ci: activate and use CI pipeline in GitHub

.dialyzer_ignore.exs

@@ -0,0 +1,8 @@
+# Dialyzer warnings to ignore
+#
+# Protocol fallback implementation that intentionally raises.
+# This is expected behavior - the Any implementation raises Protocol.UndefinedError
+# when a struct doesn't have an explicit Toon.Encoder implementation.
+[
+  {"lib/toon/encoder.ex", :no_return}
+]

.github/workflows/ci.yml

@@ -15,18 +15,25 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        elixir: ['1.15', '1.16', '1.17', '1.18', '1.19']
-        otp: ['25', '26', '27']
+        elixir: ["1.15", "1.16", "1.17", "1.18", "1.19"]
+        otp: ["25", "26", "27", "28"]
         exclude:
-          # Elixir 1.15 doesn't support OTP 27
-          - elixir: '1.15'
-            otp: '27'
-          # Elixir 1.16 doesn't support OTP 27
-          - elixir: '1.16'
-            otp: '27'
+          # Elixir 1.15 doesn't support OTP 27+
+          - elixir: "1.15"
+            otp: "27"
+          - elixir: "1.15"
+            otp: "28"
+          # Elixir 1.16 doesn't support OTP 27+
+          - elixir: "1.16"
+            otp: "27"
+          - elixir: "1.16"
+            otp: "28"
+          # Elixir 1.17 doesn't support OTP 28
+          - elixir: "1.17"
+            otp: "28"
           # Elixir 1.19 doesn't support OTP 25
-          - elixir: '1.19'
-            otp: '25'
+          - elixir: "1.19"
+            otp: "25"
 
     steps:
       - name: Checkout code
@@ -65,8 +72,8 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        elixir: ['1.19']
-        otp: ['27']
+        elixir: ["1.19"]
+        otp: ["28"]
 
     steps:
       - name: Checkout code
@@ -75,8 +82,8 @@ jobs:
       - name: Set up Elixir
         uses: erlef/setup-beam@v1
         with:
-          elixir-version: ${{matrix.elixir}}
-          otp-version: ${{matrix.otp}}
+          elixir-version: ${{ matrix.elixir }}
+          otp-version: ${{ matrix.otp }}
 
       - name: Restore dependencies cache
         uses: actions/cache@v4
@@ -88,22 +95,27 @@ jobs:
           restore-keys: |
             ${{ runner.os }}-mix-${{ matrix.elixir }}-${{ matrix.otp }}-
 
+      - name: Restore PLT cache
+        uses: actions/cache@v4
+        with:
+          path: priv/plts
+          key: ${{ runner.os }}-plt-${{ matrix.elixir }}-${{ matrix.otp }}-${{ hashFiles('**/mix.lock') }}
+          restore-keys: |
+            ${{ runner.os }}-plt-${{ matrix.elixir }}-${{ matrix.otp }}-
+
       - name: Install dependencies
         run: mix deps.get
 
-      - name: Check formatting
-        run: mix format --check-formatted
-
-      - name: Run Credo
-        run: mix credo --strict
+      - name: Run quality checks
+        run: mix quality.ci
 
   coverage:
     name: Test Coverage
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        elixir: ['1.19']
-        otp: ['27']
+        elixir: ["1.19"]
+        otp: ["27"]
 
     steps:
       - name: Checkout code

README.md

@@ -2,6 +2,7 @@
 
 [![Hex.pm](https://img.shields.io/hexpm/v/toon.svg)](https://hex.pm/packages/toon)
 [![Documentation](https://img.shields.io/badge/docs-hexdocs-blue.svg)](https://hexdocs.pm/toon)
+[![Coverage Status](https://coveralls.io/repos/github/kentaro/toon_ex/badge.svg?branch=main)](https://coveralls.io/github/xu-chris/toon_ex?branch=main)
 
 **TOON (Token-Oriented Object Notation)** encoder and decoder for Elixir.
 

lib/toon/decode/decode.ex

@@ -8,6 +8,9 @@ defmodule Toon.Decode do
   alias Toon.Decode.{Options, StructuralParser}
   alias Toon.DecodeError
 
+  @typedoc "Decoded TOON value"
+  @type decoded :: nil | boolean() | binary() | number() | list() | map()
+
   @doc """
   Decodes a TOON format string to Elixir data.
 
