diff --git a/.dialyzer_ignore.exs b/.dialyzer_ignore.exs
new file mode 100644
index 0000000..05a9f48
--- /dev/null
+++ b/.dialyzer_ignore.exs
@@ -0,0 +1,9 @@
+# You can get the spec for these errors to ignore by running:
+#     $ mix dialyzer --format short
+# ...and then taking that "short" output and either reproducing it whole here or by
+# pulling out the file and error atom.
+#
+# More info in the Dialyxir README:
+# https://github.com/jeremyjh/dialyxir#elixir-term-format
+[
+]
diff --git a/.envrc b/.envrc
new file mode 100644
index 0000000..051d09d
--- /dev/null
+++ b/.envrc
@@ -0,0 +1 @@
+eval "$(lorri direnv)"
diff --git a/.formatter.exs b/.formatter.exs
new file mode 100644
index 0000000..b3d6784
--- /dev/null
+++ b/.formatter.exs
@@ -0,0 +1,4 @@
+[
+  line_length: 140,
+  inputs: ["{mix,.formatter}.exs", "{config,lib,test}/**/*.{ex,exs}"]
+]
diff --git a/.github/dependabot.yml b/.github/dependabot.yml
new file mode 100644
index 0000000..fe012c8
--- /dev/null
+++ b/.github/dependabot.yml
@@ -0,0 +1,8 @@
+version: 2
+updates:
+- package-ecosystem: mix
+  directory: "/"
+  schedule:
+    interval: weekly
+    time: "12:00"
+  open-pull-requests-limit: 10
diff --git a/.github/workflows/elixir-build-and-test.yml b/.github/workflows/elixir-build-and-test.yml
new file mode 100644
index 0000000..0007d8f
--- /dev/null
+++ b/.github/workflows/elixir-build-and-test.yml
@@ -0,0 +1,67 @@
+name: ExUnit Tests
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - '*'
+
+jobs:
+  test:
+    name: ExUnit Tests
+    runs-on: [ubuntu-20.04]
+    env:
+      MIX_ENV: test
+
+    strategy:
+      matrix:
+        elixir: ['1.12.3', '1.13.1']
+        otp: ['24.1']
+    steps:
+    - uses: actions/checkout@v2
+    - name: Setup elixir
+      uses: erlef/setup-beam@v1
+      with:
+        elixir-version: ${{matrix.elixir}}
+        otp-version: ${{matrix.otp}}
+    - name: Cache Dependency Sources
+      uses: actions/cache@v2
+      id: deps-cache
+      with:
+        path: deps
+        # If you ever need to clear the cache, increment the number after "v1" here
+        key: dependencies-v1-${{matrix.elixir}}-${{ hashFiles('**/mix.lock') }}
+        restore-keys: dependencies-${{ hashFiles('**/mix.lock') }}
+    - name: Cache Compiled Files
+      uses: actions/cache@v2
+      with:
+        path: _build/test/
+        key: compiled-test-${{matrix.elixir}}-${{ hashFiles('**/mix.lock') }}
+        restore-keys: compiled-test-${{matrix.elixir}}
+    # In my experience, I have issues with incremental builds maybe 1 in 100
+    # times that are fixed by doing a full recompile.
+    # In order to not waste dev time on such trivial issues (while also reaping
+    # the time savings of incremental builds for *most* day-to-day development),
+    # I force a full recompile only on builds that we retry.
+    - name: Clean
+      if: github.run_attempt != '1'
+      run: | 
+        mix deps.clean --all
+        mix clean
+    - name: Install Dependencies
+      run: mix deps.get
+    - name: Build
+      run: mix compile --all-warnings --warnings-as-errors
+    # If the compile fails, it's likely due to a warning. Go ahead and run the tests
+    # to give the devs feedback and save them some time.
+    - name: Run Tests
+      # You might consider adding the --stale flag here as well.
+      # Doing so will cause Mix to attempt to run only the tests that reference modules
+      # that have changed since the last CI run.
