wine-cellar

elixir/wine-cellar/.exercism/config.json

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+{
+  "authors": [
+    "angelikatyborska"
+  ],
+  "contributors": [
+    "neenjaw"
+  ],
+  "files": {
+    "solution": [
+      "lib/wine_cellar.ex"
+    ],
+    "test": [
+      "test/wine_cellar_test.exs"
+    ],
+    "exemplar": [
+      ".meta/exemplar.ex"
+    ]
+  },
+  "language_versions": ">=1.10",
+  "blurb": "Learn about keyword lists by providing wine suggestions to the customers in your restaurant."
+}

elixir/wine-cellar/.exercism/metadata.json

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+{"track":"elixir","exercise":"wine-cellar","id":"de50f41fb5b4408e90f193a9d87670f6","url":"https://exercism.org/tracks/elixir/exercises/wine-cellar","handle":"negrienko","is_requester":true,"auto_approve":false}

elixir/wine-cellar/.formatter.exs

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

elixir/wine-cellar/.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").
+nil-*.tar
+

elixir/wine-cellar/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/wine_cellar.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/wine-cellar/HINTS.md

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+# Hints
+
+## General
+
+- Read about keyword lists in the official [Getting Started guide][getting-started-keyword-lists].
+- Read about keyword lists on [elixirschool.com][elixir-school-keyword-lists].
+- Take a look at the [documentation of the `Keyword` module][keyword].
+
+## 1. Explain wine colors
+
+- You need to write the information given in the table as a keyword list.
+- Take a look at some [examples][keyword-examples] of how to define a keyword list.
+
+## 2. Get all wines of a given color
+
+- There is a [built-in function][keyword-get-values] for getting the list of all values for a given key.
+
+## 3. Get all wines of a given color bottled in a given year
+
+- There is a [built-in function][keyword-get] for getting a single value for a given key.
+- You do not need to implement the filtering of bottles on your own. You just need to conditionally use the already-implemented `filter_by_year/2` function.
+
+## 4. Get all wines of a given color bottled in a given country
+
+- There is a [built-in function][keyword-get] for getting a single value for a given key.
+- You do not need to implement the filtering of bottles on your own. You just need to conditionally use the already-implemented `filter_by_country/2` function.
+
+[getting-started-keyword-lists]: https://elixir-lang.org/getting-started/keywords-and-maps.html#keyword-lists
+[elixir-school-keyword-lists]: https://elixirschool.com/en/lessons/basics/collections/#keyword-lists
+[keyword]: https://hexdocs.pm/elixir/Keyword.html
+[keyword-get-values]: https://hexdocs.pm/elixir/Keyword.html#get_values/2
+[keyword-get]: https://hexdocs.pm/elixir/Keyword.html#get/3
+[keyword-examples]: https://hexdocs.pm/elixir/Keyword.html#module-examples

