Morrow

Morrow is small programming language designed for experimentation with advanced type system concepts. In particular, extensible polymorphic records and variants, combined with impredicative higher-ranked type inference. This combination leads to an expressive core language that is able to express many progamming language concepts directly without specific extensions.

The Morrow interpreter is work in progress, but it already supports impredicative higher-rank type inference, existential types, polymorphic kinds, and extensible records and variants. As such, the interpreter is a nice vehicle to experiment with those features.

• Read a short introduction.
• Download the interpreter.

There are currently two papers that describe more of the design of the type system of Morrow:

• Extending MLF with qualified types.
• First-class polymorphism with existential types.

Have fun playing with types,
  Daan Leijen

"Apr 10 2006"