+      # https://hexdocs.pm/mix/1.12/Mix.Tasks.Test.html#module-the-stale-option
+      run: mix test
+      if: always()
+
+    # TODO: Log test coverage
diff --git a/.github/workflows/elixir-dialyzer.yml b/.github/workflows/elixir-dialyzer.yml
new file mode 100644
index 0000000..dfacdbd
--- /dev/null
+++ b/.github/workflows/elixir-dialyzer.yml
@@ -0,0 +1,46 @@
+name: Elixir Dialyzer
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - '*'
+
+jobs:
+  dialyzer:
+    name: Run Dialyzer type checking
+    runs-on: [ubuntu-20.04]
+
+    strategy:
+      matrix:
+        elixir: ['1.13.1']
+        otp: ['24.1']
+    steps:
+      - uses: actions/checkout@v2
+      - name: Setup elixir
+        uses: erlef/setup-beam@v1
+        with:
+          elixir-version: ${{matrix.elixir}}
+          otp-version: ${{matrix.otp}}
+      - name: Cache Dependency Sources
+        uses: actions/cache@v2
+        id: deps-cache
+        with:
+          path: deps
+          # If you ever need to clear the cache, increment the number after "v1" here
+          key: dependencies-v1-${{matrix.elixir}}-${{ hashFiles('**/mix.lock') }}
+          restore-keys: dependencies-${{ hashFiles('**/mix.lock') }}
+      - name: Cache Compiled Files
+        uses: actions/cache@v2
+        with:
+          path: _build/dev/
+          key: compiled-dev-${{matrix.elixir}}-${{ hashFiles('**/mix.lock') }}
+          restore-keys: compiled-dev-${{matrix.elixir}}
+      - name: Install Dependencies
+        run: mix deps.get
+      - name: Generate PLT
+        run: mix dialyzer --plt
+      - name: Run Dialyzer
+        run: mix dialyzer
diff --git a/.github/workflows/elixir-quality-checks.yml b/.github/workflows/elixir-quality-checks.yml
new file mode 100644
index 0000000..860a2fa
--- /dev/null
+++ b/.github/workflows/elixir-quality-checks.yml
@@ -0,0 +1,50 @@
+name: Elixir Quality Checks
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - '*'
+
+jobs:
+  quality_checks:
+    runs-on: ubuntu-latest
+    env:
+      MIX_ENV: test
+
+    strategy:
+      matrix:
+        elixir: ['1.13.1']
+        otp: ['24.1']
+    steps:
+    - uses: actions/checkout@v2
+    - name: Setup elixir
+      uses: erlef/setup-beam@v1
+      with:
+        elixir-version: ${{matrix.elixir}}
+        otp-version: ${{matrix.otp}}
+    - name: Cache Dependency Sources
+      uses: actions/cache@v2
+      id: deps-cache
+      with:
+        path: deps
+        # If you ever need to clear the cache, increment the number after "v1" here
+        key: dependencies-v1-${{matrix.elixir}}-${{ hashFiles('**/mix.lock') }}
+        restore-keys: dependencies-${{ hashFiles('**/mix.lock') }}
+    - name: Cache Compiled Files
+      uses: actions/cache@v2
+      with:
+        path: _build/test/
+        key: compiled-test-${{matrix.elixir}}-${{ hashFiles('**/mix.lock') }}
+        restore-keys: compiled-test-${{matrix.elixir}}
+    - name: Install Dependencies
+      run: mix deps.get
+    - name: Run Credo
+      run: mix credo
+    # The format check gets run even if Credo fails so that
+    # we give the devs as much feedback as possible & save some time.
+    - name: Check Formatting
+      run: mix format --check-formatted
+      if: always()
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..b263cd1
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,10 @@
+/_build
+/cover
+/deps
+/doc
+/.fetch
+erl_crash.dump
+*.ez
+*.beam
+/config/*.secret.exs
+.elixir_ls/
diff --git a/.tool-versions b/.tool-versions
new file mode 100644
index 0000000..5032e78
--- /dev/null
+++ b/.tool-versions
@@ -0,0 +1,7 @@
+# This lists the versions ASDF should use with this project.
+# If you're using ASDF to manage your Elixir runtimes, you
+# can do:
+# $ asdf install
+# to get going quickly.
+elixir 1.12.3-otp-24
+erlang 24.1
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..6c955cf
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2021 Tyler A. Young
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..d3e1e15
--- /dev/null
+++ b/README.md
@@ -0,0 +1 @@
+# ZipZip
diff --git a/config/.credo.exs b/config/.credo.exs
new file mode 100644
index 0000000..2b2bcf3
--- /dev/null
+++ b/config/.credo.exs
@@ -0,0 +1,163 @@
+# This file contains the configuration for Credo and you are probably reading
+# this after creating it with `mix credo.gen.config`.
