Add ETL (#332)

Author: BNAndras

config.json

@@ -168,6 +168,14 @@
         "prerequisites": [],
         "difficulty": 2
       },
+      {
+        "slug": "etl",
+        "name": "ETL",
+        "uuid": "2a1c165e-3ee8-47a4-b19d-7e44c79458f0",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 2
+      },
       {
         "slug": "gigasecond",
         "name": "Gigasecond",

exercises/practice/etl/.docs/instructions.md

@@ -0,0 +1,27 @@
+# Instructions
+
+Your task is to change the data format of letters and their point values in the game.
+
+Currently, letters are stored in groups based on their score, in a one-to-many mapping.
+
+- 1 point: "A", "E", "I", "O", "U", "L", "N", "R", "S", "T",
+- 2 points: "D", "G",
+- 3 points: "B", "C", "M", "P",
+- 4 points: "F", "H", "V", "W", "Y",
+- 5 points: "K",
+- 8 points: "J", "X",
+- 10 points: "Q", "Z",
+
+This needs to be changed to store each individual letter with its score in a one-to-one mapping.
+
+- "a" is worth 1 point.
+- "b" is worth 3 points.
+- "c" is worth 3 points.
+- "d" is worth 2 points.
+- etc.
+
+As part of this change, the team has also decided to change the letters to be lower-case rather than upper-case.
+
+~~~~exercism/note
+If you want to look at how the data was previously structured and how it needs to change, take a look at the examples in the test suite.
+~~~~

exercises/practice/etl/.docs/introduction.md

@@ -0,0 +1,16 @@
+# Introduction
+
+You work for a company that makes an online multiplayer game called Lexiconia.
+
+To play the game, each player is given 13 letters, which they must rearrange to create words.
+Different letters have different point values, since it's easier to create words with some letters than others.
+
+The game was originally launched in English, but it is very popular, and now the company wants to expand to other languages as well.
+
+Different languages need to support different point values for letters.
+The point values are determined by how often letters are used, compared to other letters in that language.
+
+For example, the letter 'C' is quite common in English, and is only worth 3 points.
+But in Norwegian it's a very rare letter, and is worth 10 points.
+
+To make it easier to add new languages, your team needs to change the way letters and their point values are stored in the game.

exercises/practice/etl/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "BNAndras"
+  ],
+  "files": {
+    "solution": [
+      "etl.coffee"
+    ],
+    "test": [
+      "etl.spec.coffee"
+    ],
+    "example": [
+      ".meta/example.coffee"
+    ]
+  },
+  "blurb": "Change the data format for scoring a game to more easily add other languages.",
+  "source": "Based on an exercise by the JumpstartLab team for students at The Turing School of Software and Design.",
+  "source_url": "https://turing.edu"
+}

exercises/practice/etl/.meta/example.coffee

@@ -0,0 +1,9 @@
+class Etl
+  @transform: (legacy) ->
+    results = {}
+    for score, letters of legacy
+      for letter in letters
+        results[letter.toLowerCase()] = +score
+    results
+
+module.exports = Etl

exercises/practice/etl/.meta/tests.toml

@@ -0,0 +1,22 @@
+# This is an auto-generated file.
+#
+# Regenerating this file via `configlet sync` will:
+# - Recreate every `description` key/value pair
+# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
+# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
+# - Preserve any other key/value pair
+#
+# As user-added comments (using the # character) will be removed when this file
+# is regenerated, comments can be added via a `comment` key.
+
+[78a7a9f9-4490-4a47-8ee9-5a38bb47d28f]
+description = "single letter"
+
+[60dbd000-451d-44c7-bdbb-97c73ac1f497]
+description = "single score with multiple letters"
+
+[f5c5de0c-301f-4fdd-a0e5-df97d4214f54]
+description = "multiple scores with multiple letters"
+
+[5db8ea89-ecb4-4dcd-902f-2b418cc87b9d]
+description = "multiple scores with differing numbers of letters"

exercises/practice/etl/etl.coffee

@@ -0,0 +1,4 @@
+class Etl
+  @transform: (legacy) ->
+
+module.exports = Etl

exercises/practice/etl/etl.spec.coffee

@@ -0,0 +1,31 @@
+Etl = require './etl'
+
+describe "ETL", ->
+  it 'single letter', ->
+    result = Etl.transform { 1: ['A'] }
+    expect(result).toEqual { 'a': 1 }
+
+  xit 'single score with multiple letters', ->
+    result = Etl.transform { 1: ['A', 'E', 'I', 'O', 'U'] }
+    expect(result).toEqual { 'a': 1, 'e': 1, 'i': 1, 'o': 1, 'u': 1 }
+
+  xit 'multiple scores with multiple letters', ->
+    result = Etl.transform { 1: ['A', 'E'], 2: ['D', 'G'] }
+    expect(result).toEqual { 'a': 1, 'd': 2, 'e': 1, 'g': 2 }
+
+  xit 'multiple scores with differing numbers of letters', ->
+    result = Etl.transform {
+      1: ['A', 'E', 'I', 'O', 'U', 'L', 'N', 'R', 'S', 'T']
+      2: ['D', 'G']
+      3: ['B', 'C', 'M', 'P']
+      4: ['F', 'H', 'V', 'W', 'Y']
+      5: ['K']
+      8: ['J', 'X']
+      10: ['Q', 'Z']
+    }
+    expect(result).toEqual {
+      'a': 1, 'b': 3, 'c': 3, 'd': 2, 'e': 1, 'f': 4, 'g': 2, 'h': 4,
+      'i': 1, 'j': 8, 'k': 5, 'l': 1, 'm': 3, 'n': 1, 'o': 1, 'p': 3,
+      'q': 10, 'r': 1, 's': 1, 't': 1, 'u': 1, 'v': 4, 'w': 4, 'x': 8,
+      'y': 4, 'z': 10
+    }