Haskell-Frege Interpreter for Apache Zeppelin

Install

1. Unzip archive to interpreter folder in zeppelin directory
2. Open Zeppelin UI and go to Interpreter page
3. Click Create button and add new interpreter with name haskell and group frege

Examples

Simple expression

%haskell
3 * 9
--
> 27

Lazy expression

%haskell
print [x*x | x <- [1..10]]
---
> [1, 4, 9, 16, 25, 36, 49, 64, 81, 100]

Multi-line expression

Normally we cannot mix definitions and method call in the same paragraph but there is one trick. If there is z_display function defined in paragraph then interpreter will call that function when all definitions are compiled. The z_display method will apply show function to display the result.

%haskell

import Data.List

fib :: Int -> Int
fib n = xs !! n
    where xs = 1 : 1 : zipWith (+) xs (tail xs)

z_display = fib 10
---
> 89

Program

At the moment interpreter doesn't support normal main method and you need to use z_main instead.

%haskell
z_main :: IO ()
z_main = do
  print "hello world"
  println "!!!"
---
> hello world!!!