Exercism: Pacman Rules

elixir/pacman-rules/.exercism/config.json

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+{
+  "blurb": "Learn about booleans by implementing the rules of the Pac-Man game.",
+  "authors": [
+    "neenjaw"
+  ],
+  "contributors": [
+    "Cohen-Carlisle"
+  ],
+  "files": {
+    "solution": [
+      "lib/rules.ex"
+    ],
+    "test": [
+      "test/rules_test.exs"
+    ],
+    "exemplar": [
+      ".meta/exemplar.ex"
+    ]
+  },
+  "language_versions": ">=1.10"
+}

elixir/pacman-rules/.exercism/metadata.json

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+{"track":"elixir","exercise":"pacman-rules","id":"0e1b851e229a4567b01888d36d142a83","url":"https://exercism.org/tracks/elixir/exercises/pacman-rules","handle":"JBiason","is_requester":true,"auto_approve":false}

elixir/pacman-rules/.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").
+booleans-*.tar
+

elixir/pacman-rules/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/rules.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)
+- [Exercism's support channel on gitter](https://gitter.im/exercism/support)
+- 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.
+If you can't find what you're looking for in the documentation, feel free to ask help in the Exercism's BEAM [gitter channel](https://gitter.im/exercism/xerlang).

elixir/pacman-rules/HINTS.md

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+# Hints
+
+## General
+
+- Don't worry about how the arguments are derived, just focus on combining the arguments to return the intended result.
+
+## 1. Define if pac-man can eat a ghost
+
+- You need to define a [named function][named-function] with 2 arguments. The first argument is a [boolean][boolean] value, whether pac-man has a power pellet active. The second argument is a [boolean][boolean] value, whether pac-man is touching a ghost.
+- The function must return a [boolean][boolean] value.
+- You can use the [boolean][boolean] operator [`and/2`][boolean-function] to combine the arguments for a result.
+
+## 2. Define if pac-man scores
+
+- You need to define a [named function][named-function] with 2 arguments. The first argument is a [boolean][boolean] value, whether pac-man is touching a power pellet. The second argument is a [boolean][boolean] value, whether pac-man is touching a dot.
+- The function must return a [boolean][boolean] value.
+- You can use the [boolean][boolean] operator [`or/2`][boolean-function] to combine the arguments for a result.
+
+## 3. Define if pac-man loses
+
+- You need to define a [named function][named-function] with 2 arguments. The first argument is a [boolean][boolean] value, whether pac-man has a power pellet active. The second argument is a [boolean][boolean] value, whether pac-man is touching a ghost.
+- The function must return a [boolean][boolean] value.
+- You can use the [boolean][boolean] operators [`and/2`][boolean-function] and [`not/1`][boolean-function] to combine the arguments for a result.
+
+## 4. Define if pac-man wins
+
+- You need to define a [named function][named-function] with 3 arguments. The second argument is a [boolean][boolean] value, whether pac-man has eaten all of the dots. The first argument is a [boolean][boolean] value, whether pac-man has a power pellet active. The second argument is a [boolean][boolean] value, whether pac-man is touching a ghost.
+- The function must return a [boolean][boolean] value.
+- You can use the [boolean][boolean] operators [`and/2`][boolean-function] and [`not/1`][boolean-function] to combine the arguments and results of invoked functions.
+
+[named-function]: https://elixir-lang.org/getting-started/modules-and-functions.html#named-functions
+[boolean]: https://elixir-lang.org/getting-started/basic-types.html#booleans
+[boolean-function]: https://elixir-lang.org/getting-started/basic-operators.html