@@ -94,7 +97,7 @@ defmodule Toon.Decode do
       iex> Toon.Decode.decode!("count: 42")
       %{"count" => 42}
   """
-  @spec decode!(String.t(), keyword()) :: term()
+  @spec decode!(String.t(), keyword()) :: decoded()
   def decode!(string, opts \\ []) when is_binary(string) do
     case decode(string, opts) do
       {:ok, result} -> result
@@ -104,7 +107,7 @@ defmodule Toon.Decode do
 
   # Private functions
 
-  @spec do_decode(String.t(), map()) :: term()
+  @spec do_decode(String.t(), map()) :: decoded()
   defp do_decode(string, opts) do
     # Use structural parser for full TOON support
     case StructuralParser.parse(string, opts) do

lib/toon/decode/structural_parser.ex

@@ -157,8 +157,6 @@ defmodule Toon.Decode.StructuralParser do
     end
   end
 
-  defp detect_root_type([]), do: {:object, nil}
-
   # Parse root primitive value (single value without key)
   defp parse_root_primitive([%{content: content}], _opts) do
     # For root primitives, we parse directly without parser combinator

lib/toon/encode/arrays.ex

@@ -49,7 +49,8 @@ defmodule Toon.Encode.Arrays do
       iex> IO.iodata_to_binary(result)
       "items[0]:"
   """
-  @spec encode_empty(String.t(), String.t() | nil) :: [iodata()]
+  @spec encode_empty(String.t(), String.t() | nil) ::
+          nonempty_list(nonempty_list(binary() | nonempty_list(binary())))
   def encode_empty(key, length_marker \\ nil) do
     marker = format_length_marker(0, length_marker)
     [[Strings.encode_key(key), "[", marker, "]", Constants.colon()]]

lib/toon/encode/objects.ex

@@ -17,7 +17,7 @@ defmodule Toon.Encode.Objects do
       iex> Toon.Encode.Objects.encode(map, 0, opts)
 
   """
-  @spec encode(map(), non_neg_integer(), map()) :: iodata()
+  @spec encode(map(), non_neg_integer(), map()) :: [iodata()]
   def encode(map, depth, opts) when is_map(map) do
     writer = Writer.new(opts.indent)
 
@@ -103,22 +103,14 @@ defmodule Toon.Encode.Objects do
 
   # Private helpers
 
-  defp append_lines(writer, [], _depth), do: writer
-
-  defp append_lines(writer, lines, depth) when is_list(lines) do
+  defp append_lines(writer, [header | data_rows], depth) do
     # For arrays, the first line is the header at current depth
     # Subsequent lines (data rows for tabular format) should be one level deeper
-    case lines do
-      [header | data_rows] ->
-        writer = Writer.push(writer, header, depth)
-
-        Enum.reduce(data_rows, writer, fn row, acc ->
-          Writer.push(acc, row, depth + 1)
-        end)
+    writer = Writer.push(writer, header, depth)
 
-      [] ->
-        writer
-    end
+    Enum.reduce(data_rows, writer, fn row, acc ->
+      Writer.push(acc, row, depth + 1)
+    end)
   end
 
   defp append_iodata(writer, iodata, _base_depth) do

lib/toon/encode/options.ex

@@ -5,6 +5,15 @@ defmodule Toon.Encode.Options do
 
   alias Toon.Constants
 
+  @typedoc "Validated encoding options"
+  @type validated :: %{
+          indent: pos_integer(),
+          delimiter: String.t(),
+          length_marker: String.t() | nil,
+          key_order: term(),
+          indent_string: String.t()
+        }
+
   @options_schema [
     indent: [
       type: :pos_integer,
@@ -90,7 +99,7 @@ defmodule Toon.Encode.Options do
       iex> Toon.Encode.Options.validate!(indent: 4)
       %{indent: 4, delimiter: ",", length_marker: nil, indent_string: "    "}
   """
-  @spec validate!(keyword()) :: map()
+  @spec validate!(keyword()) :: validated()
   def validate!(opts) when is_list(opts) do
     case validate(opts) do
       {:ok, validated} ->

lib/toon/encode/strings.ex

@@ -24,7 +24,7 @@ defmodule Toon.Encode.Strings do
       iex> Toon.Encode.Strings.encode_string("line1\\nline2") |> IO.iodata_to_binary()
       ~s("line1\\\\nline2")
   """
-  @spec encode_string(String.t(), String.t()) :: iodata()
+  @spec encode_string(String.t(), String.t()) :: binary() | nonempty_list(binary())
   def encode_string(string, delimiter \\ ",") when is_binary(string) do
     if safe_unquoted?(string, delimiter) do
       string

lib/toon/encoder.ex

@@ -32,7 +32,7 @@ defprotocol Toon.Encoder do
 
   Returns IO data that can be converted to a string.
   """
-  @spec encode(t, keyword()) :: iodata()
+  @spec encode(t, keyword()) :: iodata() | map()
   def encode(value, opts)
 end
 
