prismqueer

prismqueer

A typed transformation pipeline. The Prism trait + Beam carrier + Optic concrete beam. Zero deps above the foundation; staged transformations compose with compile-time type checking.

Install

cargo add prismqueer

Optional features:

• optics — classical optics (Lens, Iso, Traversal, Fold, Setter, OpticPrism) expressed through the Prism trait.
• bundle — the principal-bundle tower (Fiber → Connection → Gauge → Transport → Closure) and IdentityPrism. Implies optics.
• lambda — a tiny content-addressed lambda calculus + #[derive(Lambda)].
• pq — the typed pq wire DSL (Target / Filter / Output) with serde + JSON Schema derivation.
• lapack — dispatch the KernelSpec / SpectralDimension machinery to Fortran via a small cc build.

What it gives you

• Prism — a trait with three associated beams and three methods (focus, project, settle). The compiler enforces that each stage's output type matches the next stage's input type.
• Beam — the semifunctor over Imperfect. Carries a value, the input that produced it, and accumulated loss. Failure beams are dark: a fixpoint under smap and next.
• Optic<In, Out, E, L> — the standard Beam implementation.
• apply — run a prism end-to-end: focus, then project, then settle.
• IdentityPrism — the identity element. (Feature: bundle.)

Example

use prismqueer::{apply, Beam, Optic, Prism};

struct CountPrism;

impl Prism for CountPrism {
    type Input     = Optic<(), String>;
    type Focused   = Optic<String, Vec<char>>;
    type Projected = Optic<Vec<char>, usize>;
    type Refracted = Optic<usize, String>;

    fn focus(&self, beam: Self::Input) -> Self::Focused {
        let s = beam.result().ok().unwrap().clone();
        beam.next(s.chars().collect())
    }
    fn project(&self, beam: Self::Focused) -> Self::Projected {
        let n = beam.result().ok().unwrap().len();
        beam.next(n)
    }
    fn settle(&self, beam: Self::Projected) -> Self::Refracted {
        let n = *beam.result().ok().unwrap();
        beam.next(format!("{n} chars"))
    }
}

let out = apply(&CountPrism, Optic::ok((), "hello".to_string()));
assert_eq!(out.result().ok(), Some(&"5 chars".to_string()));

Full API on docs.rs.

Why prismqueer

The crate was internally prism-core during development; that name was taken on crates.io by an unrelated project. The cascade renamed. The math is unchanged; the kernel is the same kernel.

Status

Pre-1.0. The trait surface is shaped by ongoing substrate work in the mirror and prism repositories. Breaking changes are possible at any minor version until 1.0; minor versions track substrate movement, not LTS.

License

Apache-2.0.