elixir/pacman-rules/README.md

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+# Pacman Rules
+
+Welcome to Pacman Rules 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
+
+## Booleans
+
+Elixir represents true and false values with the boolean type. There are only two values: _true_ and _false_. These values can be bound to a variable:
+
+```elixir
+true_variable = true
+false_variable = false
+```
+
+We can evaluate strict boolean expressions using the `and/2`, `or/2`, and `not/1` operator functions.
+
+```elixir
+true_variable = true and true
+false_variable = true and false
+
+true_variable = false or true
+false_variable = false or false
+
+true_variable = not false
+false_variable = not true
+```
+
+When writing a function that returns a boolean value, it is idiomatic to end the function name with a `?`.
+
+```elixir
+def either_true?(a, b) do
+  a or b
+end
+```
+
+## Instructions
+
+In this exercise, you need to translate some rules from the classic game Pac-Man into Elixir functions.
+
+You have four rules to translate, all related to the game states.
+
+> Don't worry about how the arguments are derived, just focus on combining the arguments to return the intended result.
+
+## 1. Define if Pac-Man eats a ghost
+
+Define the `Rules.eat_ghost?/2` function that takes two arguments (_if Pac-Man has a power pellet active_ and _if Pac-Man is touching a ghost_) and returns a boolean value if Pac-Man is able to eat the ghost. The function should return true only if Pac-Man has a power pellet active and is touching a ghost.
+
+```elixir
+Rules.eat_ghost?(false, true)
+# => false
+```
+
+## 2. Define if Pac-Man scores
+
+Define the `Rules.score?/2` function that takes two arguments (_if Pac-Man is touching a power pellet_ and _if Pac-Man is touching a dot_) and returns a boolean value if Pac-Man scored. The function should return true if Pac-Man is touching a power pellet or a dot.
+
+```elixir
+Rules.score?(true, true)
+# => true
+```
+
+## 3. Define if Pac-Man loses
+
+Define the `Rules.lose?/2` function that takes two arguments (_if Pac-Man has a power pellet active_ and _if Pac-Man is touching a ghost_) and returns a boolean value if Pac-Man loses. The function should return true if Pac-Man is touching a ghost and does not have a power pellet active.
+
+```elixir
+Rules.lose?(false, true)
+# => true
+```
+
+## 4. Define if Pac-Man wins
+
+Define the `Rules.win?/3` function that takes three arguments (_if Pac-Man has eaten all of the dots_, _if Pac-Man has a power pellet active_, and _if Pac-Man is touching a ghost_) and returns a boolean value if Pac-Man wins. The function should return true if Pac-Man has eaten all of the dots and has not lost based on the arguments defined in part 3.
+
+```elixir
+Rules.win?(false, true, false)
+# => false
+```
+
+## Source
+
+### Created by
+
+- @neenjaw
+
+### Contributed to by
+
+- @Cohen-Carlisle

elixir/pacman-rules/lib/rules.ex

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+defmodule Rules do
+  def eat_ghost?(power_pellet_active, touching_ghost) do
+    power_pellet_active && touching_ghost
+  end
+
+  def score?(touching_power_pellet, touching_dot) do
+    touching_power_pellet || touching_dot
+  end
+
+  def lose?(power_pellet_active, touching_ghost) do
+    ! power_pellet_active && touching_ghost
+  end
+
+  def win?(has_eaten_all_dots, power_pellet_active, touching_ghost) do
+    has_eaten_all_dots && ! lose?(power_pellet_active, touching_ghost)
+  end
+end

elixir/pacman-rules/mix.exs

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+defmodule Rules.MixProject do
+  use Mix.Project
+
+  def project do
+    [
+      app: :pacman_rules,
+      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/pacman-rules/test/rules_test.exs

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+defmodule RulesTest do
+  use ExUnit.Case
+
+  describe "eat_ghost?/2" do
+    @tag task_id: 1
+    test "ghost gets eaten" do
+      assert Rules.eat_ghost?(true, true)
+    end
+
+    @tag task_id: 1
+    test "ghost does not get eaten because no power pellet active" do
+      refute Rules.eat_ghost?(false, true)
+    end
+
+    @tag task_id: 1
+    test "ghost does not get eaten because not touching ghost" do
+      refute Rules.eat_ghost?(true, false)
+    end
+  end
+
+  describe "score?/2" do
+    @tag task_id: 2
+    test "score when eating dot" do
+      assert Rules.score?(false, true)
+    end
+
+    @tag task_id: 2
+    test "score when eating power pellet" do
+      assert Rules.score?(true, false)
+    end
+
+    @tag task_id: 2
+    test "no score when nothing eaten" do
+      refute Rules.score?(false, false)
+    end
+  end
+
+  describe "lose?/2" do
+    @tag task_id: 3
+    test "lose if touching a ghost without a power pellet active" do
+      assert Rules.lose?(false, true)
+    end
+
+    @tag task_id: 3
+    test "don't lose if touching a ghost with a power pellet active" do
+      refute Rules.lose?(true, true)
+    end
+
+    @tag task_id: 3
+    test "don't lose if not touching a ghost" do
+      refute Rules.lose?(true, false)
+    end
+  end
+
+  describe "win?/3" do
+    @tag task_id: 4
+    test "win if all dots eaten" do
+      assert Rules.win?(true, false, false)
+    end
+
+    @tag task_id: 4
+    test "don't win if all dots eaten, but touching a ghost" do
+      refute Rules.win?(true, false, true)
+    end
+
+    @tag task_id: 4
+    test "win if all dots eaten and touching a ghost with a power pellet active" do
+      assert Rules.win?(true, true, true)
+    end
+  end
+end

elixir/pacman-rules/test/test_helper.exs

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