Add pig-latin exercise (exercism#217)

* Add pig-latin exercise

* rule 1 with single letter words

config.json

@@ -679,6 +679,14 @@
         "prerequisites": [],
         "difficulty": 4
       },
+      {
+        "slug": "pig-latin",
+        "name": "Pig Latin",
+        "uuid": "351ee590-6869-460e-815e-ae8644c8ed9e",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 4
+      },
       {
         "slug": "gigasecond",
         "name": "Gigasecond",

exercises/practice/pig-latin/.docs/instructions.md

@@ -0,0 +1,46 @@
+# Instructions
+
+Your task is to translate text from English to Pig Latin.
+The translation is defined using four rules, which look at the pattern of vowels and consonants at the beginning of a word.
+These rules look at each word's use of vowels and consonants:
+
+- vowels: the letters `a`, `e`, `i`, `o`, and `u`
+- consonants: the other 21 letters of the English alphabet
+
+## Rule 1
+
+If a word begins with a vowel, or starts with `"xr"` or `"yt"`, add an `"ay"` sound to the end of the word.
+
+For example:
+
+- `"apple"` -> `"appleay"` (starts with vowel)
+- `"xray"` -> `"xrayay"` (starts with `"xr"`)
+- `"yttria"` -> `"yttriaay"` (starts with `"yt"`)
+
+## Rule 2
+
+If a word begins with a one or more consonants, first move those consonants to the end of the word and then add an `"ay"` sound to the end of the word.
+
+For example:
+
+- `"pig"` -> `"igp"` -> `"igpay"` (starts with single consonant)
+- `"chair"` -> `"airch"` -> `"airchay"` (starts with multiple consonants)
+- `"thrush"` -> `"ushthr"` -> `"ushthray"` (starts with multiple consonants)
+
+## Rule 3
+
+If a word starts with zero or more consonants followed by `"qu"`, first move those consonants (if any) and the `"qu"` part to the end of the word, and then add an `"ay"` sound to the end of the word.
+
+For example:
+
+- `"quick"` -> `"ickqu"` -> `"ay"` (starts with `"qu"`, no preceding consonants)
+- `"square"` -> `"aresqu"` -> `"aresquay"` (starts with one consonant followed by `"qu`")
+
+## Rule 4
+
+If a word starts with one or more consonants followed by `"y"`, first move the consonants preceding the `"y"`to the end of the word, and then add an `"ay"` sound to the end of the word.
+
+Some examples:
+
+- `"my"` -> `"ym"` -> `"ymay"` (starts with single consonant followed by `"y"`)
+- `"rhythm"` -> `"ythmrh"` -> `"ythmrhay"` (starts with multiple consonants followed by `"y"`)

exercises/practice/pig-latin/.docs/introduction.md

@@ -0,0 +1,8 @@
+# Introduction
+
+Your parents have challenged you and your sibling to a game of two-on-two basketball.
+Confident they'll win, they let you score the first couple of points, but then start taking over the game.
+Needing a little boost, you start speaking in [Pig Latin][pig-latin], which is a made-up children's language that's difficult for non-children to understand.
+This will give you the edge to prevail over your parents!
+
+[pig-latin]: https://en.wikipedia.org/wiki/Pig_latin

exercises/practice/pig-latin/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "keiravillekode"
+  ],
+  "files": {
+    "solution": [
+      "pig-latin.v"
+    ],
+    "test": [
+      "run_test.v"
+    ],
+    "example": [
+      ".meta/example.v"
+    ]
+  },
+  "blurb": "Implement a program that translates from English to Pig Latin.",
+  "source": "The Pig Latin exercise at Test First Teaching by Ultrasaurus",
+  "source_url": "https://github.com/ultrasaurus/test-first-teaching/blob/master/learn_ruby/pig_latin/"
+}

