Merge pull request #27 from ExpressApp/typespecs

add typespecs generation

.dialyzer_ignore.exs

@@ -0,0 +1,6 @@
+[
+  # fix for `Function ExUnit.CaseTemplate.__proxy__/2 does not exist.`
+  {"", :unknown_function, 0},
+  # fix for `The pattern can never match the type.`
+  {"lib/construct.ex", :pattern_match, 447},
+]

.gitignore

@@ -14,6 +14,10 @@
 # Where 3rd-party dependencies like ExDoc output generated docs.
 /doc
 
+# Plts
+/priv/*.plt
+/priv/*.plt.hash
+
 # If the VM crashes, it generates a dump, let's ignore it too.
 erl_crash.dump
 

lib/construct.ex

@@ -61,8 +61,6 @@ defmodule Construct do
 
       unquote(pre_ast)
 
-      @type t :: %__MODULE__{}
-
       def make(params \\ %{}, opts \\ []) do
         Construct.Cast.make(__MODULE__, params, Keyword.merge(opts, unquote(opts)))
       end
@@ -104,7 +102,8 @@ defmodule Construct do
 
       Module.eval_quoted __ENV__, {:__block__, [], [
         Construct.__defstruct__(@construct_fields, @construct_fields_enforce),
-        Construct.__types__(@fields)]}
+        Construct.__types__(@fields),
+        Construct.__typespecs__(@fields)]}
     end
   end
 
@@ -114,7 +113,7 @@ defmodule Construct do
   If included structure is invalid for some reason — this macro throws an
   `Struct.DefinitionError` exception with detailed reason.
   """
-  @spec include(t) :: :ok
+  @spec include(t) :: Macro.t()
   defmacro include(struct) do
     quote do
       module = unquote(struct)
@@ -154,7 +153,7 @@ defmodule Construct do
 
       By default this option is unset. Notice that you can't use functions as a default value.
   """
-  @spec field(atom, Construct.Type.t, Keyword.t) :: :ok
+  @spec field(atom, Construct.Type.t, Keyword.t) :: Macro.t()
   defmacro field(name, type \\ :string, opts \\ [])
   defmacro field(name, opts, [do: _] = contents) do
     make_nested_field(name, contents, opts)
@@ -176,7 +175,7 @@ defmodule Construct do
   @doc """
   Alias to `c:make/2`, but raises an `Construct.MakeError` exception if params have errors.
   """
-  @callback make!(params :: map, opts :: Keyword.t) :: {:ok, t} | {:error, term}
+  @callback make!(params :: map, opts :: Keyword.t) :: t
 
   @doc """
   Alias to `c:make/2`, used to follow `c:Construct.Type.cast/1` callback.
@@ -264,6 +263,42 @@ defmodule Construct do
     end
   end
 
+  @doc false
+  def __typespecs__(fields) do
+    typespecs =
+      Enum.map(fields, fn({name, type, opts}) ->
+        type = Construct.Type.spec(type)
+
+        type =
+          case Keyword.fetch(opts, :default) do
+            {:ok, default} ->
+              typeof_default = Construct.Type.typeof(default)
+
+              if type == typeof_default do
+                type
+              else
+                quote do: unquote(type) | unquote(typeof_default)
+              end
+
+            :error ->
+              type
+          end
+
+        {name, type}
+      end)
+
+    modulespec =
+      {:%, [],
+        [
+          {:__MODULE__, [], Elixir},
+          {:%{}, [], typespecs}
+        ]}
+
+    quote do
+      @type t :: unquote(modulespec)
+    end
+  end
+
   @doc false
   def __field__(mod, name, type, opts) do
     check_field_name!(name)

lib/construct/exceptions.ex

@@ -5,8 +5,6 @@ end
 defmodule Construct.MakeError do
   defexception [:message]
 
