Babel is an exercise to understand expressive type systems. The goal is to build an expressive, call by value programming language which does not have a runtime system.

Design goals

• Keep the language/compiler simple
• Keep semantics clear
• Be as UNORIGINAL as possible

Features

• static typing
• parametric polymorphism
• type inference
• value restriction
• monomorphization
• C based ABI
• C interoperability
• Records
• constrained parametric polymorphism (type classes)
• affine types
• references
• pattern matching
• functors
• metaprgramming

Unsupported

• Mutually recursive functions that are not at the top level. In theory we can do dependency analysis o detect mutual recursion and then group the mutually recursive functions. Creating the groups can reorder side effects and so is not safe to do in an impure language.

Where I diverge from literature

• Type constructors and expr applications have arity this is to allow uncurrying to work.