feat!: allow default values for optional map keys (#32)

BREAKING-CHANGE: Raises minimum Elixir version to 1.12

.github/workflows/ci.yml

@@ -11,27 +11,27 @@ jobs:
 
     strategy:
       matrix:
-        otp: [23.x, 24.x, 25.x, 26.x]
-        elixir: [1.10.x, 1.11.x, 1.12.x, 1.13.x, 1.14.x, 1.15.x]
+        otp: [25.x, 26.x, 27.x]
+        elixir: [1.12.x, 1.13.x, 1.14.x, 1.15.x, 1.16.x, 1.17.x]
         exclude:
-          - otp: 26.x
-            elixir: 1.10.x
-          - otp: 26.x
-            elixir: 1.11.x
+          - otp: 27.x
+            elixir: 1.12.x
+          - otp: 27.x
+            elixir: 1.13.x
+          - otp: 27.x
+            elixir: 1.14.x
+          - otp: 27.x
+            elixir: 1.15.x
+          - otp: 27.x
+            elixir: 1.16.x
+          - otp: 27.x
+            elixir: 1.16.x
           - otp: 26.x
             elixir: 1.12.x
           - otp: 26.x
             elixir: 1.13.x
-          - otp: 25.x
-            elixir: 1.11.x
           - otp: 25.x
             elixir: 1.12.x
-          - otp: 25.x
-            elixir: 1.10.x
-          - otp: 24.x
-            elixir: 1.10.x
-          - otp: 23.x
-            elixir: 1.15.x
 
     steps:
     - uses: actions/checkout@v2
@@ -56,14 +56,14 @@ jobs:
 
   formatter:
     runs-on: ubuntu-latest
-    name: Formatter (1.15.x/26.x)
+    name: Formatter (1.17.x/27.x)
 
     steps:
     - uses: actions/checkout@v2
     - uses: erlef/setup-beam@v1
       with:
-        otp-version: 26.x
-        elixir-version: 1.15.x
+        otp-version: 27.x
+        elixir-version: 1.17.x
     - uses: actions/cache@v3
       with:
         path: |

lib/schematic.ex

@@ -38,10 +38,11 @@ defmodule Schematic do
 
   defmodule OptionalKey do
     @enforce_keys [:key]
-    defstruct [:key]
+    defstruct [:key, default: :__SCHEMATIC_EMPTY_DEFAULT__]
 
     @opaque t :: %__MODULE__{
-              key: {any(), any()} | any()
+              key: {any(), any()} | any(),
+              default: any()
             }
   end
 
@@ -460,16 +461,20 @@ defmodule Schematic do
 
   If the key _is_ provided, it must unify according to the given schematic.
 
-  Likewise, using `dump/2` will also omit that key.
+  You can also provide a default value for an optional key with `optional/2`.
+
+  Likewise, using `dump/2` will also omit that key, unless it has a default value.
 
   ```elixir
   iex> schematic = map(%{
   ...>   "title" => str(),
-  ...>   optional("description") => str()
+  ...>   optional("description") => str(),
+  ...>   optional("kind", "technology") => str()
   ...> })
-  iex> {:ok, %{"title" => "Elixir 101", "description" =>  "An amazing programming course."}} = unify(schematic, %{"title" => "Elixir 101", "description" => "An amazing programming course."})
-  iex> {:ok, %{"title" => "Elixir 101"}} = unify(schematic, %{"title" => "Elixir 101"})
-  iex> {:ok, %{"title" => "Elixir 101"}} = dump(schematic, %{"title" => "Elixir 101"})
+  iex> {:ok, %{"title" => "Elixir 101", "description" =>  "An amazing programming course.", "kind" => "technology"}} = unify(schematic, %{"title" => "Elixir 101", "description" => "An amazing programming course."})
+  iex> {:ok, %{"title" => "Elixir 101", "kind" => "computer science"}} = unify(schematic, %{"title" => "Elixir 101", "kind" => "computer science"})
+  iex> {:ok, %{"title" => "Elixir 101", "kind" => "computer science"}} = dump(schematic, %{"title" => "Elixir 101", "kind" => "computer science"})
+  iex> {:ok, %{"title" => "Elixir 101", "kind" => "technology"}} = dump(schematic, %{"title" => "Elixir 101"})
   ```
 