-  @spec exception(struct_error | String.t | term) :: struct
-    when struct_error: %{reason: map, params: map}
   def exception(%{reason: reason, params: params}) when is_map(reason) do
     %__MODULE__{message: inspect(traverse_errors(reason, params))}
   end

lib/construct/type.ex

@@ -121,7 +121,7 @@ defmodule Construct.Type do
       :error
 
   """
-  @spec cast(t, term, options) :: cast_ret
+  @spec cast(t, term, options) :: cast_ret | any
     when options: [make_map: boolean]
 
   def cast({:array, type}, term, opts) when is_list(term) do
@@ -152,7 +152,7 @@ defmodule Construct.Type do
   @doc """
   Behaves like `cast/3`, but without options provided to nested types.
   """
-  @spec cast(t, term) :: cast_ret
+  @spec cast(t, term) :: cast_ret | any
 
   def cast(type, term)
 
@@ -336,10 +336,7 @@ defmodule Construct.Type do
   defp cast_naive_datetime(%{} = map) do
     with {:ok, date} <- cast_date(map),
          {:ok, time} <- cast_time(map) do
-      case NaiveDateTime.new(date, time) do
-        {:ok, _} = ok -> ok
-        {:error, _} -> :error
-      end
+      NaiveDateTime.new(date, time)
     end
   end
   defp cast_naive_datetime(_) do
@@ -377,6 +374,172 @@ defmodule Construct.Type do
     end
   end
 
+  ## Typespecs
+
+  @doc """
+  Returns typespec AST for given type
+
+    iex> spec([CommaList, {:array, :integer}]) |> Macro.to_string()
+    "list(:integer)"
+
+    iex> spec({:array, :string}) |> Macro.to_string()
+    "list(String.t())"
+
+    iex> spec({:map, CustomType}) |> Macro.to_string()
+    "%{optional(term) => CustomType.t()}"
+
+    iex> spec(:string) |> Macro.to_string()
+    "String.t()"
+
+    iex> spec(CustomType) |> Macro.to_string()
+    "CustomType.t()"
+  """
+  @spec spec(t) :: Macro.t()
+
+  def spec(type) when is_list(type) do
+    type |> List.last() |> spec()
+  end
+
+  def spec({:array, type}) do
+    quote do
+      list(unquote(spec(type)))
+    end
+  end
+
+  def spec({:map, type}) do
+    quote do
+      %{optional(term) => unquote(spec(type))}
+    end
+  end
+
+  def spec(:string) do
+    quote do
+      String.t()
+    end
+  end
+
+  def spec(:decimal) do
+    quote do
+      Decimal.t()
+    end
+  end
+
+  def spec(:utc_datetime) do
+    quote do
+      DateTime.t()
+    end
+  end
+
+  def spec(:naive_datetime) do
+    quote do
+      NaiveDateTime.t()
+    end
+  end
+
+  def spec(:date) do
+    quote do
+      Date.t()
+    end
+  end
+
+  def spec(:time) do
+    quote do
+      Time.t()
+    end
+  end
+
+  def spec(type) when type in @builtin do
+    type
+  end
+
+  def spec(type) when is_atom(type) do
+    quote do
+      unquote(type).t()
+    end
+  end
+
+  def spec(type) do
+    type
+  end
+
+  @doc """
+  Returns typespec AST for given term
+
+    iex> typeof(nil) |> Macro.to_string()
+    "nil"
+
+    iex> typeof(1.42) |> Macro.to_string()
+    "float()"
+
+    iex> typeof("string") |> Macro.to_string()
+    "String.t()"
+
+    iex> typeof(CustomType) |> Macro.to_string()
+    "CustomType.t()"
+
+    iex> typeof(&NaiveDateTime.utc_now/0) |> Macro.to_string()
+    "NaiveDateTime.t()"
+  """
+  @spec spec(t) :: Macro.t()
+
+  def typeof(term) when is_nil(term) do
+    nil
+  end
+
+  def typeof(term) when is_integer(term) do
+    {:integer, [], []}
+  end
+
+  def typeof(term) when is_float(term) do
+    {:float, [], []}
+  end
+
+  def typeof(term) when is_boolean(term) do
+    {:boolean, [], []}
+  end
+
+  def typeof(term) when is_binary(term) do
+    quote do
+      String.t()
+    end
+  end
+
+  def typeof(term) when is_pid(term) do
+    {:pid, [], []}
+  end
+
+  def typeof(term) when is_reference(term) do
+    {:reference, [], []}
+  end
+
+  def typeof(%{__struct__: struct}) when is_atom(struct) do
+    quote do
+      unquote(struct).t()
+    end
+  end
+
+  def typeof(term) when is_map(term) do
+    {:map, [], []}
+  end
+
+  def typeof(term) when is_atom(term) do
+    quote do
+      unquote(term).t()
+    end
+  end
+
+  def typeof(term) when is_list(term) do
+    {:list, [], []}
+  end
+
+  def typeof(term) when is_function(term, 0) do
+    term.() |> typeof()
+  end
+
+  def typeof(_) do
+    {:term, [], []}
+  end
+
   ## Helpers
 