exercises/practice/pig-latin/.meta/example.v

@@ -0,0 +1,67 @@
+module main
+
+import strings
+
+fn translate(phrase string) string {
+	vowel := [
+		true, // a
+		false,
+		false,
+		false,
+		true, // e
+		false,
+		false,
+		false,
+		true, // i
+		false,
+		false,
+		false,
+		false,
+		false,
+		true, // o
+		false,
+		false,
+		false,
+		false,
+		false,
+		true, // u
+		false,
+		false,
+		false,
+		true, // y
+		false,
+	]
+
+	words := phrase.split(' ')
+	mut builder := strings.new_builder(phrase.len + 2 * words.len)
+	for word in words {
+		mut index := 0
+		rule1 := if vowel[word[0] - `a`] {
+			word[0] != `y` || (word.len > 1 && word[0..2] == 'yt')
+		} else {
+			word.len > 1 && word[0..2] == 'xr'
+		}
+
+		if !rule1 {
+			index++
+
+			// Rules 2 and 4: `y` is treated like a vowel.
+			for index < word.len && !vowel[word[index] - `a`] {
+				index++
+			}
+
+			// Rule 3
+			if index < word.len && word[(index - 1)..(index + 1)] == 'qu' {
+				index++
+			}
+		}
+		if builder.len != 0 {
+			builder.write_string(' ')
+		}
+		builder.write_string(word[index..])
+		builder.write_string(word[..index])
+		builder.write_string('ay')
+	}
+
+	return builder.str()
+}

exercises/practice/pig-latin/.meta/tests.toml

@@ -0,0 +1,69 @@
+# This is an auto-generated file. Regular comments will be removed when this
+# file is regenerated. Regenerating will not touch any manually added keys,
+# so comments can be added in a "comment" key.
+
+[11567f84-e8c6-4918-aedb-435f0b73db57]
+description = "ay is added to words that start with vowels -> word beginning with a"
+
+[f623f581-bc59-4f45-9032-90c3ca9d2d90]
+description = "ay is added to words that start with vowels -> word beginning with e"
+
+[7dcb08b3-23a6-4e8a-b9aa-d4e859450d58]
+description = "ay is added to words that start with vowels -> word beginning with i"
+
+[0e5c3bff-266d-41c8-909f-364e4d16e09c]
+description = "ay is added to words that start with vowels -> word beginning with o"
+
+[614ba363-ca3c-4e96-ab09-c7320799723c]
+description = "ay is added to words that start with vowels -> word beginning with u"
+
+[bf2538c6-69eb-4fa7-a494-5a3fec911326]
+description = "ay is added to words that start with vowels -> word beginning with a vowel and followed by a qu"
+
+[e5be8a01-2d8a-45eb-abb4-3fcc9582a303]
+description = "first letter and ay are moved to the end of words that start with consonants -> word beginning with p"
+
+[d36d1e13-a7ed-464d-a282-8820cb2261ce]
+description = "first letter and ay are moved to the end of words that start with consonants -> word beginning with k"
+
+[d838b56f-0a89-4c90-b326-f16ff4e1dddc]
+description = "first letter and ay are moved to the end of words that start with consonants -> word beginning with x"
+
+[bce94a7a-a94e-4e2b-80f4-b2bb02e40f71]
+description = "first letter and ay are moved to the end of words that start with consonants -> word beginning with q without a following u"
+
+[c01e049a-e3e2-451c-bf8e-e2abb7e438b8]
+description = "some letter clusters are treated like a single consonant -> word beginning with ch"
+
+[9ba1669e-c43f-4b93-837a-cfc731fd1425]
+description = "some letter clusters are treated like a single consonant -> word beginning with qu"
+
+[92e82277-d5e4-43d7-8dd3-3a3b316c41f7]
+description = "some letter clusters are treated like a single consonant -> word beginning with qu and a preceding consonant"
+
+[79ae4248-3499-4d5b-af46-5cb05fa073ac]
+description = "some letter clusters are treated like a single consonant -> word beginning with th"
+
+[e0b3ae65-f508-4de3-8999-19c2f8e243e1]
+description = "some letter clusters are treated like a single consonant -> word beginning with thr"
+
+[20bc19f9-5a35-4341-9d69-1627d6ee6b43]
+description = "some letter clusters are treated like a single consonant -> word beginning with sch"
+
+[54b796cb-613d-4509-8c82-8fbf8fc0af9e]
+description = "some letter clusters are treated like a single vowel -> word beginning with yt"
+
+[8c37c5e1-872e-4630-ba6e-d20a959b67f6]
+description = "some letter clusters are treated like a single vowel -> word beginning with xr"
+
+[a4a36d33-96f3-422c-a233-d4021460ff00]
+description = "position of y in a word determines if it is a consonant or a vowel -> y is treated like a consonant at the beginning of a word"
+
+[adc90017-1a12-4100-b595-e346105042c7]
+description = "position of y in a word determines if it is a consonant or a vowel -> y is treated like a vowel at the end of a consonant cluster"
+
+[29b4ca3d-efe5-4a95-9a54-8467f2e5e59a]
+description = "position of y in a word determines if it is a consonant or a vowel -> y as second letter in two letter word"
+
+[44616581-5ce3-4a81-82d0-40c7ab13d2cf]
+description = "phrases are translated -> a whole phrase"

