matching_brackets

elixir/matching-brackets/.exercism/config.json

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+{
+  "authors": [
+    "jimmbraddock"
+  ],
+  "contributors": [
+    "angelikatyborska",
+    "Cohen-Carlisle",
+    "devonestes",
+    "lex57ukr",
+    "lpil",
+    "neenjaw",
+    "parkerl",
+    "sotojuan",
+    "waiting-for-dev",
+    "workingjubilee"
+  ],
+  "files": {
+    "solution": [
+      "lib/matching_brackets.ex"
+    ],
+    "test": [
+      "test/matching_brackets_test.exs"
+    ],
+    "example": [
+      ".meta/example.ex"
+    ]
+  },
+  "blurb": "Make sure the brackets and braces all match.",
+  "source": "Ginna Baker"
+}

elixir/matching-brackets/.exercism/metadata.json

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+{"track":"elixir","exercise":"matching-brackets","id":"7934a9822b254a919f4aa9454f9c9455","url":"https://exercism.org/tracks/elixir/exercises/matching-brackets","handle":"negrienko","is_requester":true,"auto_approve":false}

elixir/matching-brackets/.formatter.exs

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

elixir/matching-brackets/.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").
+bracket_push-*.tar
+

elixir/matching-brackets/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/matching_brackets.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/matching-brackets/README.md

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+# Matching Brackets
+
+Welcome to Matching Brackets on Exercism's Elixir Track.
+If you need help running the tests or submitting your code, check out `HELP.md`.
+
+## Instructions
+
+Given a string containing brackets `[]`, braces `{}`, parentheses `()`, or any combination thereof, verify that any and all pairs are matched and nested correctly.
+The string may also contain other characters, which for the purposes of this exercise should be ignored.
+
+## Source
+
+### Created by
+
+- @jimmbraddock
+
+### Contributed to by
+
+- @angelikatyborska
+- @Cohen-Carlisle
+- @devonestes
+- @lex57ukr
+- @lpil
+- @neenjaw
+- @parkerl
+- @sotojuan
+- @waiting-for-dev
+- @workingjubilee
+
+### Based on
+
+Ginna Baker

elixir/matching-brackets/lib/matching_brackets.ex

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+defmodule MatchingBrackets do
+  require Logger
+
+  @opening_brackets ~w"[ { ("
+  @closing_brackets ~w"] } )"
+  @bracket_pairs Enum.zip(@closing_brackets, @opening_brackets)
+
+  @doc """
+  Checks that all the brackets and braces in the string are matched correctly, and nested correctly
+  """
+  @spec check_brackets(String.t()) :: boolean
+  def check_brackets(str), do: do_check_brackets(str, [])
+
+  defguardp is_opening_bracket(char) when char in @opening_brackets
+  defguardp is_closing_bracket(char) when char in @closing_brackets
+  defguardp is_pair(closing, opening) when {closing, opening} in @bracket_pairs
+
+  # Base cases
+  defp do_check_brackets("", []), do: true
+  defp do_check_brackets("", _any), do: false
+  # Opening bracket
+  defp do_check_brackets(<<opening::binary-size(1), str::binary>>, acc) when is_opening_bracket(opening), do: do_check_brackets(str, [opening | acc])
+  # Closing bracket
+  defp do_check_brackets(<<closing::binary-size(1), str::binary>>, [opening | tail]) when is_pair(closing, opening), do: do_check_brackets(str, tail)
+  defp do_check_brackets(<<closing::binary-size(1), _str::binary>>, _acc) when is_closing_bracket(closing), do: false
+  # Not a bracket
+  defp do_check_brackets(<<_char::binary-size(1), str::binary>>, acc), do: do_check_brackets(str, acc)
+end

elixir/matching-brackets/mix.exs

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+defmodule MatchingBrackets.MixProject do
+  use Mix.Project
+
+  def project do
+    [
+      app: :matching_brackets,
+      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/matching-brackets/test/matching_brackets_test.exs

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+defmodule MatchingBracketsTest do
+  use ExUnit.Case
+
+  test "paired square brackets" do
+    assert MatchingBrackets.check_brackets("[]")
+  end
+
+  test "empty string" do
+    assert MatchingBrackets.check_brackets("")
+  end
+
+  test "unpaired brackets" do
+    refute MatchingBrackets.check_brackets("[[")
+  end
+
+  test "wrong ordered brackets" do
+    refute MatchingBrackets.check_brackets("}{")
+  end
+
+  test "wrong closing bracket" do
+    refute MatchingBrackets.check_brackets("{]")
+  end
+
+  test "paired with whitespace" do
+    assert MatchingBrackets.check_brackets("{ }")
+  end
+
+  test "partially paired brackets" do
+    refute MatchingBrackets.check_brackets("{[])")
+  end
+
+  test "simple nested brackets" do
+    assert MatchingBrackets.check_brackets("{[]}")
+  end
+
+  test "several paired brackets" do
+    assert MatchingBrackets.check_brackets("{}[]")
+  end
+
+  test "paired and nested brackets" do
+    assert MatchingBrackets.check_brackets("([{}({}[])])")
+  end
+
+  test "unopened closing brackets" do
+    refute MatchingBrackets.check_brackets("{[)][]}")
+  end
+
+  test "unpaired and nested brackets" do
+    refute MatchingBrackets.check_brackets("([{])")
+  end
+
+  test "paired and wrong nested brackets" do
+    refute MatchingBrackets.check_brackets("[({]})")
+  end
+
+  test "paired and wrong nested brackets but innermost are correct" do
+    refute MatchingBrackets.check_brackets("[({}])")
+  end
+
+  test "paired and incomplete brackets" do
+    refute MatchingBrackets.check_brackets("{}[")
+  end
+
+  test "too many closing brackets" do
+    refute MatchingBrackets.check_brackets("[]]")
+  end
+
+  test "early unexpected brackets" do
+    refute MatchingBrackets.check_brackets(")()")
+  end
+
+  test "early mismatched brackets" do
+    refute MatchingBrackets.check_brackets("{)()")
+  end
+
+  test "math expression" do
+    assert MatchingBrackets.check_brackets("(((185 + 223.85) * 15) - 543)/2")
+  end
+
+  test "complex latex expression" do
+    assert MatchingBrackets.check_brackets(
+             "\\left(\\begin{array}{cc} \\frac{1}{3} & x\\\\ \\mathrm{e}^{x} &... x^2 \\end{array}\\right)"
+           )
+  end
+end

elixir/matching-brackets/test/test_helper.exs

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