prismqueer 🌈

A typed transformation pipeline in Rust. Carry a value, the input that produced it, and the loss accumulated along the way — through a chain that the compiler checks end-to-end.

This workspace ships three crates to crates.io: terni, prismqueer, and prismqueer-projections.

Crates

terni

Result extended with partial success. Three states: Success, Partial(value, loss), Failure. The Loss trait measures what didn't survive a transformation. Standalone, zero deps on the rest of the workspace. Source: imperfect/.

prismqueer

The Prism trait, the Beam carrier, and the Optic concrete beam. A Beam is a semifunctor over Imperfect; a Prism is three staged transformations (focus, project, settle) over beams. They compose into pipelines whose type-shape is checked at compile time. Source: prismqueer/.

prismqueer-projections

Proc-macros for prismqueer: #[derive(Prism)], #[derive(Lambda)], declaration!{}. Source: projections/.

Dependency direction

terni (standalone, zero deps)
^
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prismqueer-projections (proc-macros; reference prismqueer paths in their output)
^
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prismqueer (depends on terni + prismqueer-projections)

Example

use prismqueer::{apply,Beam,Optic,Prism};// A trivial prism: focus splits the input into chars,// project counts them, settle renders the count.structCountPrism;implPrismforCountPrism{typeInput = Optic<(),String>;typeFocused = Optic<String,Vec<char>>;typeProjected = Optic<Vec<char>,usize>;typeRefracted = Optic<usize,String>;fnfocus(&self,beam:Self::Input) -> Self::Focused{let s = beam.result().ok().unwrap().clone();
beam.next(s.chars().collect())}fnproject(&self,beam:Self::Focused) -> Self::Projected{let n = beam.result().ok().unwrap().len();
beam.next(n)}fnsettle(&self,beam:Self::Projected) -> Self::Refracted{let n = *beam.result().ok().unwrap();
beam.next(format!("{n} chars"))}}let result = apply(&CountPrism,Optic::ok((),"hello".to_string()));assert_eq!(result.result().ok(),Some(&"5 chars".to_string()));

Each stage's output type feeds the next stage's input type. A type mismatch between stages is a compile error, not a runtime panic.

Tests

Workspace tests across all features:

cargo test --workspace --all-features

License

Apache-2.0 across the workspace. See each crate's LICENSE.