elixir/wine-cellar/README.md

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+# Wine Cellar
+
+Welcome to Wine Cellar on Exercism's Elixir Track.
+If you need help running the tests or submitting your code, check out `HELP.md`.
+If you get stuck on the exercise, check out `HINTS.md`, but try and solve it without using those first :)
+
+## Introduction
+
+## Keyword Lists
+
+Keyword lists are a key-value data structure.
+
+```elixir
+[month: "April", year: 2018]
+```
+
+Keyword lists are lists of `{key, value}` [tuples][exercism-tuples], and can also be written as such, but the shorter syntax is more widely used.
+
+```elixir
+[month: "April"] == [{:month, "April"}]
+# => true
+```
+
+Keys in a keyword list must be [atoms][exercism-atoms], but the values can be anything. Each key can be used more than once. The key-value pairs in a keyword list are ordered.
+
+You can work with keyword lists using the same approaches as for lists, or you can use the `Keyword` module.
+
+[exercism-tuples]: https://exercism.org/tracks/elixir/concepts/tuples
+[exercism-atoms]: https://exercism.org/tracks/elixir/concepts/atoms
+
+## Instructions
+
+You are the manager of a fancy restaurant that has a sizable wine cellar. A lot of your customers are demanding wine enthusiasts. Finding the right bottle of wine for a particular customer is not an easy task.
+
+As a tech-savvy restaurant owner, you decided to speed up the wine selection process by writing an app that will let guests filter your wines by their preferences.
+
+## 1. Explain wine colors
+
+On the welcome screen of your app, you want to display a short explanation of each wine color.
+
+Implement the `WineCellar.explain_colors/0` function. It takes no arguments and returns a keyword list with wine colors as keys and explanations as values.
+
+| Color    | Explanation                                                                |
+| -------- | -------------------------------------------------------------------------- |
+| `:white` | Fermented without skin contact.                                            |
+| `:red`   | Fermented with skin contact using dark-colored grapes.                     |
+| `:rose`  | Fermented with some skin contact, but not enough to qualify as a red wine. |
+
+## 2. Get all wines of a given color
+
+A bottle of wine is represented as a 3-tuple of grape variety, year, and country of origin. The wines are stored by wine color in a keyword list.
+
+```elixir
+[
+  white: {"Chardonnay", 2015, "Italy"},
+  white: {"Pinot grigio", 2017, "Germany"},
+  red: {"Pinot noir", 2016, "France"},
+  rose: {"Dornfelder", 2018, "Germany"}
+]
+```
+
+Implement the `WineCellar.filter/3` function. It should take a keyword list of wines, a color atom and a keyword list of options, with a default value of `[]`. The function should return a list of wines of a given color.
+
+```elixir
+WineCellar.filter(
+  [
+    white: {"Chardonnay", 2015, "Italy"},
+    white: {"Pinot grigio", 2017, "Germany"},
+    red: {"Pinot noir", 2016, "France"},
+    rose: {"Dornfelder", 2018, "Germany"}
+  ],
+  :white
+)
+# => [
+#      {"Chardonnay", 2015, "Italy"},
+#      {"Pinot grigio", 2017, "Germany"}
+#    ]
+```
+
+## 3. Get all wines of a given color bottled in a given year
+
+Extend the `WineCellar.filter/3` function. When given a `:year` option, the function should return a list of wines of a given color from a given year.
+
+Use the already-implemented `WineCellar.filter_by_year/2` function. It takes a list of wines and a year as arguments and returns a list of wines from a given year.
+
+```elixir
+WineCellar.filter(
+  [
+    white: {"Chardonnay", 2015, "Italy"},
+    white: {"Pinot grigio", 2017, "Germany"},
+    red: {"Pinot noir", 2016, "France"},
+    rose: {"Dornfelder", 2018, "Germany"}
+  ],
+  :white,
+  year: 2015
+)
+# => [
+#      {"Chardonnay", 2015, "Italy"}
+#    ]
+```
+
+## 4. Get all wines of a given color bottled in a given country
+
+Extend the `WineCellar.filter/3` function. When given a `:country` option, the function should return a list of wines of a given color from a given country.
+
+Use the already-implemented `WineCellar.filter_by_country/2` function. It takes a list of wines and a country as arguments and returns a list of wines from a given country.
+
+Make sure that the function works when given both the `:year` and the `:country` option, in any order.
+
+```elixir
+WineCellar.filter(
+  [
+    white: {"Chardonnay", 2015, "Italy"},
+    white: {"Pinot grigio", 2017, "Germany"},
+    red: {"Pinot noir", 2016, "France"},
+    rose: {"Dornfelder", 2018, "Germany"}
+  ],
+  :white,
+  year: 2015,
+  country: "Germany"
+)
+# => []
+```
+
+## Source
+
+### Created by
+
+- @angelikatyborska
+
+### Contributed to by
+
+- @neenjaw

elixir/wine-cellar/lib/wine_cellar.ex

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+defmodule WineCellar do
+  @colors [
+    white: "Fermented without skin contact.",
+    red: "Fermented with skin contact using dark-colored grapes.",
+    rose: "Fermented with some skin contact, but not enough to qualify as a red wine."
+  ]
+
+  # @cellar [
+  #   white: {"Chardonnay", 2015, "Italy"},
+  #   white: {"Pinot grigio", 2017, "Germany"},
+  #   red: {"Pinot noir", 2016, "France"},
+  #   rose: {"Dornfelder", 2018, "Germany"}
+  # ]
+
+  def explain_colors(), do: @colors
+
+  def filter(cellar, color, opts \\ []) do
+    cellar
+    |> Keyword.get_values(color)
+    |> filter_by_year(opts[:year])
+    |> filter_by_country(opts[:country])
+  end
+
+  # The functions below do not need to be modified.
+
+  defp filter_by_year(wines, year)
+  defp filter_by_year(wines, nil), do: wines
+  defp filter_by_year([], _year), do: []
+
+  defp filter_by_year([{_, year, _} = wine | tail], year) do
+    [wine | filter_by_year(tail, year)]
+  end
+
+  defp filter_by_year([{_, _, _} | tail], year) do
+    filter_by_year(tail, year)
+  end
+
+  defp filter_by_country(wines, country)
+  defp filter_by_country(wines, nil), do: wines
+  defp filter_by_country([], _country), do: []
+
+  defp filter_by_country([{_, _, country} = wine | tail], country) do
+    [wine | filter_by_country(tail, country)]
+  end
+
+  defp filter_by_country([{_, _, _} | tail], country) do
+    filter_by_country(tail, country)
+  end
+end

elixir/wine-cellar/mix.exs

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+defmodule WineCellar.MixProject do
+  use Mix.Project
+
+  def project do
+    [
+      app: :wine_cellar,
+      version: "0.1.0",
+      # elixir: "~> 1.10",
+      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/wine-cellar/test/test_helper.exs