+#
+# If you find anything wrong or unclear in this file, please report an
+# issue on GitHub: https://github.com/rrrene/credo/issues
+#
+%{
+  #
+  # You can have as many configs as you like in the `configs:` field.
+  configs: [
+    %{
+      #
+      # Run any exec using `mix credo -C <name>`. If no exec name is given
+      # "default" is used.
+      #
+      name: "default",
+      #
+      # These are the files included in the analysis:
+      files: %{
+        #
+        # You can give explicit globs or simply directories.
+        # In the latter case `**/*.{ex,exs}` will be used.
+        #
+        included: ["lib/", "src/", "test/", "web/", "apps/"],
+        excluded: [~r"/_build/", ~r"/deps/", ~r"/node_modules/", ~r"/data/"]
+      },
+      #
+      # Load and configure plugins here:
+      #
+      plugins: [],
+      #
+      # If you create your own checks, you must specify the source files for
+      # them here, so they can be loaded by Credo before running the analysis.
+      #
+      requires: [
+        "config/credo_checks/explicitly_ignore_return_values.ex"
+      ],
+      #
+      # If you want to enforce a style guide and need a more traditional linting
+      # experience, you can change `strict` to `true` below:
+      #
+      strict: true,
+      #
+      # If you want to use uncolored output by default, you can change `color`
+      # to `false` below:
+      #
+      color: true,
+      #
+      # You can customize the parameters of any check by adding a second element
+      # to the tuple.
+      #
+      # To disable a check put `false` as second element:
+      #
+      #     {Credo.Check.Design.DuplicatedCode, false}
+      #
+      checks: [
+        #
+        ## Consistency Checks
+        #
+        {Credo.Check.Consistency.ExceptionNames, []},
+        {Credo.Check.Consistency.LineEndings, []},
+        {Credo.Check.Consistency.ParameterPatternMatching, []},
+        {Credo.Check.Consistency.SpaceAroundOperators, []},
+        {Credo.Check.Consistency.SpaceInParentheses, []},
+        {Credo.Check.Consistency.TabsOrSpaces, []},
+
+        #
+        ## Design Checks
+        #
+        # You can customize the priority of any check
+        # Priority values are: `low, normal, high, higher`
+        #
+        {Credo.Check.Design.AliasUsage, [priority: :low, if_nested_deeper_than: 2, if_called_more_often_than: 0]},
+        # Don't cause to-do comments to fail
+        {Credo.Check.Design.TagTODO, [exit_status: 0]},
+        {Credo.Check.Design.TagFIXME, []},
+
+        #
+        ## Readability Checks
+        #
+        {Credo.Check.Readability.AliasOrder, []},
+        {Credo.Check.Readability.FunctionNames, []},
+        {Credo.Check.Readability.LargeNumbers, []},
+        {Credo.Check.Readability.MaxLineLength, [priority: :low, max_length: 140]},
+        {Credo.Check.Readability.ModuleAttributeNames, []},
+        {Credo.Check.Readability.ModuleDoc, []},
+        {Credo.Check.Readability.ModuleNames, []},
+        {Credo.Check.Readability.ParenthesesInCondition, []},
+        {Credo.Check.Readability.ParenthesesOnZeroArityDefs, []},
+        {Credo.Check.Readability.PredicateFunctionNames, []},
+        {Credo.Check.Readability.PreferImplicitTry, []},
+        {Credo.Check.Readability.RedundantBlankLines, []},
+        {Credo.Check.Readability.Semicolons, []},
+        {Credo.Check.Readability.SpaceAfterCommas, []},
+        {Credo.Check.Readability.StringSigils, []},
