BlackBox

BlackBox provides a repl for talking to Elm code that takes a string as input and produces a string as output:

    transform : String -> String

The supplied Blackbox.elm file provides an uninteresting transform function for demonstration purposes: it imitates the Unix command wc. You can modify the code of Blackbox to make it do whatever you like — factor an integer into primes, run an RPN calculator, compute statistics, etc.

Example using the default BlackBox:

    $ npm install -g elm-bb
    $ elm-bb

    > :help                 # show help screen

    > foo bar               # apply transform to "foo bar" -- report lines, words, chars
    1, 2, 7

    > :get src/repl.js      # load file into memory and apply transform to it
    42, 97, 863

    > :app                  # apply transform to contents of memory
    42, 97, 863

To uninstall, run npm uninstall elm-bb.

Running Blackbox from source

    $ sh make.sh  
    $ node src/repl.js
    > foo bar
    1, 2, 7

Customizing

For a customized BlackBox, proceed as described below.

Set up

First, make a directory somewhere — let's call it bb. Second, put the text below in a file package.json

{
  "name": "bb",
  "version": "1.0.0",
  "description": "",
  "main": "node_modules/.bin/elm-bb",
  "scripts": {
    "edit": "atom node_modules/elm-bb/src/BlackBox.elm",
    "build": "cd node_modules/elm-bb && sh make.sh",
    "elm-bb": "./node_modules/.bin/elm-bb",
    "link": "ln -s PATH_TO/src/repl.js /usr/local/bin/elm-bb"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "elm-bb": "^0.9.6 "
  }
}

If you wish, change 'atom' to your favorite editor. Third, run npm install. Test your installation with npm run elm-bb.

Edit and compile

First, edit ./node_modules/elm-bb/src/Main.elm. If package.json is configured to run your editor, you can say npm run edit.

Second, say npm run build.

You have now customized elm-bb and can test it with npm run elm-bb

Link

To install elm-bb as a system-wide command, edit PATH_TO in package.json, then say npm run link.