From cb7bcfad4ab0041aaf3fde3185e27ee46bb37788 Mon Sep 17 00:00:00 2001 From: JSDurand Date: Tue, 15 Nov 2022 12:01:28 +0800 Subject: Initial commit Basic GNU standard files are added, and we now stop worrying about monadic anamorphisms. The current focus is on testing the correctness of the algorithm, so I need convenient support for manipulating, interpreting, examining, and per chance animating nondeterministic automata. --- receme/src/coralgebra.rs | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) create mode 100644 receme/src/coralgebra.rs (limited to 'receme/src/coralgebra.rs') diff --git a/receme/src/coralgebra.rs b/receme/src/coralgebra.rs new file mode 100644 index 0000000..a4a73d2 --- /dev/null +++ b/receme/src/coralgebra.rs @@ -0,0 +1,28 @@ +//! This file defines the behaviours of R-co-algebras. +//! +//! For a functor F, an R-co-algebra is a natural transformation from +//! the identity functor to F1, where F1 is the functor that sends T +//! to F(F(T) + T), where the + is the categorical co-product, +//! represented in Rust as `Result`. And the F(T) variant means to +//! short-circuit the expansion. + +use crate::functor::Functor; + +/// An R-co-algebra is a function from T to F(Result). +/// +/// This is a "trait alias". Since Rust does not support trait alias +/// yet, we define an empty trait with an automatic implementation. +pub trait Coralgebra: FnMut(T) -> G +where + F: Functor, + G: Functor>, +{ +} + +impl Coralgebra for R +where + F: Functor, + G: Functor>, + R: FnMut(T) -> G, +{ +} -- cgit v1.2.3-18-g5258