   ## With `:keys` and `:values`
@@ -603,6 +608,13 @@ defmodule Schematic do
                   end
 
                 if not Map.has_key?(input, from_key) and match?(%OptionalKey{}, bpk) do
+                  acc =
+                    if bpk.default != :__SCHEMATIC_EMPTY_DEFAULT__ do
+                      Map.put(acc, to_key, bpk.default)
+                    else
+                      acc
+                    end
+
                   [{:ok, acc}, {:errors, errors}]
                 else
                   case Schematic.Unification.unify(schematic, input[from_key], dir) do
@@ -1017,4 +1029,14 @@ defmodule Schematic do
   def optional(key) do
     %OptionalKey{key: key}
   end
+
+  @doc """
+  Specifies an optional key and also a default value in the case the key is not present.
+
+  See `map/1` for more examples and explanation.
+  """
+  @spec optional(any(), any()) :: OptionalKey.t()
+  def optional(key, default) do
+    %OptionalKey{key: key, default: default}
+  end
 end

mix.exs

@@ -7,7 +7,7 @@ defmodule Schematic.MixProject do
       description: "Data validation and transformation",
       package: package(),
       version: "0.3.1",
-      elixir: "~> 1.10",
+      elixir: "~> 1.12",
       elixirc_paths: elixirc_paths(Mix.env()),
       start_permanent: Mix.env() == :prod,
       source_url: "https://github.com/mhanberg/schematic",
@@ -41,7 +41,7 @@ defmodule Schematic.MixProject do
     [
       {:telemetry, "~> 0.4 or ~> 1.0"},
       {:ex_doc, ">= 0.0.0", only: :dev, runtime: false},
-      {:stream_data, "~> 0.5.0", only: [:dev, :test], runtime: false}
+      {:stream_data, "~> 1.1", only: [:dev, :test], runtime: false}
     ]
   end
 

mix.lock

@@ -5,6 +5,6 @@
   "makeup_elixir": {:hex, :makeup_elixir, "0.16.0", "f8c570a0d33f8039513fbccaf7108c5d750f47d8defd44088371191b76492b0b", [:mix], [{:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: false]}, {:nimble_parsec, "~> 1.2.3", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "28b2cbdc13960a46ae9a8858c4bebdec3c9a6d7b4b9e7f4ed1502f8159f338e7"},
   "makeup_erlang": {:hex, :makeup_erlang, "0.1.1", "3fcb7f09eb9d98dc4d208f49cc955a34218fc41ff6b84df7c75b3e6e533cc65f", [:mix], [{:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: false]}], "hexpm", "174d0809e98a4ef0b3309256cbf97101c6ec01c4ab0b23e926a9e17df2077cbb"},
   "nimble_parsec": {:hex, :nimble_parsec, "1.2.3", "244836e6e3f1200c7f30cb56733fd808744eca61fd182f731eac4af635cc6d0b", [:mix], [], "hexpm", "c8d789e39b9131acf7b99291e93dae60ab48ef14a7ee9d58c6964f59efb570b0"},
+  "stream_data": {:hex, :stream_data, "1.1.2", "05499eaec0443349ff877aaabc6e194e82bda6799b9ce6aaa1aadac15a9fdb4d", [:mix], [], "hexpm", "129558d2c77cbc1eb2f4747acbbea79e181a5da51108457000020a906813a1a9"},
   "telemetry": {:hex, :telemetry, "1.2.1", "68fdfe8d8f05a8428483a97d7aab2f268aaff24b49e0f599faa091f1d4e7f61c", [:rebar3], [], "hexpm", "dad9ce9d8effc621708f99eac538ef1cbe05d6a874dd741de2e689c47feafed5"},
-  "stream_data": {:hex, :stream_data, "0.5.0", "b27641e58941685c75b353577dc602c9d2c12292dd84babf506c2033cd97893e", [:mix], [], "hexpm", "012bd2eec069ada4db3411f9115ccafa38540a3c78c4c0349f151fc761b9e271"},
 }

test/schematic_test.exs

@@ -508,6 +508,20 @@ defmodule SchematicTest do
                unify(schematic, %{type: 10, name: 10})
     end
 
+    test "optional keys with default value" do
+      schematic =
+        map(%{
+          optional(:name, "mitch") => str(),
+          type: int()
+        })
+
+      assert {:ok, %{type: 10, name: "mitch"}} == unify(schematic, %{type: 10})
+      assert {:ok, %{type: 10, name: "bob"}} == unify(schematic, %{type: 10, name: "bob"})
+
+      assert {:error, %{name: "expected a string"}} ==
+               unify(schematic, %{type: 10, name: 10})
+    end
+
     test "empty map" do
       schematic = map()