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+ExUnit.start()
+ExUnit.configure(exclude: :pending, trace: true, seed: 0)

elixir/wine-cellar/test/wine_cellar_test.exs

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+defmodule WineCellarTest do
+  use ExUnit.Case
+
+  describe "explain_colors/0" do
+    @tag task_id: 1
+    test "returns a keyword list" do
+      assert WineCellar.explain_colors() == [
+               white: "Fermented without skin contact.",
+               red: "Fermented with skin contact using dark-colored grapes.",
+               rose: "Fermented with some skin contact, but not enough to qualify as a red wine."
+             ]
+    end
+  end
+
+  describe "filter/3" do
+    @tag task_id: 2
+    test "works for empty cellar" do
+      assert WineCellar.filter([], :rose) == []
+    end
+
+    @tag task_id: 2
+    test "returns all wines of a chosen color" do
+      cellar = [
+        white: {"Chardonnay", 2015, "Italy"},
+        white: {"Chardonnay", 2014, "France"},
+        rose: {"Dornfelder", 2018, "Germany"},
+        red: {"Merlot", 2015, "France"},
+        white: {"Riesling ", 2017, "Germany"},
+        white: {"Pinot grigio", 2015, "Germany"},
+        red: {"Pinot noir", 2016, "France"},
+        red: {"Pinot noir", 2013, "Italy"}
+      ]
+
+      assert WineCellar.filter(cellar, :white) == [
+               {"Chardonnay", 2015, "Italy"},
+               {"Chardonnay", 2014, "France"},
+               {"Riesling ", 2017, "Germany"},
+               {"Pinot grigio", 2015, "Germany"}
+             ]
+
+      assert WineCellar.filter(cellar, :rose) == [{"Dornfelder", 2018, "Germany"}]
+    end
+
+    @tag task_id: 3
+    test "filters wines of chosen color by year" do
+      cellar = [
+        white: {"Chardonnay", 2015, "Italy"},
+        white: {"Chardonnay", 2014, "France"},
+        rose: {"Dornfelder", 2018, "Germany"},
+        red: {"Merlot", 2015, "France"},
+        white: {"Riesling ", 2017, "Germany"},
+        white: {"Pinot grigio", 2015, "Germany"},
+        red: {"Pinot noir", 2016, "France"},
+        red: {"Pinot noir", 2013, "Italy"}
+      ]
+
+      assert WineCellar.filter(cellar, :white, year: 2015) == [
+               {"Chardonnay", 2015, "Italy"},
+               {"Pinot grigio", 2015, "Germany"}
+             ]
+    end
+
+    @tag task_id: 4
+    test "filters wines of chosen color by country" do
+      cellar = [
+        white: {"Chardonnay", 2015, "Italy"},
+        white: {"Chardonnay", 2014, "France"},
+        rose: {"Dornfelder", 2018, "Germany"},
+        red: {"Merlot", 2015, "France"},
+        white: {"Riesling ", 2017, "Germany"},
+        white: {"Pinot grigio", 2015, "Germany"},
+        red: {"Pinot noir", 2016, "France"},
+        red: {"Pinot noir", 2013, "Italy"}
+      ]
+
+      assert WineCellar.filter(cellar, :red, country: "France") == [
+               {"Merlot", 2015, "France"},
+               {"Pinot noir", 2016, "France"}
+             ]
+    end
+
+    @tag task_id: 4
+    test "filters wines of chosen color by year and country" do
+      cellar = [
+        white: {"Chardonnay", 2015, "Italy"},
+        white: {"Chardonnay", 2014, "France"},
+        rose: {"Dornfelder", 2018, "Germany"},
+        red: {"Merlot", 2015, "France"},
+        white: {"Riesling ", 2017, "Germany"},
+        white: {"Pinot grigio", 2015, "Germany"},
+        red: {"Pinot noir", 2016, "France"},
+        red: {"Pinot noir", 2013, "Italy"}
+      ]
+
+      assert WineCellar.filter(cellar, :white, year: 2015, country: "Germany") == [
+               {"Pinot grigio", 2015, "Germany"}
+             ]
+    end
+
+    @tag task_id: 4
+    test "filters wines of chosen color by country and year" do
+      cellar = [
+        white: {"Chardonnay", 2015, "Italy"},
+        white: {"Chardonnay", 2014, "France"},
+        rose: {"Dornfelder", 2018, "Germany"},
+        red: {"Merlot", 2015, "France"},
+        white: {"Riesling ", 2017, "Germany"},
+        white: {"Pinot grigio", 2015, "Germany"},
+        red: {"Pinot noir", 2016, "France"},
+        red: {"Pinot noir", 2013, "Italy"}
+      ]
+
+      assert WineCellar.filter(cellar, :red, country: "France", year: 2015) == [
+               {"Merlot", 2015, "France"}
+             ]
+    end
+  end
+end