   defp validate_decimal({:ok, %{__struct__: Decimal, coef: coef}}) when coef in [:inf, :qNaN, :sNaN],
@@ -422,8 +585,6 @@ defmodule Construct.Type do
     {:ok, acc}
   end
 
-  defp map(_, _, _, _, _), do: :error
-
   defp to_i(nil), do: nil
   defp to_i(int) when is_integer(int), do: int
   defp to_i(bin) when is_binary(bin) do

mix.exs

@@ -8,6 +8,9 @@ defmodule Construct.Mixfile do
       elixir: "~> 1.4",
       deps: deps(),
       elixirc_paths: elixirc_paths(Mix.env),
+      dialyzer: [
+        plt_file: {:no_warn, "priv/dialyzer.plt"}
+      ],
 
       # Hex
       description: description(),
@@ -32,6 +35,7 @@ defmodule Construct.Mixfile do
     [
       {:decimal, "~> 1.5", only: [:dev, :test]},
       {:benchfella, "~> 0.3", only: [:dev, :test]},
+      {:dialyxir, "~> 1.0.0-rc.7", only: [:dev, :test], runtime: false},
       {:earmark, "~> 1.2", only: :dev},
       {:ex_doc, "~> 0.19", only: :dev},
       {:jason, "~> 1.1", only: :test}

mix.lock

@@ -1,7 +1,9 @@
 %{
   "benchfella": {:hex, :benchfella, "0.3.5", "b2122c234117b3f91ed7b43b6e915e19e1ab216971154acd0a80ce0e9b8c05f5", [:mix], [], "hexpm"},
   "decimal": {:hex, :decimal, "1.5.0", "b0433a36d0e2430e3d50291b1c65f53c37d56f83665b43d79963684865beab68", [:mix], [], "hexpm"},
+  "dialyxir": {:hex, :dialyxir, "1.0.0-rc.7", "6287f8f2cb45df8584317a4be1075b8c9b8a69de8eeb82b4d9e6c761cf2664cd", [:mix], [{:erlex, ">= 0.2.5", [hex: :erlex, repo: "hexpm", optional: false]}], "hexpm"},
   "earmark": {:hex, :earmark, "1.2.6", "b6da42b3831458d3ecc57314dff3051b080b9b2be88c2e5aa41cd642a5b044ed", [:mix], [], "hexpm"},
+  "erlex": {:hex, :erlex, "0.2.5", "e51132f2f472e13d606d808f0574508eeea2030d487fc002b46ad97e738b0510", [:mix], [], "hexpm"},
   "ex_doc": {:hex, :ex_doc, "0.19.1", "519bb9c19526ca51d326c060cb1778d4a9056b190086a8c6c115828eaccea6cf", [:mix], [{:earmark, "~> 1.1", [hex: :earmark, repo: "hexpm", optional: false]}, {:makeup_elixir, "~> 0.7", [hex: :makeup_elixir, repo: "hexpm", optional: false]}], "hexpm"},
   "jason": {:hex, :jason, "1.1.2", "b03dedea67a99223a2eaf9f1264ce37154564de899fd3d8b9a21b1a6fd64afe7", [:mix], [{:decimal, "~> 1.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm"},
   "makeup": {:hex, :makeup, "0.5.5", "9e08dfc45280c5684d771ad58159f718a7b5788596099bdfb0284597d368a882", [:mix], [{:nimble_parsec, "~> 0.4", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm"},