lulu

lulu is a Lisp-like programming language that compiles to JavaScript.

Examples

Hello World!

(console.log "Hello World!")

Hello World!

Conditionals

(let coinToss (gt (Math.random) 0.5))
(console.log (if coinToss "Heads" "Tails"))

Heads

User Input (Browser)

(let name (prompt "What's your name?"))
(console.log (concat "Hello " name "!"))

What's your name? Jason
Hello Jason!

More examples

User Input (Node)

(let readline (require "readline"))
(let rl (readline.createInterface
         (dict
          (list "input" process.stdin)
          (list "output" process.stdout))))

(rl.question "What's your name? "
             (lambda (name)
               (console.log (concat "Hello " name "!"))
               (rl.close)))

What's your name? Jason
Hello Jason!

setTimeout

(console.log
 (map (lambda (str i)
        (let factor (mul i 800))
        (setTimeout (lambda () (console.log str))
                    factor)
        factor)
      (list "What if we put our minecraft"
            "beds next to each other?"
            "haha jk"
            "unless? (〃∀〃)ゞ")))

[ 0, 800, 1600, 2400 ]
What if we put our minecraft
beds next to each other?
haha jk
unless? (〃∀〃)ゞ

Functions

(defun factorial (n)
  (if (eq n 0)
      1
    (mul n (factorial (dec n)))))

(console.log (factorial 5))

120

Constructor

(defun Person (name age)
  (let this.name name)
  (let this.age age)
  ())

(console.log (new Person "Kiki" 12))

Person { name: 'Kiki', age: 12 }

Building from source

stack build
stack run input.lulu output.js
node output.js

Function List

Functions are defined in src/LuluInclude.hs.

Function	Description
add	Adds two numbers
sub	Subtracts two numbers
mul	Multiplies two numbers
div	Divides two numbers
mod	Returns remainder after division of two numbers
inc	Add 1
dec	Subtract 1
eq	Loose equality
lt	True if left hand side is less than right hand side
lte	True if left hand side is less than or equal to right hand side
gt	True if left hand side is greater than right hand side
gte	True if left hand side is greater than or equal to right hand side
and	Logical and
or	Logical or
xor	Logical xor
list	Constructs an array
range	Create an array of numbers within a range. (last number excluded)
length	Get length of string, array, what have you
concat	Concatenate strings, arrays, what have you
join	Join an array (or array like) with a given separator
fromList	Creates an object given a list of key value pairs
dict	fromList, except with a variable argument list
assoc	Add or update an entry in an object
dissoc	Unset an entry in an object
map	Transforms each element in an array with a given callback function
filter	Creates an array with elements that pass a predicate
reduce	Execute a reducer function for each element in an array

BNF Grammar

         <program> ::= <opt-whitespace> | <opt-whitespace> <sexpr> <program>
           <sexpr> ::= <atom> | "(" <whitespace> <args> <whitespace> ")"
            <args> ::= <sexpr> | <sexpr> <whitespace> <sexpr>
            <atom> ::= <number> | <name> | <string>
 
          <number> ::= <digit> | <digit> <number> | <number> "." <number>
            <name> ::= <alpha> | "_" | <name> <alphanumeric> | <name> "_" | <name> "." <name>
          <string> ::= '"' <text> '"'
            <text> ::= "" | <normal-char> <text> | "\"" <text>
     <normal-char> ::= any character that isn't '"' or '\\'

  <opt-whitespace> ::= "" | <whitespace>
      <whitespace> ::= <whitespace-chars> | <whitespace-chars> <whitespace>
<whitespace-chars> ::= " " | "\n" | "\r"
    <alphanumeric> ::= <alpha> | <digit>
           <alpha> ::= "a" | "b" | ... | "z" | "A" | "B" | ... | "Z"
           <digit> ::= "0" | "1" | ... | "9"