exercises/practice/pig-latin/pig-latin.v

@@ -0,0 +1,4 @@
+module main
+
+fn translate(phrase string) string {
+}

exercises/practice/pig-latin/run_test.v

@@ -0,0 +1,89 @@
+module main
+
+fn test_ay_is_added_to_words_that_start_with_vowels__word_beginning_with_a() {
+	assert translate('apple') == 'appleay'
+}
+
+fn test_ay_is_added_to_words_that_start_with_vowels__word_beginning_with_e() {
+	assert translate('ear') == 'earay'
+}
+
+fn test_ay_is_added_to_words_that_start_with_vowels__word_beginning_with_i() {
+	assert translate('igloo') == 'iglooay'
+}
+
+fn test_ay_is_added_to_words_that_start_with_vowels__word_beginning_with_o() {
+	assert translate('object') == 'objectay'
+}
+
+fn test_ay_is_added_to_words_that_start_with_vowels__word_beginning_with_u() {
+	assert translate('under') == 'underay'
+}
+
+fn test_ay_is_added_to_words_that_start_with_vowels__word_beginning_with_a_vowel_and_followed_by_a_qu() {
+	assert translate('equal') == 'equalay'
+}
+
+fn test_first_letter_and_ay_are_moved_to_the_end_of_words_that_start_with_consonants__word_beginning_with_p() {
+	assert translate('pig') == 'igpay'
+}
+
+fn test_first_letter_and_ay_are_moved_to_the_end_of_words_that_start_with_consonants__word_beginning_with_k() {
+	assert translate('koala') == 'oalakay'
+}
+
+fn test_first_letter_and_ay_are_moved_to_the_end_of_words_that_start_with_consonants__word_beginning_with_x() {
+	assert translate('xenon') == 'enonxay'
+}
+
+fn test_first_letter_and_ay_are_moved_to_the_end_of_words_that_start_with_consonants__word_beginning_with_q_without_a_following_u() {
+	assert translate('qat') == 'atqay'
+}
+
+fn test_some_letter_clusters_are_treated_like_a_single_consonant__word_beginning_with_ch() {
+	assert translate('chair') == 'airchay'
+}
+
+fn test_some_letter_clusters_are_treated_like_a_single_consonant__word_beginning_with_qu() {
+	assert translate('queen') == 'eenquay'
+}
+
+fn test_some_letter_clusters_are_treated_like_a_single_consonant__word_beginning_with_qu_and_a_preceding_consonant() {
+	assert translate('square') == 'aresquay'
+}
+
+fn test_some_letter_clusters_are_treated_like_a_single_consonant__word_beginning_with_th() {
+	assert translate('therapy') == 'erapythay'
+}
+
+fn test_some_letter_clusters_are_treated_like_a_single_consonant__word_beginning_with_thr() {
+	assert translate('thrush') == 'ushthray'
+}
+
+fn test_some_letter_clusters_are_treated_like_a_single_consonant__word_beginning_with_sch() {
+	assert translate('school') == 'oolschay'
+}
+
+fn test_some_letter_clusters_are_treated_like_a_single_vowel__word_beginning_with_yt() {
+	assert translate('yttria') == 'yttriaay'
+}
+
+fn test_some_letter_clusters_are_treated_like_a_single_vowel__word_beginning_with_xr() {
+	assert translate('xray') == 'xrayay'
+}
+
+fn test_position_of_y_in_a_word_determines_if_it_is_a_consonant_or_a_vowel__y_is_treated_like_a_consonant_at_the_beginning_of_a_word() {
+	assert translate('yellow') == 'ellowyay'
+}
+
+fn test_position_of_y_in_a_word_determines_if_it_is_a_consonant_or_a_vowel__y_is_treated_like_a_vowel_at_the_end_of_a_consonant_cluster() {
+	assert translate('rhythm') == 'ythmrhay'
+}
+
+fn test_position_of_y_in_a_word_determines_if_it_is_a_consonant_or_a_vowel__y_as_second_letter_in_two_letter_word() {
+	assert translate('my') == 'ymay'
+}
+
+fn test_phrases_are_translated__a_whole_phrase() {
+	assert translate('quick fast run') == 'ickquay astfay unray'
+}