peach-lang
v0.4.1
Published
A tiny functional language
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peach
A statically typed functional language.
fib =
0 => 1
1 => 1
x => (+ (fib (- x 1)) (fib (- x 2)))
(map fib [0 1 2 3 4 5 6 7 8 9 10])
# [ 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89 ]
Syntax
Peach is inspired by JavaScript, Elm, Clojure and @bodil's BODOL, which I learned about from this awesome talk.
# assignment
x = 2 # 2
# equality
(== x 2) # true
# maths and stuff
(* x 2) # 4
# conditionals
if ((< x 10))
`little`
else if ((< x 20))
`medium`
else
`large`
# functions
double = (x => (* x 2))
(map x (x => (pow x 2))) # [2 4 8 16]
# currying
double-all = (map double)
(double-all [1 2 3 4]) # (2 4 6 8)
# pattern matching
(fn fib
0 => 1
1 => 1
x => (+ (fib x - 2) (fib x - 1))
)
(fn starts-with-one
[1|_] => true
_ => false
)
# tail call optimisation
# n: the accumulating factorial
# x: a decrementing iteration count
factorial =
(n, 1) => n
(n, x) => (factorial (* n x) (- x 1))
(factorial 1 32768) # Infinity, because JavaScript. Better than a stack overflow!
Semantics
- Static typing (with Damas-Hindley-Milner type inference)
- Pure functions
- Everything is an expression
- Immutability
- Strict evaluation
- Currying
Features
- Minimal syntax
- A tree-based JavaScript interpreter
- REPL
- Proper tails calls
Plans
Coming soon:
- Type hint syntax
- More stdlib
- Algebraic data types
And then:
- JavaScript interop
- JavaScript code generation
- Lazy sequences
- IO
One day:
- Efficient bytecode interpreter
- Interactive debugger
- Immutable data structures with structural sharing
- Self-hosting
Develop
Use Node 6+.
npm install
npm test