initial version for atomic_map, works just with maps

Author: mindreframer

.gitignore

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+/_build
+/cover
+/deps
+erl_crash.dump
+*.ez

README.md

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+# AtomicMap
+
+A small helper to convert deep hashes with mixed string/atom keys to atom-only keyed maps. Optionally with a safe option, to prevent [atom space exhaustion of the Erlang VM](https://erlangcentral.org/wiki/index.php?title=String_Conversion_To_Atom).
+
+## Usage
+
+
+```elixir
+iex> AtomicMap.convert(%{"a" => 2, "b" => %{"c" => 4}}, safe: true)
+%{a: 2, b: %{c: 4}}
+```
+
+
+
+
+## Installation
+
+If [available in Hex](https://hex.pm/docs/publish), the package can be installed as:
+
+  1. Add atomic_map to your list of dependencies in `mix.exs`:
+
+        def deps do
+          [{:atomic_map, "~> 0.0.1"}]
+        end
+
+  2. Ensure atomic_map is started before your application:
+
+        def application do
+          [applications: [:atomic_map]]
+        end
+

config/config.exs

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+# This file is responsible for configuring your application
+# and its dependencies with the aid of the Mix.Config module.
+use Mix.Config
+
+# This configuration is loaded before any dependency and is restricted
+# to this project. If another project depends on this project, this
+# file won't be loaded nor affect the parent project. For this reason,
+# if you want to provide default values for your application for
+# 3rd-party users, it should be done in your "mix.exs" file.
+
+# You can configure for your application as:
+#
+#     config :atomic_map, key: :value
+#
+# And access this configuration in your application as:
+#
+#     Application.get_env(:atomic_map, :key)
+#
+# Or configure a 3rd-party app:
+#
+#     config :logger, level: :info
+#
+
+# It is also possible to import configuration files, relative to this
+# directory. For example, you can emulate configuration per environment
+# by uncommenting the line below and defining dev.exs, test.exs and such.
+# Configuration from the imported file will override the ones defined
+# here (which is why it is important to import them last).
+#
+#     import_config "#{Mix.env}.exs"

lib/atomic_map.ex

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+defmodule AtomicMap do
+  def convert(map, opts) when is_map(map) do
+    safe = Keyword.get(opts, :safe, true)
+    map |> Enum.reduce(%{}, fn
+       # convert strings to atoms
+       {k,v}, acc when is_binary(k) and is_map(v)
+           -> Map.put(acc, as_atom(k, safe), convert(v, opts));
+       {k,v}, acc when is_map(v)
+           -> Map.put(acc, k, convert(v, opts));
+       {k,v}, acc when is_binary(k)
+           -> Map.put(acc, as_atom(k, safe), v);
+       {k,v}, acc
+           -> Map.put(acc, k, v)
+    end)
+  end
+
+  defp as_atom(s, true) when is_binary(s), do: s |> String.to_existing_atom
+  defp as_atom(s, true),                   do: s
+
+  defp as_atom(s, false) when is_binary(s), do: s |> String.to_atom
+  defp as_atom(s, false),                   do: s
+end

mix.exs

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+defmodule AtomicMap.Mixfile do
+  use Mix.Project
+
+  def project do
+    [app: :atomic_map,
+     version: "0.0.1",
+     elixir: "~> 1.2",
+     build_embedded: Mix.env == :prod,
+     start_permanent: Mix.env == :prod,
+     deps: deps]
+  end
+
+  # Configuration for the OTP application
+  #
+  # Type "mix help compile.app" for more information
+  def application do
+    [applications: [:logger]]
+  end
+
+  # Dependencies can be Hex packages:
+  #
+  #   {:mydep, "~> 0.3.0"}
+  #
+  # Or git/path repositories:
+  #
+  #   {:mydep, git: "https://github.com/elixir-lang/mydep.git", tag: "0.1.0"}
+  #
+  # Type "mix help deps" for more examples and options
+  defp deps do
+    []
+  end
+end

test/atomic_map_test.exs

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+defmodule AtomicMapTest do
+  use ExUnit.Case
+  doctest AtomicMap
+
+  test "works with maps" do
+    input    = %{"a" => 2, "b" => %{"c" => 4}}
+    expected = %{a: 2, b: %{c: 4}}
+    assert AtomicMap.convert(input, safe: true) == expected
+  end
+
+  test "raises for not existing atoms" do
+    assert_raise ArgumentError, fn ->
+      input = %{"a" => 2, "b" => %{"c" => 4}, "__not___existing__" => 5}
+      AtomicMap.convert(input, safe: true)
+    end
+  end
+end

test/test_helper.exs

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+ExUnit.start()