JoJo's Bizarre Programming Adventure

DIO: ZA WARUDO is full of languages without good type system, we don't need anymore!

JOJO: Just one more!

DIO: Do you care about HUMANITY! JOJO?

JOJO: I REJECT MY HUMANITY, DIO!

Features

A dynamic language for learning, teaching and prototyping.

• 🚧 simply typed with subtype
• object oriented, but no side-effect over objects
• implemented in rust by a dynamic threaded code interpreter
• uses rust's Arc as garbage collector
• sexp as syntax -- enabling a lisp-like macro system
• 🚧 pattern matching
• 🚧 simple FFI to rust library
• 🚧 forth like threading macro
  • drop dup over tuck swap
    • Oh tis so bizarre ~

Getting start

With nightly rust toolchain :

cargo install jojo

Contributing

Contributions are welcome! (The code base is still simple for now.)

• Give suggestions in issues.
• Or simply throw pull requests to me!

I will write style-guide and hacking-guide for my contributors :)

See jojo-history for history of this project.

Examples

Square Roots by Newton's Method

(square x) = (mul x x)

(average x y) = (div (add x y) 2)

(= (sqrt-iter guess x)
   (if (good-enough-p guess x)
     guess
     (sqrt-iter (improve guess x) x)))

(improve guess x) = (average guess (div x guess))
(good-enough-p guess x) = (lt (abs (sub (square guess) x)) 0.001)
(sqrt x) = (sqrt-iter 1 x)

(sqrt 9)
(sqrt (add 100 21))
(square (sqrt 1000))

Simpson's Rule for numerical integration

(cube x) = (mul x (mul x x))

(= (sum term a next b)
   (if (gt a b)
     0
     (add (term a)
          (sum term (next a) next b))))

(= (simpson-integral f a b n)
   (= h (div (sub b a) n))
   (= (simpson-coefficient k)
      (cond [(or (eq 0 k) (eq n k)) 1]
            [(odd-p k) 4]
            [(even-p k) 2]))
   (= (simpson-term k)
      (mul (simpson-coefficient k)
           (f (add a (mul k h)))))
   (mul (sum simpson-term 0 inc n)
        (div h 3)))

(= assert-delta
   (macro [body]
     (= delta (car body))
     (= a (car (cdr body)))
     (= b (car (cdr (cdr body))))
     `(assert (lt (abs (sub ~a ~b)) ~delta))))

(assert-delta 0.0001
  (simpson-integral cube 0 1 100)
  (div 1 4))

Notes

• 🚧 (2018-07-22) Semantic of De Bruijn Notation and Bizarre Syntax Adventure
  • Discussions about syntax design of programming language.

🚢 ✈ ADVENTURE️ ⛴️ ⛵

• SICP
• 🚧 EOPL
• 🚧 journey-into-cryptography
• 🚧 microkanren

See adventure for more code examples.

LICENSE

GPLv3