Add Optics

Based on second chapter of the book Optics by Example.

optics.ipynb

@@ -0,0 +1,212 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "# Optics\n",
+    "\n",
+    "## What are optics?\n",
+    "\n",
+    "Lenses, Folds, Traversals, Prisms and Isos are all types of Optics.\n",
+    "\n",
+    "## Strengths\n",
+    "\n",
+    "1. Composition\n",
+    "2. Separation of Concerns\n",
+    "3. Concision\n",
+    "4. Enforcing interface boundaries\n",
+    "5. Principled and mature ecosystem\n",
+    "\n",
+    "## Weaknesses\n",
+    "\n",
+    "1. Type-errors\n",
+    "2. Complex Implementation\n",
+    "3. Vast number of combinators\n",
+    "\n",
+    "## Some examples\n"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 14,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "30"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    },
+    {
+     "data": {
+      "text/plain": [
+       "[\"This one t...\",\"Nuff said.\",\"This is a ...\"]"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    },
+    {
+     "data": {
+      "text/plain": [
+       "27"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    },
+    {
+     "data": {
+      "text/plain": [
+       "\"Why Is A Raven Like A Writing Desk\""
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    },
+    {
+     "data": {
+      "text/plain": [
+       "(Just 300,Left (\"hello\",[1300,1500,1700]))"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    },
+    {
+     "data": {
+      "text/plain": [
+       "[1,8,3,6,5,4,7,2]"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    },
+    {
+     "data": {
+      "text/plain": [
+       "(\"eee\",\"hno\",\"orttw\")"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    },
+    {
+     "data": {
+      "text/plain": [
+       "[3,0,1,6]"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    },
+    {
+     "data": {
+      "text/plain": [
+       "What is your name?\n",
+       "What is your quest?\n",
+       "What is your favourite color?\n",
+       "(\"Sir Galahad\",\"To seek the holy grail\",\"Black I think\")"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "-- Required Language Extensions and imports\n",
+    "\n",
+    "{-# LANGUAGE TemplateHaskell #-}\n",
+    "{-# LANGUAGE FlexibleInstances #-}\n",
+    "{-# LANGUAGE FlexibleContexts #-}\n",
+    "{-# LANGUAGE RankNTypes #-}\n",
+    "{-# LANGUAGE ScopedTypeVariables #-}\n",
+    "{-# LANGUAGE TypeApplications #-}\n",
+    "{-# LANGUAGE TypeFamilies #-}\n",
+    "{-# LANGUAGE InstanceSigs #-}\n",
+    "\n",
+    "import Control.Lens\n",
+    "import Numeric.Lens\n",
+    "import Data.Bits.Lens\n",
+    "import Data.Data.Lens\n",
+    "\n",
+    "import Control.Applicative\n",
+    "import Data.Char as C\n",
+    "import qualified Data.Map as M\n",
+    "import qualified Data.Set as S\n",
+    "import qualified Data.Text as T\n",
+    "import qualified Data.List as L\n",
+    "\n",
+    "-- Below examples are taken from Chris Penner's Optics by Example\n",
+    "\n",
+    "-- View nested fields of some record type\n",
+    "\n",
+    "--- view (address . country) person\n",
+    "---\"Canada\"\n",
+    "\n",
+    "-- Update portions of immutable data structures\n",
+    "\n",
+    "-- set _3 False ('a', 'b', 'c')\n",
+    "-- ('a', 'b', False)\n",
+    "\n",
+    "-- These selectors compose!\n",
+    "-- We can perform a task over deeply nested subsets of data.\n",
+    "-- Let's sum all numbers which in a 'Left' within the right half of each tuple\n",
+    "\n",
+    "sumOf (folded . _2 . _Left) [(True, Left 10), (False, Right \"pepporoni\"), (True, Left 20)]\n",
+    "\n",
+    "let stories = [\"This one time at band camp\", \"Nuff said.\", \"This is a short story\"]\n",
+    "\n",
+    "over (traversed . filtered ((>10) . length)) (\\story -> take 10 story ++ \"...\") stories\n",
+    "\n",
+    "-- Summarize a list of numbers, subtracting the 'Left's, adding the 'Right's!\n",
+    "\n",
+    "sumOf (folded . beside negated id) [Left 1, Right 10, Left 2, Right 20]\n",
+    "\n",
+    "-- Capitalize each word in a sentence\n",
+    "\"why is a raven like a writing desk\" & worded . _head %~ toUpper\n",
+    "\n",
+    "-- Multiply every Integer by 100 no matter where they are in the structure:\n",
+    "(Just 3, Left (\"hello\", [13, 15, 17])) & biplate *~ 100\n",
+    "\n",
+    "-- Reverse the ordering of all even numbers in a sequence.\n",
+    "-- We leave the odd numbers alone!\n",
+    "[1, 2, 3, 4, 5, 6, 7, 8] & partsOf (traversed . filtered even) %~ reverse\n",
+    "\n",
+    "-- Sort all the characters in all strings, across word boundaries!\n",
+    "(\"one\", \"two\", \"three\") & partsOf (each . traversed) %~ L.sort\n",
+    "\n",
+    "-- Flip the 2nd bit of each number to a 0\n",
+    "[1, 2, 3, 4] & traversed . bitAt 1 %~ not\n",
+    "\n",
+    "-- Prompt the user with each question in a tuple,\n",
+    "-- then return the tuple with each prompt replaced with the user's input,\n",
+    "let prompts = ( \"What is your name?\"\n",
+    "                , \"What is your quest?\"\n",
+    "                , \"What is your favourite color?\"\n",
+    "                )\n",
+    "prompts & each %%~ (\\prompt -> putStrLn prompt >> getLine)"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Haskell",
+   "language": "haskell",
+   "name": "haskell"
+  },
+  "language_info": {
+   "codemirror_mode": "ihaskell",
+   "file_extension": ".hs",
+   "name": "haskell",
+   "pygments_lexer": "Haskell",
+   "version": "8.6.5"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 2
+}