Agda vs Why3
Agda
wiki.portal.chalmers.seWhy3
why3.orgSide by side
| Figure | Agda | Why3 |
|---|---|---|
| Price from | — | Free |
| Free plan | — | Yes |
| Free trial | — | — |
| Open source | — | — |
| Web | Yes | Yes |
| Windows | Yes | Yes |
| macOS | Yes | — |
| Linux | Yes | Yes |
| API | — | Yes |
| Self-hosted | Yes | Yes |
| Plans published | 0 | 1 |
| Spec score · Formal Verification Tools | 8.1 (#6) | 8.0 (#12) |
| Development | The Agda development center is the Logic and Types group at Chalmers and the University of Gothenburg, and the project is open source. | Why3 is developed by the Inria Toccata team, a joint research team of Inria Saclay-Île-de-France, Université Paris-Saclay, and CNRS. |
| Editor integrations | Interactive editor support is listed for Emacs, Visual Studio Code, Neovim, and Vim; Emacs is identified as the most tested. | Why3 distributions include configuration files for Emacs and Vim, plus shell completion files for bash and zsh. |
| Standard library | The Agda standard library is optional, and Agda works without it. | Why3 includes logical theories and programming data structures such as arrays, queues, and hash tables. |
| Support | The Agda wiki directs users to ask questions on the Agda mailing list or Agda Zulip server. | The project provides a user mailing list, a Zulip chat, and a bug tracking system. |
Plans
In their own words
Why3
Why3 is a platform for deductive program verification. It uses WhyML to express programs and specifications, then works with external automated or interactive theorem provers to discharge verification conditions. WhyML supports preconditions, postconditions, assertions, and loop invariants, alongside logical theories and data structures such as arrays, queues, and hash tables. External provers need to be installed and configured separately. Why3 can be extended with support for new provers and used as a software library through its OCaml API. WhyML programs can be extracted automatically into correct-by-construction OCaml programs, and WhyML is also used as an intermediate language for verification of C, Java, Rust, and Ada. TryWhy3 provides a JavaScript version that runs in a browser. Installation options include Opam, Docker, source compilation, and listed Debian, Fedora, and Ubuntu packages. Its graphical interface saves proof attempts and transformations in an XML file and can replay obsolete attempts. Why3 is free and open source under GNU LGPL 2.1 with a special linking exception. Loop invariant inference is a work in progress, and many features remain very limited.