Implement pig-latin in Elixir

elixir/pig-latin/.formatter.exs

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+# Used by "mix format"
+[
+ inputs: ["{mix,.formatter}.exs", "{config,lib,test}/**/*.{ex,exs}"]
+]

elixir/pig-latin/.gitignore

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+# The directory Mix will write compiled artifacts to.
+/_build/
+
+# If you run "mix test --cover", coverage assets end up here.
+/cover/
+
+# The directory Mix downloads your dependencies sources to.
+/deps/
+
+# Where third-party dependencies like ExDoc output generated docs.
+/doc/
+
+# Ignore .fetch files in case you like to edit your project deps locally.
+/.fetch
+
+# If the VM crashes, it generates a dump, let's ignore it too.
+erl_crash.dump
+
+# Also ignore archive artifacts (built via "mix archive.build").
+*.ez
+
+# Ignore package tarball (built via "mix hex.build").
+pig_latin-*.tar
+

elixir/pig-latin/HELP.md

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+# Help
+
+## Running the tests
+
+From the terminal, change to the base directory of the exercise then execute the tests with:
+
+```bash
+$ mix test
+```
+
+This will execute the test file found in the `test` subfolder -- a file ending in `_test.exs`
+
+Documentation:
+
+* [`mix test` - Elixir's test execution tool](https://hexdocs.pm/mix/Mix.Tasks.Test.html)
+* [`ExUnit` - Elixir's unit test library](https://hexdocs.pm/ex_unit/ExUnit.html)
+
+## Pending tests
+
+In test suites of practice exercises, all but the first test have been tagged to be skipped.
+
+Once you get a test passing, you can unskip the next one by commenting out the relevant `@tag :pending` with a `#` symbol.
+
+For example:
+
+```elixir
+# @tag :pending
+test "shouting" do
+ assert Bob.hey("WATCH OUT!") == "Whoa, chill out!"
+end
+```
+
+If you wish to run all tests at once, you can include all skipped test by using the `--include` flag on the `mix test` command:
+
+```bash
+$ mix test --include pending
+```
+
+Or, you can enable all the tests by commenting out the `ExUnit.configure` line in the file `test/test_helper.exs`.
+
+```elixir
+# ExUnit.configure(exclude: :pending, trace: true)
+```
+
+## Useful `mix test` options
+
+* `test/<FILE>.exs:LINENUM` - runs only a single test, the test from `<FILE>.exs` whose definition is on line `LINENUM`
+* `--failed` - runs only tests that failed the last time they ran
+* `--max-failures` - the suite stops evaluating tests when this number of test failures
+is reached
+* `--seed 0` - disables randomization so the tests in a single file will always be ran
+in the same order they were defined in
+
+## Submitting your solution
+
+You can submit your solution using the `exercism submit lib/pig_latin.ex` command.
+This command will upload your solution to the Exercism website and print the solution page's URL.
+
+It's possible to submit an incomplete solution which allows you to:
+
+- See how others have completed the exercise
+- Request help from a mentor
+
+## Need to get help?
+
+If you'd like help solving the exercise, check the following pages:
+
+- The [Elixir track's documentation](https://exercism.org/docs/tracks/elixir)
+- The [Elixir track's programming category on the forum](https://forum.exercism.org/c/programming/elixir)
+- [Exercism's programming category on the forum](https://forum.exercism.org/c/programming/5)
+- The [Frequently Asked Questions](https://exercism.org/docs/using/faqs)
+
+Should those resources not suffice, you could submit your (incomplete) solution to request mentoring.
+
+If you're stuck on something, it may help to look at some of the [available resources](https://exercism.org/docs/tracks/elixir/resources) out there where answers might be found.

