Isabelle

This is the language of the [Isabelle](https://isabelle.in.tum.de/) proof assistant. It is a superset of an ML dialect. 

Here are some repositories using Isabelle:

* https://github.com/formare/auctions/
* https://github.com/FormalTheology/GoedelGod/
* https://github.com/avigad/isabelle/tree/master/Analysis
* https://github.com/larsrh/hol-falso
* https://github.com/iislucas/isaplib/tree/master/isabelle/isaplib
* https://github.com/NicoleRauch/Isabelle
* https://github.com/caylee-hogg/isabelle-semantics
* https://github.com/meiersi/scyther-proof/tree/master/data/isabelle/src

This is my first contribution to “linguist” (a few more to follow); I'll be happy to learn of anything I could improve.