithContext.
async_trace	async_reify	Wrap futures to record poll events and turn them into an inspectable async step graph.
[const_bridge] (feature const-reify)	const_reify	Dispatch a runtime u64 in 0..=255 to the matching const N: u64 monomorphization, safely.

For the #[derive(Reflect)], #[trace_async], and #[reifiable] proc macros, depend on reflect-derive, async-reify-macros, and const-reify-derive respectively (or enable the relevant features).

Quick start

Reflect a type-level number to a runtime value:

use reify_reflect::core::{Reflect, RuntimeValue};
use reify_reflect::nat::{S, Z};

type Three = S<S<S<Z>>>;
assert_eq!(Three::reflect(), RuntimeValue::Nat(3));

For deeper walkthroughs, see the guides and the narrative blog post in the source tree.

Feature flags

Feature	Default	Effect
serde	yes	Enables Serialize/Deserialize impls in graph and async_trace.
const-reify	no	Enables the [const_bridge] module. Adds 256 monomorphizations to compile time.
typenum	no	Bridge between nat and the typenum crate.
frunk	no	Bridge between nat and frunk’s HList.
full	no	All of the above.

Modules

async_trace

Async computation tracing and step graph extraction.

context

Runtime-synthesized trait instances scoped to callbacks.

core

Core traits and types: Reflect, reify, Reified, RuntimeValue.

graph

Rc<RefCell<T>> graph reification and reconstruction.

nat

Type-level naturals (Z, S), booleans (True, False), and heterogeneous lists (HNil, HCons).