+        {Credo.Check.Readability.TrailingBlankLine, []},
+        {Credo.Check.Readability.TrailingWhiteSpace, []},
+        {Credo.Check.Readability.UnnecessaryAliasExpansion, []},
+        {Credo.Check.Readability.VariableNames, []},
+
+        #
+        ## Refactoring Opportunities
+        #
+        {Credo.Check.Refactor.CondStatements, []},
+        {Credo.Check.Refactor.CyclomaticComplexity, []},
+        {Credo.Check.Refactor.FunctionArity, []},
+        {Credo.Check.Refactor.LongQuoteBlocks, []},
+        {Credo.Check.Refactor.MatchInCondition, []},
+        {Credo.Check.Refactor.NegatedConditionsInUnless, []},
+        {Credo.Check.Refactor.NegatedConditionsWithElse, []},
+        {Credo.Check.Refactor.Nesting, [max_nesting: 3]},
+        {Credo.Check.Refactor.UnlessWithElse, []},
+        {Credo.Check.Refactor.WithClauses, []},
+
+        #
+        ## Warnings
+        #
+        {Credo.Check.Warning.BoolOperationOnSameValues, []},
+        {Credo.Check.Warning.ExpensiveEmptyEnumCheck, []},
+        {Credo.Check.Warning.IExPry, []},
+        {Credo.Check.Warning.IoInspect, []},
+        {Credo.Check.Warning.MixEnv, []},
+        {Credo.Check.Warning.OperationOnSameValues, []},
+        {Credo.Check.Warning.OperationWithConstantResult, []},
+        {Credo.Check.Warning.RaiseInsideRescue, []},
+        {Credo.Check.Warning.UnusedEnumOperation, []},
+        {Credo.Check.Warning.UnusedFileOperation, []},
+        {Credo.Check.Warning.UnusedKeywordOperation, []},
+        {Credo.Check.Warning.UnusedListOperation, []},
+        {Credo.Check.Warning.UnusedPathOperation, []},
+        {Credo.Check.Warning.UnusedRegexOperation, []},
+        {Credo.Check.Warning.UnusedStringOperation, []},
+        {Credo.Check.Warning.UnusedTupleOperation, []},
+
+        #
+        # Controversial and experimental checks (opt-in, just replace `false` with `[]`)
+        #
+        {Credo.Check.Consistency.MultiAliasImportRequireUse, []},
+        # Tyler says: I don't like this one... it just enforces that you always name your unused vars the *same* way
+        #             either anonymously (like `_`) or with a real name (like `_client`)
+        {Credo.Check.Consistency.UnusedVariableNames, false},
+        # Tyler says: I like this one
+        {Credo.Check.Design.DuplicatedCode, []},
+        {Credo.Check.Readability.AliasAs, []},
+        {Credo.Check.Readability.MultiAlias, []},
+        {Credo.Check.Readability.Specs, false},
+        {Credo.Check.Readability.SeparateAliasRequire, false},
+        {Credo.Check.Readability.SinglePipe, []},
+        {Credo.Check.Readability.WithCustomTaggedTuple, []},
+        {Credo.Check.Refactor.ABCSize, false},
+        {Credo.Check.Refactor.AppendSingleItem, []},
+        {Credo.Check.Refactor.DoubleBooleanNegation, []},
+        {Credo.Check.Refactor.ModuleDependencies, false},
+        {Credo.Check.Refactor.PipeChainStart, false},
+        # Tyler says: I like this one
+        {Credo.Check.Refactor.VariableRebinding, []},
+        # Tyler says: I like this one
+        {Credo.Check.Warning.MapGetUnsafePass, []},
+        {Credo.Check.Warning.UnsafeToAtom, []}
+      ]
+    }
+  ]
+}
diff --git a/elixir.nix b/elixir.nix
new file mode 100644
index 0000000..4696014
--- /dev/null
+++ b/elixir.nix
@@ -0,0 +1,9 @@
+{ mkDerivation }:
+
+mkDerivation rec {
+  version = "1.13.0";
+
+  # nixnix-prefetch-url --unpack https://github.com/elixir-lang/elixir/archive/v1.13.0.tar.gz
+  sha256 = "1rkrx9kbs2nhkmzydm02r4wkb8wxwmg8iv0nqilpzj0skkxd6k8w";
