Add proverb exercise (#517)

* Add proverb exercise

* Apply suggestions from code review

---------

Co-authored-by: Ryan Hartlage <[email protected]>

Author: keiravillekode

config.json

@@ -536,6 +536,14 @@
           "strings"
         ]
       },
+      {
+        "slug": "proverb",
+        "name": "Proverb",
+        "uuid": "fe8aca38-4d7d-4a22-bae2-8e16e60c972e",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 3
+      },
       {
         "slug": "pythagorean-triplet",
         "name": "Pythagorean Triplet",

exercises/practice/proverb/.busted

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

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": [
+    "keiravillekode"
+  ],
+  "files": {
+    "solution": [
+      "proverb.lua"
+    ],
+    "test": [
+      "proverb_spec.lua"
+    ],
+    "example": [
+      ".meta/example.lua"
+    ]
+  },
+  "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.lua

@@ -0,0 +1,19 @@
+local Proverb = {}
+
+function Proverb.recite(strings)
+  if #strings == 0 then
+    return ''
+  end
+
+  local lines = {}
+  local template = "For want of a %s the %s was lost.\n"
+  for index = 2, #strings do
+    table.insert(lines, template:format(strings[index - 1], strings[index]))
+  end
+
+  template = "And all for the want of a %s.\n"
+  table.insert(lines, template:format(strings[1]))
+  return table.concat(lines)
+end
+
+return 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.lua

@@ -0,0 +1,6 @@
+local Proverb = {}
+
+function Proverb.recite(strings)
+end
+
+return Proverb

exercises/practice/proverb/proverb_spec.lua

@@ -0,0 +1,56 @@
+local Proverb = require 'proverb'
+
+describe('proverb', function()
+  it('zero pieces', function()
+    local strings = {}
+    local expected = table.concat({})
+    assert.equal(expected, Proverb.recite(strings))
+  end)
+
+  it('one piece', function()
+    local strings = { 'nail' }
+    local expected = table.concat({ "And all for the want of a nail.\n" })
+    assert.equal(expected, Proverb.recite(strings))
+  end)
+
+  it('two pieces', function()
+    local strings = { 'nail', 'shoe' }
+    local expected = table.concat({ "For want of a nail the shoe was lost.\n", "And all for the want of a nail.\n" })
+    assert.equal(expected, Proverb.recite(strings))
+  end)
+
+  it('three pieces', function()
+    local strings = { 'nail', 'shoe', 'horse' }
+    local expected = table.concat({
+      "For want of a nail the shoe was lost.\n",
+      "For want of a shoe the horse was lost.\n",
+      "And all for the want of a nail.\n"
+    })
+    assert.equal(expected, Proverb.recite(strings))
+  end)
+
+  it('full proverb', function()
+    local strings = { 'nail', 'shoe', 'horse', 'rider', 'message', 'battle', 'kingdom' }
+    local expected = table.concat({
+      "For want of a nail the shoe was lost.\n",
+      "For want of a shoe the horse was lost.\n",
+      "For want of a horse the rider was lost.\n",
+      "For want of a rider the message was lost.\n",
+      "For want of a message the battle was lost.\n",
+      "For want of a battle the kingdom was lost.\n",
+      "And all for the want of a nail.\n"
+    })
+    assert.equal(expected, Proverb.recite(strings))
+  end)
+
+  it('four pieces modernized', function()
+    local strings = { 'pin', 'gun', 'soldier', 'battle' }
+    local expected = table.concat({
+      "For want of a pin the gun was lost.\n",
+      "For want of a gun the soldier was lost.\n",
+      "For want of a soldier the battle was lost.\n",
+      "And all for the want of a pin.\n"
+    })
+    assert.equal(expected, Proverb.recite(strings))
+  end)
+end)