elixir/pig-latin/README.md

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+# Pig Latin
+
+Welcome to Pig Latin on Exercism's Elixir Track.
+If you need help running the tests or submitting your code, check out `HELP.md`.
+
+## Instructions
+
+Implement a program that translates from English to Pig Latin.
+
+Pig Latin is a made-up children's language that's intended to be confusing.
+It obeys a few simple rules (below), but when it's spoken quickly it's really difficult for non-children (and non-native speakers) to understand.
+
+- **Rule 1**: If a word begins with a vowel sound, add an "ay" sound to the end of the word.
+ Please note that "xr" and "yt" at the beginning of a word make vowel sounds (e.g. "xray" -> "xrayay", "yttria" -> "yttriaay").
+- **Rule 2**: If a word begins with a consonant sound, move it to the end of the word and then add an "ay" sound to the end of the word.
+ Consonant sounds can be made up of multiple consonants, such as the "ch" in "chair" or "st" in "stand" (e.g. "chair" -> "airchay").
+- **Rule 3**: If a word starts with a consonant sound followed by "qu", move it to the end of the word, and then add an "ay" sound to the end of the word (e.g. "square" -> "aresquay").
+- **Rule 4**: If a word contains a "y" after a consonant cluster or as the second letter in a two letter word it makes a vowel sound (e.g. "rhythm" -> "ythmrhay", "my" -> "ymay").
+
+There are a few more rules for edge cases, and there are regional variants too.
+Check the tests for all the details.
+
+Read more about [Pig Latin on Wikipedia][pig-latin].
+
+[pig-latin]: https://en.wikipedia.org/wiki/Pig_latin
+
+## Source
+
+### Created by
+
+- @DoggettCK
+
+### Contributed to by
+
+- @alarregoity
+- @angelikatyborska
+- @Cohen-Carlisle
+- @devonestes
+- @moxley
+- @neenjaw
+- @sotojuan
+
+### Based on
+
+The Pig Latin exercise at Test First Teaching by Ultrasaurus - https://github.com/ultrasaurus/test-first-teaching/blob/master/learn_ruby/pig_latin/

elixir/pig-latin/lib/pig_latin.ex

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+defmodule PigLatin do
+ @doc """
+ Given a `phrase`, translate it a word at a time to Pig Latin.
+ """
+ @spec translate(phrase :: String.t()) :: String.t()
+ def translate(phrase) do
+ phrase
+ |> String.split(" ")
+ |> Enum.map(&translate_word/1)
+ |> Enum.join(" ")
+ end
+
+ defp translate_word(phrase) do
+ cond do
+ String.starts_with?(phrase, ["a", "e", "i", "o", "u"]) ->
+ phrase <> "ay"
+
+ String.starts_with?(phrase, "qu") ->
+ String.slice(phrase, 2..String.length(phrase)) <> "quay"
+
+ String.match?(phrase, ~r/^.qu/) ->
+ String.slice(phrase, 3..String.length(phrase)) <> String.first(phrase) <> "quay"
+
+ String.match?(phrase, ~r/^[xy][^aeiou].+$/) ->
+ phrase <> "ay"
+
+ String.match?(phrase, ~r/^\wy$/) ->
+ "y" <> String.first(phrase) <> "ay"
+
+ String.match?(phrase, ~r/^[^aeiou]+y/) ->
+ first_consonants =
+ phrase
+ |> String.codepoints()
+ |> Enum.take_while(fn char ->
+ char != "y"
+ end)
+ |> to_string()
+
+ String.slice(phrase, String.length(first_consonants)..String.length(phrase)) <>
+ first_consonants <> "ay"
+
+ true ->
+ first_consonants =
+ phrase
+ |> String.codepoints()
+ |> Enum.take_while(fn char ->
+ !(char in ["a", "e", "i", "o", "u"])
+ end)
+ |> to_string()
+
+ String.slice(phrase, String.length(first_consonants)..String.length(phrase)) <>
+ first_consonants <> "ay"
+ end
+ end
+end

elixir/pig-latin/mix.exs

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+defmodule PigLatin.MixProject do
+ use Mix.Project
+
+ def project do
+ [
+ app: :pig_latin,
+ version: "0.1.0",
+ # elixir: "~> 1.8",
+ start_permanent: Mix.env() == :prod,
+ deps: deps()
+ ]
+ end
+
+ # Run "mix help compile.app" to learn about applications.
+ def application do
+ [
+ extra_applications: [:logger]
+ ]
+ end
+
+ # Run "mix help deps" to learn about dependencies.
+ defp deps do
+ [
+ # {:dep_from_hexpm, "~> 0.3.0"},
+ # {:dep_from_git, git: "https://github.com/elixir-lang/my_dep.git", tag: "0.1.0"}
+ ]
+ end
+end

