[harrytuttle]

We use three DSLs to construct our application, all of which have custom hand-written parsers for performance reasons. One for extending UI, one for extending the core domain model and one for defining business workflows and events. We have 65,000 separate customisations at the moment so this is a big win for us.

You throw all these into a our metadata store and point the software at it and at runtime it throws out a desktop (WPF), mobile (web) and web version of our app which are all tightly integrated.

We built this because everyone of our clients needs heavy process level customisation yet we want to maintain a SaaS model.

Not toy languages here although you'll never see them on github.