Add etl (#89)

Author: BNAndras

config.json

@@ -90,6 +90,14 @@
         "prerequisites": [],
         "difficulty": 2
       },
+      {
+        "slug": "etl",
+        "name": "ETL",
+        "uuid": "2c772f04-f65d-48f8-a19b-efaa84a5226d",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 2
+      },
       {
         "slug": "hamming",
         "name": "Hamming",

exercises/practice/etl/.busted

@@ -0,0 +1,5 @@
+return {
+  default = {
+    ROOT = { '.' }
+  }
+}

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.moon"
+    ],
+    "test": [
+      "etl_spec.moon"
+    ],
+    "example": [
+      ".meta/example.moon"
+    ]
+  },
+  "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://www.turing.edu/"
+}

exercises/practice/etl/.meta/example.moon

@@ -0,0 +1,8 @@
+{
+  transform: (legacy) ->
+    result = {}
+    for score, letters in pairs legacy
+      for letter in *letters
+        result[letter\lower!] = tonumber(score)
+    result
+}

exercises/practice/etl/.meta/spec_generator.moon

@@ -0,0 +1,23 @@
+string_list = (list) -> "{#{table.concat [quote(v) for v in *list], ', '}}"
+
+{
+  module_name: 'Etl',
+
+  generate_test: (case, level) ->
+    lines = {}
+
+    table.insert lines, "legacy = {"
+    for k, v in pairs case.input.legacy
+      table.insert lines, "  #{quote k}: #{string_list v}"
+    table.insert lines, "}"
+
+    table.insert lines, "expected = {"
+    for k, v in pairs case.expected
+      table.insert lines, "  #{quote k}: #{v}"
+    table.insert lines, "}"
+
+    table.insert lines, "result = Etl.#{case.property} legacy"
+    table.insert lines, "assert.are.same expected, result"
+
+    table.concat [indent line, level for line in *lines], '\n'
+}

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.moon

@@ -0,0 +1,4 @@
+{
+  transform: (legacy) ->
+    error 'Implement me!'
+}

exercises/practice/etl/etl_spec.moon

@@ -0,0 +1,81 @@
+Etl = require 'etl'
+
+describe 'etl', ->
+  it 'single letter', ->
+    legacy = {
+      '1': {'A'}
+    }
+    expected = {
+      'a': 1
+    }
+    result = Etl.transform legacy
+    assert.are.same expected, result
+
+  pending 'single score with multiple letters', ->
+    legacy = {
+      '1': {'A', 'E', 'I', 'O', 'U'}
+    }
+    expected = {
+      'a': 1
+      'e': 1
+      'u': 1
+      'o': 1
+      'i': 1
+    }
+    result = Etl.transform legacy
+    assert.are.same expected, result
+
+  pending 'multiple scores with multiple letters', ->
+    legacy = {
+      '1': {'A', 'E'}
+      '2': {'D', 'G'}
+    }
+    expected = {
+      'a': 1
+      'd': 2
+      'g': 2
+      'e': 1
+    }
+    result = Etl.transform legacy
+    assert.are.same expected, result
+
+  pending 'multiple scores with differing numbers of letters', ->
+    legacy = {
+      '1': {'A', 'E', 'I', 'O', 'U', 'L', 'N', 'R', 'S', 'T'}
+      '8': {'J', 'X'}
+      '3': {'B', 'C', 'M', 'P'}
+      '2': {'D', 'G'}
+      '5': {'K'}
+      '4': {'F', 'H', 'V', 'W', 'Y'}
+      '10': {'Q', 'Z'}
+    }
+    expected = {
+      'a': 1
+      'c': 3
+      'b': 3
+      'e': 1
+      'd': 2
+      'g': 2
+      'f': 4
+      'i': 1
+      'h': 4
+      'k': 5
+      'j': 8
+      'm': 3
+      'l': 1
+      'o': 1
+      'n': 1
+      'q': 10
+      'p': 3
+      's': 1
+      'r': 1
+      'u': 1
+      't': 1
+      'w': 4
+      'v': 4
+      'y': 4
+      'x': 8
+      'z': 10
+    }
+    result = Etl.transform legacy
+    assert.are.same expected, result