+  minimumOTPVersion = "24";
+}
diff --git a/erlang.nix b/erlang.nix
new file mode 100644
index 0000000..290ea78
--- /dev/null
+++ b/erlang.nix
@@ -0,0 +1,7 @@
+{ mkDerivation, fetchurl }:
+
+mkDerivation rec {
+  version = "24.1";
+  # nix-prefetch-url --unpack https://github.com/erlang/otp/archive/OTP-24.0.5.tar.gz
+  sha256 = "1zxiqilnjrja2ihrsnpzlz2achkws1b7dnliw5qnzvz2sn9gf6fx";
+}
diff --git a/lib/zipper.ex b/lib/zipper.ex
new file mode 100644
index 0000000..80b698b
--- /dev/null
+++ b/lib/zipper.ex
@@ -0,0 +1,3 @@
+defmodule Zipper do
+  @moduledoc false
+end
diff --git a/mix.exs b/mix.exs
new file mode 100644
index 0000000..c3d9cd5
--- /dev/null
+++ b/mix.exs
@@ -0,0 +1,43 @@
+defmodule ElixirStartingPoint.MixProject do
+  use Mix.Project
+
+  def project do
+    [
+      app: :zipzip,
+      version: "0.1.0",
+      build_path: "_build",
+      deps_path: "deps",
+      lockfile: "mix.lock",
+      elixir: "~> 1.12",
+      consolidate_protocols: Mix.env() != :test,
+      deps: deps(),
+      test_coverage: [tool: ExCoveralls],
+      preferred_cli_env: [
+        coveralls: :test,
+        "coveralls.detail": :test,
+        "coveralls.html": :test
+      ],
+      dialyzer: [
+        plt_add_apps: [:elixir, :mix],
+        flags: [
+          :error_handling,
+          :race_conditions,
+          :underspecs
+        ],
+        ignore_warnings: ".dialyzer_ignore.exs"
+      ]
+    ]
+  end
+
+  def application do
+    []
+  end
+
+  defp deps do
+    [
+      {:credo, "~> 1.6.1", only: [:dev, :test], runtime: false},
+      {:dialyxir, "~> 1.1", only: [:dev, :test], runtime: false},
+      {:excoveralls, "~> 0.14", only: [:dev, :test], runtime: false}
+    ]
+  end
+end
diff --git a/mix.lock b/mix.lock
new file mode 100644
index 0000000..5e0cc11
--- /dev/null
+++ b/mix.lock
@@ -0,0 +1,17 @@
+%{
+  "bunt": {:hex, :bunt, "0.2.0", "951c6e801e8b1d2cbe58ebbd3e616a869061ddadcc4863d0a2182541acae9a38", [:mix], [], "hexpm", "7af5c7e09fe1d40f76c8e4f9dd2be7cebd83909f31fee7cd0e9eadc567da8353"},
+  "certifi": {:hex, :certifi, "2.8.0", "d4fb0a6bb20b7c9c3643e22507e42f356ac090a1dcea9ab99e27e0376d695eba", [:rebar3], [], "hexpm", "6ac7efc1c6f8600b08d625292d4bbf584e14847ce1b6b5c44d983d273e1097ea"},
+  "credo": {:hex, :credo, "1.6.2", "2f82b29a47c0bb7b72f023bf3a34d151624f1cbe1e6c4e52303b05a11166a701", [:mix], [{:bunt, "~> 0.2.0", [hex: :bunt, repo: "hexpm", optional: false]}, {:file_system, "~> 0.2.8", [hex: :file_system, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "ae9dc112bc368e7b145c547bec2ed257ef88955851c15057c7835251a17211c6"},
+  "dialyxir": {:hex, :dialyxir, "1.1.0", "c5aab0d6e71e5522e77beff7ba9e08f8e02bad90dfbeffae60eaf0cb47e29488", [:mix], [{:erlex, ">= 0.2.6", [hex: :erlex, repo: "hexpm", optional: false]}], "hexpm", "07ea8e49c45f15264ebe6d5b93799d4dd56a44036cf42d0ad9c960bc266c0b9a"},
+  "erlex": {:hex, :erlex, "0.2.6", "c7987d15e899c7a2f34f5420d2a2ea0d659682c06ac607572df55a43753aa12e", [:mix], [], "hexpm", "2ed2e25711feb44d52b17d2780eabf998452f6efda104877a3881c2f8c0c0c75"},
+  "excoveralls": {:hex, :excoveralls, "0.14.4", "295498f1ae47bdc6dce59af9a585c381e1aefc63298d48172efaaa90c3d251db", [:mix], [{:hackney, "~> 1.16", [hex: :hackney, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "e3ab02f2df4c1c7a519728a6f0a747e71d7d6e846020aae338173619217931c1"},
+  "file_system": {:hex, :file_system, "0.2.10", "fb082005a9cd1711c05b5248710f8826b02d7d1784e7c3451f9c1231d4fc162d", [:mix], [], "hexpm", "41195edbfb562a593726eda3b3e8b103a309b733ad25f3d642ba49696bf715dc"},
