Note: this project is an experimental proof of concept, not a fully designed and specified programming language.

Stellogen is a logic-agnostic programming language based on term unification. It has been designed from concepts of Girard's transcendental syntax programme.

• naturally describe state transitions and logic programs as a sort of syntactic tiling system;
• dynamically/statically typed but without primitive type nor type systems, by using very flexible assert-like expressions defining sets of tests to pass;
• both program execution and typechecking rely on a minimal kernel using term unification.

It draws inspiration (or try to draw inspiration) from:

• Prolog/Datalog (for unification-based computation);
• Smalltalk (for message-passing, object-oriented paradigm and minimalism);
• Coq (for proof-as-program paradigm and iterative programming with tactics);
• Scheme/Racket (for minimalism and metaprogramming);
• Haskell/Ruby (for syntax).

binary =
  -i(e) ok;
  -i(0:X) +i(X);
  -i(1:X) +i(X).

'input words
e :: binary.
e = +i(e).

000 :: binary.
000 = +i(0:0:0:e).

010 :: binary.
010 = +i(0:1:0:e).

110 :: binary.
110 = +i(1:1:0:e).

a1 = galaxy
  initial:
    -i(W) +a(W q0).
  final:
    -a(e q2) accept.
  transitions:
    -a(0:W q0) +a(W q0);
    -a(0:W q0) +a(W q1);
    -a(1:W q0) +a(W q0);
    -a(0:W q1) +a(W q2).
end

show process e.   a1. kill. end
show process 000. a1. kill. end
show process 010. a1. kill. end
show process 110. a1. kill. end

More examples can be found in examples/.

This project is still in development, hence the syntax and features are still changing frequently.

To learn more about the current implementation of stellogen:

• French guide (official): https://tsguide.refl.fr/
• English guide: https://tsguide.refl.fr/en/

You can either download a released binary (or ask for a binary), install using opam, or build the program from sources.

Install opam.

Install the latest development version of the package from this repo with

opam pin tsyntax https://github.com/engboris/stellogen.git

Install opam and OCaml from opam : https://ocaml.org/docs/installing-ocaml

Install dune:

opam install dune

Install dependencies

opam install . --deps-only --with-test

Build the project

dune build

Executables are in _build/default/bin/.

Install dependencies

nix develop

Build the project

dune build

Executables are in _build/default/bin/.

Assume the executable is named sgen.exe. Interpreter Stellogen programs with:

./sgen.exe <inputfile>

or if you use Dune:

dune exec sgen -- <inputfile>