elixir/pig-latin/test/pig_latin_test.exs

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+defmodule PigLatinTest do
+ use ExUnit.Case
+
+ describe "ay is added to words that start with vowels" do
+ test "word beginning with a" do
+ assert PigLatin.translate("apple") == "appleay"
+ end
+
+ test "word beginning with e" do
+ assert PigLatin.translate("ear") == "earay"
+ end
+
+ test "word beginning with i" do
+ assert PigLatin.translate("igloo") == "iglooay"
+ end
+
+ test "word beginning with o" do
+ assert PigLatin.translate("object") == "objectay"
+ end
+
+ test "word beginning with u" do
+ assert PigLatin.translate("under") == "underay"
+ end
+
+ test "word beginning with a vowel and followed by a qu" do
+ assert PigLatin.translate("equal") == "equalay"
+ end
+ end
+
+ describe "first consonant letters and ay are moved to the end of words that start with consonants" do
+ test "word beginning with p" do
+ assert PigLatin.translate("pig") == "igpay"
+ end
+
+ test "word beginning with k" do
+ assert PigLatin.translate("koala") == "oalakay"
+ end
+
+ test "word beginning with x" do
+ assert PigLatin.translate("xenon") == "enonxay"
+ end
+
+ test "word beginning with q without a following u" do
+ assert PigLatin.translate("qat") == "atqay"
+ end
+
+ test "word beginning with two consonants" do
+ assert PigLatin.translate("pleasure") == "easureplay"
+ end
+
+ test "word beginning with three consonants" do
+ assert PigLatin.translate("stringify") == "ingifystray"
+ end
+
+ test "word beginning with a series of consonants : aliens speak Pig Latin too" do
+ assert PigLatin.translate("zkrrkrkrkrzzzkewk") == "ewkzkrrkrkrkrzzzkay"
+ end
+ end
+
+ describe "consecutive consonants are treated like a single consonant" do
+ test "word beginning with ch" do
+ assert PigLatin.translate("chair") == "airchay"
+ end
+
+ test "word beginning with qu" do
+ assert PigLatin.translate("queen") == "eenquay"
+ end
+
+ test "word beginning with qu and a preceding consonant" do
+ assert PigLatin.translate("square") == "aresquay"
+ end
+
+ test "word beginning with th" do
+ assert PigLatin.translate("therapy") == "erapythay"
+ end
+
+ test "word beginning with thr" do
+ assert PigLatin.translate("thrush") == "ushthray"
+ end
+
+ test "word beginning with sch" do
+ assert PigLatin.translate("school") == "oolschay"
+ end
+ end
+
+ describe "'x' and 'y', when followed by a consonant, are treated like a vowel" do
+ test "word beginning with y, followed by a consonant" do
+ assert PigLatin.translate("yttria") == "yttriaay"
+ end
+
+ test "word beginning with y, followed by another consonant" do
+ assert PigLatin.translate("yddria") == "yddriaay"
+ end
+
+ test "word beginning with xr" do
+ assert PigLatin.translate("xray") == "xrayay"
+ end
+
+ test "word beginning with xb" do
+ assert PigLatin.translate("xbot") == "xbotay"
+ end
+ end
+
+ describe "position of y in a word determines if it is a consonant or a vowel" do
+ test "y is treated like a consonant at the beginning of a word" do
+ assert PigLatin.translate("yellow") == "ellowyay"
+ end
+
+ test "y is treated like a vowel at the end of a consonant cluster" do
+ assert PigLatin.translate("rhythm") == "ythmrhay"
+ end
+
+ test "y as second letter in two letter word" do
+ assert PigLatin.translate("my") == "ymay"
+ end
+ end
+
+ describe "phrases are translated" do
+ test "a whole phrase" do
+ assert PigLatin.translate("quick fast run") == "ickquay astfay unray"
+ end
+ end
+end

elixir/pig-latin/test/test_helper.exs

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+ExUnit.start()
+ExUnit.configure(exclude: :pending, trace: true)