+  "hackney": {:hex, :hackney, "1.18.0", "c4443d960bb9fba6d01161d01cd81173089686717d9490e5d3606644c48d121f", [:rebar3], [{:certifi, "~>2.8.0", [hex: :certifi, repo: "hexpm", optional: false]}, {:idna, "~>6.1.0", [hex: :idna, repo: "hexpm", optional: false]}, {:metrics, "~>1.0.0", [hex: :metrics, repo: "hexpm", optional: false]}, {:mimerl, "~>1.1", [hex: :mimerl, repo: "hexpm", optional: false]}, {:parse_trans, "3.3.1", [hex: :parse_trans, repo: "hexpm", optional: false]}, {:ssl_verify_fun, "~>1.1.0", [hex: :ssl_verify_fun, repo: "hexpm", optional: false]}, {:unicode_util_compat, "~>0.7.0", [hex: :unicode_util_compat, repo: "hexpm", optional: false]}], "hexpm", "9afcda620704d720db8c6a3123e9848d09c87586dc1c10479c42627b905b5c5e"},
+  "idna": {:hex, :idna, "6.1.1", "8a63070e9f7d0c62eb9d9fcb360a7de382448200fbbd1b106cc96d3d8099df8d", [:rebar3], [{:unicode_util_compat, "~>0.7.0", [hex: :unicode_util_compat, repo: "hexpm", optional: false]}], "hexpm", "92376eb7894412ed19ac475e4a86f7b413c1b9fbb5bd16dccd57934157944cea"},
+  "jason": {:hex, :jason, "1.3.0", "fa6b82a934feb176263ad2df0dbd91bf633d4a46ebfdffea0c8ae82953714946", [:mix], [{:decimal, "~> 1.0 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm", "53fc1f51255390e0ec7e50f9cb41e751c260d065dcba2bf0d08dc51a4002c2ac"},
+  "metrics": {:hex, :metrics, "1.0.1", "25f094dea2cda98213cecc3aeff09e940299d950904393b2a29d191c346a8486", [:rebar3], [], "hexpm", "69b09adddc4f74a40716ae54d140f93beb0fb8978d8636eaded0c31b6f099f16"},
+  "mimerl": {:hex, :mimerl, "1.2.0", "67e2d3f571088d5cfd3e550c383094b47159f3eee8ffa08e64106cdf5e981be3", [:rebar3], [], "hexpm", "f278585650aa581986264638ebf698f8bb19df297f66ad91b18910dfc6e19323"},
+  "parse_trans": {:hex, :parse_trans, "3.3.1", "16328ab840cc09919bd10dab29e431da3af9e9e7e7e6f0089dd5a2d2820011d8", [:rebar3], [], "hexpm", "07cd9577885f56362d414e8c4c4e6bdf10d43a8767abb92d24cbe8b24c54888b"},
+  "ssl_verify_fun": {:hex, :ssl_verify_fun, "1.1.6", "cf344f5692c82d2cd7554f5ec8fd961548d4fd09e7d22f5b62482e5aeaebd4b0", [:make, :mix, :rebar3], [], "hexpm", "bdb0d2471f453c88ff3908e7686f86f9be327d065cc1ec16fa4540197ea04680"},
+  "unicode_util_compat": {:hex, :unicode_util_compat, "0.7.0", "bc84380c9ab48177092f43ac89e4dfa2c6d62b40b8bd132b1059ecc7232f9a78", [:rebar3], [], "hexpm", "25eee6d67df61960cf6a794239566599b09e17e668d3700247bc498638152521"},
+}
diff --git a/nixpkgs.nix b/nixpkgs.nix
new file mode 100644
index 0000000..456b36d
--- /dev/null
+++ b/nixpkgs.nix
@@ -0,0 +1,4 @@
+import (fetchTarball {
+    url = "https://github.com/NixOS/nixpkgs/archive/86a3d865f4b05fb8c913980b6d470802e70fe577.tar.gz";
+    sha256 ="1fj2xxhbrjgfwsr3v4mbci0i18qy0chrfcc7ijjyk418nqxaac36";
+})
diff --git a/shell.nix b/shell.nix
new file mode 100644
index 0000000..bd6b22f
--- /dev/null
+++ b/shell.nix
@@ -0,0 +1,35 @@
+{ pkgs ? import ./nixpkgs.nix {} }:
+
+with pkgs;
+let
+  inherit (lib) optional optionals;
+
+  erlang = pkgs.beam.lib.callErlang ./erlang.nix {};
+
+  elixir = pkgs.beam.lib.callElixir ./elixir.nix {
+    inherit erlang;
+    debugInfo = true;
+  };
+
+  elixir-erlang-src = runCommand "elixir-erlang-src" {} ''
+    mkdir $out
+    ln -s ${elixir.src} $out/elixir
+    ln -s ${erlang.src} $out/otp
+  '';#used for vim configs
+in
+
+mkShell {
+  buildInputs = [ erlang elixir ]
+    ++ optional stdenv.isLinux inotify-tools
+    ++ optionals stdenv.isDarwin (with darwin.apple_sdk.frameworks; [
+      # For file_system on macOS.