@@ -42,19 +42,15 @@ defimpl Toon.Encoder, for: Any do
 
     quote do
       defimpl Toon.Encoder, for: unquote(module) do
-        def encode(struct, opts) do
-          map =
-            struct
-            |> Map.take(unquote(fields))
-            |> Map.new(fn {k, v} -> {to_string(k), v} end)
-
-          Toon.Encode.encode!(map, opts)
+        def encode(struct, _opts) do
+          struct
+          |> Map.take(unquote(fields))
+          |> Map.new(fn {k, v} -> {to_string(k), Toon.Utils.normalize(v)} end)
         end
       end
     end
   end
 
-  @spec encode(struct(), keyword()) :: no_return()
   def encode(%_{} = struct, _opts) do
     raise Protocol.UndefinedError,
       protocol: @protocol,
@@ -74,7 +70,6 @@ defimpl Toon.Encoder, for: Any do
       """
   end
 
-  @spec encode(term(), keyword()) :: no_return()
   def encode(value, _opts) do
     raise Protocol.UndefinedError,
       protocol: @protocol,
@@ -87,7 +82,7 @@ defimpl Toon.Encoder, for: Any do
         only
 
       except = Keyword.get(opts, :except) ->
-        Map.keys(struct) -- ([:__struct__] -- except)
+        Map.keys(struct) -- [:__struct__ | except]
 
       true ->
         Map.keys(struct) -- [:__struct__]

lib/toon/shared/utils.ex

@@ -194,6 +194,19 @@ defmodule Toon.Utils do
     Enum.map(value, &normalize/1)
   end
 
+  # Structs - dispatch to Toon.Encoder protocol
+  def normalize(%{__struct__: _} = struct) do
+    result = Toon.Encoder.encode(struct, [])
+
+    # If encoder returns iodata (string), convert it to binary
+    # If encoder returns a map (from @derive), use it directly
+    case result do
+      binary when is_binary(binary) -> binary
+      map when is_map(map) -> map
+      iodata -> IO.iodata_to_binary(iodata)
+    end
+  end
+
   def normalize(value) when is_map(value) do
     Map.new(value, fn {k, v} ->
       {to_string(k), normalize(v)}

mix.exs

@@ -26,7 +26,8 @@ defmodule Toon.MixProject do
           :underspecs,
           :unmatched_returns,
           :unknown
-        ]
+        ],
+        ignore_warnings: ".dialyzer_ignore.exs"
       ],
       aliases: aliases()
     ]
@@ -44,7 +45,7 @@ defmodule Toon.MixProject do
     ]
   end
 
-  defp elixirc_paths(:test), do: ["lib"]
+  defp elixirc_paths(:test), do: ["lib", "test/fixtures"]
   defp elixirc_paths(_), do: ["lib"]
 
   def application do

test/fixtures/test_structs.ex

@@ -0,0 +1,28 @@
+defmodule Toon.Fixtures.UserWithExcept do
+  @moduledoc false
+  @derive {Toon.Encoder, except: [:password]}
+  defstruct [:name, :email, :password]
+end
+
+defmodule Toon.Fixtures.CustomDate do
+  @moduledoc "Test struct with explicit Toon.Encoder implementation"
+  defstruct [:year, :month, :day]
+end
+
+defimpl Toon.Encoder, for: Toon.Fixtures.CustomDate do
+  def encode(%{year: y, month: m, day: d}, _opts) do
+    "#{y}-#{String.pad_leading(to_string(m), 2, "0")}-#{String.pad_leading(to_string(d), 2, "0")}"
+  end
+end
+
+defmodule Toon.Fixtures.Person do
+  @moduledoc false
+  @derive Toon.Encoder
+  defstruct [:name, :age]
+end
+
+defmodule Toon.Fixtures.Company do
+  @moduledoc false
+  @derive Toon.Encoder
+  defstruct [:name, :ceo]
+end