ulang prototype

Minimal un(i)typed functional programming language based on tagged values and pattern matching.

See src/ulang for some examples on the syntax.

Features

• distinguish data constructors and identifiers by capitalizing the former
• flexible mixfix syntax including precedences
• pattern matching in function definitions, match expressions, let bindings, and lambdas with optional conditions
• list/tuple literals
• builtin unit test syntax
• a primitive interactive repl
• ad-hoc overloading of functions

Library + Code

• primitive data types booleans, option, (unary) numerals, lists with useful functions
• a red-black tree implementation
• regular expression matching
• combinator parsing
• a simplifying prover for propositional logic (incomplete in the logical sense)

Expression Syntax examples (see also src/scala/ulang/syntax.scala)

f x y
\x -> f x

/* abstractions can pattern match and take several cases */
\ Zero m -> Zero | (Succ n) m -> ...
if p then a else b 

// tuple, list literals
(1, 2)
[A, B, C]

(<) // infix identifier (can be used as local variable) 

match a with
  p -> e
| s -> d

Currently broken

// parallel let
let x = A, y = B in e
// destructuring let
let (x,y) = unzip zs in ...