scala/Optional side-effect.ipynb

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 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Optional side-effect"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "\u001b[36mnameOpt\u001b[0m: \u001b[32mOption\u001b[0m[\u001b[32mString\u001b[0m] = \u001b[33mSome\u001b[0m(\u001b[32m\"Amir\"\u001b[0m)\n",
       "defined \u001b[32mfunction \u001b[36mprintName\u001b[0m"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "val nameOpt = Option(\"Amir\")\n",
    "\n",
    "def printName(name: String) = println(name)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Amir"
     ]
    },
    {
     "data": {
      "text/plain": []
     },
     "metadata": {},
     "output_type": "display_data"
    },
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "\n"
     ]
    }
   ],
   "source": [
    "nameOpt.foreach(printName)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "\u001b[36manotherOpt\u001b[0m: \u001b[32mNone\u001b[0m.type = None"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "val anotherOpt = None"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": []
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "anotherOpt.foreach(printName)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "This is a great pattern for optinally generating side-effects given an option that you take from the command line, namely in conjunction with [scallop](https://github.com/scallop/scallop)."
   ]
  }
 ],
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