gf-core/transfer

Some features of the Transfer language:

* Purely functional
* Dependent types
* Eager evaluation
* Generalized algebraic datatypes
* Metavariables
* Records with subtyping
* Overloading by explicit dictionary passing
* Pattern matching by case expressions

Additional features in the front-end language:

* Disjunctive patterns
* do-notation
* Automatic derivation of some operations on user-defined GADTs:
  - Compositional maps and folds
  - Equality
  - Ordering
  - Showing
* Pattern equations
* Operator syntax for common functions, most are overloaded



Differences between Transfer and Cayenne:

* Cayenne has a more advanced module system

* Cayenne has mutually recursive record fields

* Cayenne erases type arguments before running

* Transfer is eager, Cayenne is lazy

* Transfer has GADTs (inductive families)

* Transfer has metavariables

* Transfer has record patterns

* Transfer has disjunctive patterns

* Transfer has derivation of compositional functions

* Transfer has a standard library which uses a hierarchy
  of "type classes"