Add proverb (#352)

Author: BNAndras

config.json

@@ -393,6 +393,14 @@
         "prerequisites": [],
         "difficulty": 2
       },
+      {
+        "slug": "proverb",
+        "name": "Proverb",
+        "uuid": "cad4e3b4-4fb4-4120-a0ae-b59796fd0dc7",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 2
+      },
       {
         "slug": "queen-attack",
         "name": "Queen Attack",

exercises/practice/proverb/.docs/instructions.md

@@ -0,0 +1,19 @@
+# Instructions
+
+For want of a horseshoe nail, a kingdom was lost, or so the saying goes.
+
+Given a list of inputs, generate the relevant proverb.
+For example, given the list `["nail", "shoe", "horse", "rider", "message", "battle", "kingdom"]`, you will output the full text of this proverbial rhyme:
+
+```text
+For want of a nail the shoe was lost.
+For want of a shoe the horse was lost.
+For want of a horse the rider was lost.
+For want of a rider the message was lost.
+For want of a message the battle was lost.
+For want of a battle the kingdom was lost.
+And all for the want of a nail.
+```
+
+Note that the list of inputs may vary; your solution should be able to handle lists of arbitrary length and content.
+No line of the output text should be a static, unchanging string; all should vary according to the input given.

exercises/practice/proverb/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "BNAndras"
+  ],
+  "files": {
+    "solution": [
+      "proverb.coffee"
+    ],
+    "test": [
+      "proverb.spec.coffee"
+    ],
+    "example": [
+      ".meta/example.coffee"
+    ]
+  },
+  "blurb": "For want of a horseshoe nail, a kingdom was lost, or so the saying goes. Output the full text of this proverbial rhyme.",
+  "source": "Wikipedia",
+  "source_url": "https://en.wikipedia.org/wiki/For_Want_of_a_Nail"
+}

exercises/practice/proverb/.meta/example.coffee

@@ -0,0 +1,11 @@
+class Proverb
+  @recite: (items) ->
+    if items.length == 0
+      return ""
+    proverb = ""
+    for i in [0...items.length - 1]
+      proverb += "For want of a #{items[i]} the #{items[i + 1]} was lost.\n"
+    proverb += "And all for the want of a #{items[0]}."
+    proverb
+
+module.exports = Proverb

exercises/practice/proverb/.meta/tests.toml

@@ -0,0 +1,28 @@
+# 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.
+
+[e974b73e-7851-484f-8d6d-92e07fe742fc]
+description = "zero pieces"
+
+[2fcd5f5e-8b82-4e74-b51d-df28a5e0faa4]
+description = "one piece"
+
+[d9d0a8a1-d933-46e2-aa94-eecf679f4b0e]
+description = "two pieces"
+
+[c95ef757-5e94-4f0d-a6cb-d2083f5e5a83]
+description = "three pieces"
+
+[433fb91c-35a2-4d41-aeab-4de1e82b2126]
+description = "full proverb"
+
+[c1eefa5a-e8d9-41c7-91d4-99fab6d6b9f7]
+description = "four pieces modernized"

exercises/practice/proverb/proverb.coffee

@@ -0,0 +1,4 @@
+class Proverb
+  @recite: (items) ->
+
+module.exports = Proverb

exercises/practice/proverb/proverb.spec.coffee

@@ -0,0 +1,60 @@
+Proverb = require './proverb'
+
+describe 'Proverb', ->
+  it 'zero pieces with a valid position', ->
+    items = []
+    expected = ''
+    expect(Proverb.recite items).toEqual expected
+
+  xit 'one piece', ->
+    items = ['nail']
+    expected = 'And all for the want of a nail.'
+    expect(Proverb.recite items).toEqual expected
+
+  xit 'two pieces', ->
+    items = ['nail', 'shoe']
+    expected = """
+      For want of a nail the shoe was lost.
+      And all for the want of a nail.
+    """
+    expect(Proverb.recite items).toEqual expected
+
+  xit 'three pieces', ->
+    items = ['nail', 'shoe', 'horse']
+    expected = """
+      For want of a nail the shoe was lost.
+      For want of a shoe the horse was lost.
+      And all for the want of a nail.
+    """
+    expect(Proverb.recite items).toEqual expected
+
+  xit 'full proverb', ->
+    items = [
+      'nail'
+      'shoe'
+      'horse'
+      'rider'
+      'message'
+      'battle'
+      'kingdom'
+    ]
+    expected = """
+      For want of a nail the shoe was lost.
+      For want of a shoe the horse was lost.
+      For want of a horse the rider was lost.
+      For want of a rider the message was lost.
+      For want of a message the battle was lost.
+      For want of a battle the kingdom was lost.
+      And all for the want of a nail.
+    """
+    expect(Proverb.recite items).toEqual expected
+
+  xit 'four pieces modernized', ->
+    items = ['pin', 'gun', 'soldier', 'battle']
+    expected = """
+      For want of a pin the gun was lost.
+      For want of a gun the soldier was lost.
+      For want of a soldier the battle was lost.
+      And all for the want of a pin.
+    """
+    expect(Proverb.recite items).toEqual expected