# the mechanicals

Various implementations of the lambda calculus (and friends).

The code here is hopefully pretty readable: but makes heavy use of quasiquoting.
For an introduction, see [*Explaining Lisp's quoting without getting tangled*](quasiquoting).

* [~] LC: The untyped lambda calculus.
* [x] STLC: The simply-typed lambda calculus.
* [x] STLC-ext: Simple extensions. Sums, products, lists, ascryptions.
* [ ] STLC-fix: General recursion.
* [ ] STLC-sub: Subtyping. Structural records, intersective unions, implicit typeclasses, ⊤, ⊥.
* [ ] STLC-rec: Recursive types. Also sums, products, ascryption.
* [x] STLC-ref: References.
* [x] STLC-pred: Higher-order *predicative* references. Terminating.
* [ ] STLC-imp: Higher-order *impredicative* references. Terminating.
* [ ] STLC-rc: References with reference counting.
* [ ] STLC-gc: References with a tracing garbage collector.
* [ ] STLC-own: References with Rust-style ownership.
* [ ] STLC-eff: Effects.
* [ ] STLC-class: Typeclasses
* [~] SKI: The SKI combinator calculus.
* [~] Iota, Jot, Zot: Implementations of Chris Barker's languages.
* [~] Aviary: Various combinators and constructions of equivalence.


[quasiquoting]: https://cadence.moe/blog/2022-10-17-explaining-lisp-quoting-without-getting-tangled