My programming language

This is an experimental programming language used for learning, written in OCaml 4.06.1.

Current features

• Simple arithmetics (+, -, *, /, >, <) with precences
• int and bool types
• let bindings and if expressions
• Closures fun x: int -> x*x
• Strict, static typechecker
• Partial evaluation:
• Multiple argument functions
• Print type of arbitrary expressions
• Unit type
• Tuples
• REPL

$ dune build repl.exe && dune exec ./repl.exe
> let a = ((fun x:(int) -> fun y:(int) -> x+y) 12) in a 122
int :: (Eval.Int 134)

> (fun x:(int->int->int) -> x 4 5) (fun x:(int) y:(int) -> x+y)
int :: (Eval.Int 9)

> (fun x:(int->int*int->int) -> (x 1 (1,1))+1) (fun x:(int) y:(int*int) -> 99)
int :: (Eval.Int 100)

Planned features

Usability

• Better syntax errors, OMG PLEASE, especially in * (Kleene star) rules
• Better typechecking errors

Syntax Sugar

• Recursive functions

Typesystem

• Use a typed AST to build the base for type inference
• Records
• Sum types
• Lists

Recusive types

• Recusive types

Polymorphism

• Hindley-Milner type system on System F

Long term goals

• Explore structural vs nominal typing
• Linear types
• Typeclasses
• Algebaic effects
• Concurrency and Parallelism (API via algebraic effects, monads)
• Dependent types
• Compilation to:
  • Assembly
  • LLVM
  • C
  • Go
  • JS
• Virtual machine (maybe written in rust)

Resources

• Types and programming languages (Benjamin C. Pierce)
• Programming language Zoo
• Modern Compiler implementation in ML (Andrew Appel)