+      CoreFoundation
+      CoreServices
+    ]);
+
+  shellHook = ''
+    export LOCALE_ARCHIVE=/usr/lib/locale/locale-archive
+  '';
+
+}
+
diff --git a/test.sh b/test.sh
new file mode 100755
index 0000000..426a91f
--- /dev/null
+++ b/test.sh
@@ -0,0 +1,89 @@
+#!/bin/bash
+
+# Runs the same steps locally that will be run in CI.
+# If this passes, the CI build should as well.
+
+mix credo --strict
+CREDO_RES=$?
+if [ $CREDO_RES -ne 0 ]; then
+  echo ""
+  echo "☆ ==================================== ☆"
+	echo "☆ Credo found problems with your code. ☆" >&2
+	echo "☆ Please fix the issues above before   ☆" >&2
+	echo "☆ committing.                          ☆" >&2
+  echo "☆ ==================================== ☆"
+  echo ""
+  exit $CREDO_RES
+else
+  echo ""
+  echo "★ ============================== ★"
+  echo "★   Credo linter passed.         ★"
+  echo "★ ============================== ★"
+  echo ""
+fi
+
+mix format --check-formatted
+FORMAT_RES=$?
+if [ $FORMAT_RES -ne 0 ]
+then
+  echo ""
+  echo "☆ ==================================== ☆"
+	echo "☆  Format check failed.                ☆" >&2
+	echo "☆  Please run $ mix format             ☆" >&2
+	echo "☆  before committing.                  ☆" >&2
+  echo "☆ ==================================== ☆"
+  echo ""
+  exit $FORMAT_RES
+else
+  echo ""
+  echo "★ ============================== ★"
+  echo "★   Formatting looks good!       ★"
+  echo "★ ============================== ★"
+  echo ""
+fi
+
+# You might consider adding the --stale flag here as well.
+# Doing so will cause Mix to attempt to run only the tests that reference modules
+# that have changed since the last CI run.
+# https://hexdocs.pm/mix/1.12/Mix.Tasks.Test.html#module-the-stale-optionmix test
+mix test
+TEST_RES=$?
+if [ $TEST_RES -ne 0 ]
+then
+  echo ""
+  echo "☆ ==================================== ☆"
+	echo "☆  One or more tests failed.           ☆" >&2
+	echo "☆  Please fix them before committing.  ☆" >&2
+  echo "☆ ==================================== ☆"
+  echo ""
+  exit $TEST_RES
+else
+  echo ""
+  echo "★ ============================== ★"
+  echo "★   Tests passed.                ★"
+  echo "★ ============================== ★"
+  echo ""
+fi
+
+mix dialyzer --plt
+mix dialyzer
+DIALYZER_RES=$?
+
+if [ $DIALYZER_RES -ne 0 ]
+then
+  echo ""
+  echo "☆ ========================================= ☆"
+	echo "☆  Dialyzer checks failed.                 ☆" >&2
+	echo "☆  Please fix typespecs before committing. ☆" >&2
+  echo "☆ ======================================== ☆"
+  echo ""
+  exit $DIALYZER_RES
+else
+  echo ""
+  echo "★ ============================== ★"
+  echo "★   Dialyzer passed.             ★"
+  echo "★ ============================== ★"
+  echo ""
+fi
+
+exit 0
\ No newline at end of file
diff --git a/test/test_helper.exs b/test/test_helper.exs
new file mode 100644
index 0000000..869559e
--- /dev/null
+++ b/test/test_helper.exs
@@ -0,0 +1 @@
+ExUnit.start()
diff --git a/test/zipper_test.exs b/test/zipper_test.exs
new file mode 100644
index 0000000..6a07f4d
--- /dev/null
+++ b/test/zipper_test.exs
@@ -0,0 +1,5 @@
+defmodule ZipperTest do
+  use ExUnit.Case, async: true
+
+  alias Zipper
+end