Allow keywords in typespecs

Author: José Valim

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 * enhancements
   * [Kernel] Add `String.start_with?` and `String.end_with?`
+  * [Typespec] Allow keywords, e.g. `[foo: integer, bar: boolean | module]`, in typespecs
 
 * bug fix
   * [Dict] `Enum.to_list` and `Dict.to_list` now return the same results for dicts

lib/elixir/lib/kernel/typespec.ex

@@ -422,6 +422,17 @@ defmodule Kernel.Typespec do
     { :{}, [line: line], args }
   end
 
+  defp typespec_to_ast({ :type, _line, :list, [arg] }) do
+    case unpack_typespec_kw(arg, []) do
+      { :ok, ast } -> ast
+      :error -> [typespec_to_ast(arg)]
+    end
+  end
+
+  defp typespec_to_ast({ :type, _line, :list, args }) do
+    lc arg inlist args, do: typespec_to_ast(arg)
+  end
+
   defp typespec_to_ast({ :type, line, :binary, [arg1, arg2] }) do
     [arg1, arg2] = lc arg inlist [arg1, arg2], do: typespec_to_ast(arg)
     cond do
@@ -473,7 +484,7 @@ defmodule Kernel.Typespec do
     { var, line, nil }
   end
 
-  # special shortcut(s)
+  # Special shortcut(s)
   defp typespec_to_ast({ :remote_type, line, [{:atom, _, :elixir}, {:atom, _, :char_list}, []] }) do
     typespec_to_ast({:type, line, :char_list, []})
   end
@@ -482,7 +493,6 @@ defmodule Kernel.Typespec do
     typespec_to_ast({:type, line, :as_boolean, [arg]})
   end
 
-
   defp typespec_to_ast({ :remote_type, line, [mod, name, args] }) do
     args = lc arg inlist args, do: typespec_to_ast(arg)
     dot  = { :., [line: line], [typespec_to_ast(mod), typespec_to_ast(name)] }
@@ -524,7 +534,7 @@ defmodule Kernel.Typespec do
 
   # Handle unions
   defp typespec({ :|, meta, [_,_] } = exprs, vars, caller) do
-    exprs = :lists.reverse(collect_union(exprs))
+    exprs = Enum.reverse(collect_union(exprs))
     union = lc e inlist exprs, do: typespec(e, vars, caller)
     { :type, line(meta), :union, union }
   end
@@ -558,7 +568,6 @@ defmodule Kernel.Typespec do
   end
 
   # Handle funs
-
   defp typespec({:->, meta, [{[{:fun, _, arguments}], return}]}, vars, caller) when is_list(arguments) do
     typespec({:->, meta, [{arguments, return}]}, vars, caller)
   end
@@ -609,7 +618,6 @@ defmodule Kernel.Typespec do
   end
 
   # Handle blocks
-
   defp typespec({:__block__, _meta, [arg]}, vars, caller) do
     typespec(arg, vars, caller)
   end
@@ -665,8 +673,11 @@ defmodule Kernel.Typespec do
     typespec({ :nonempty_list, [], [spec] }, vars, caller)
   end
 
-  defp typespec(l, _, _) when is_list(l) do
-    raise ArgumentError, message: "Unexpected list #{inspect l}"
+  defp typespec([h|t] = l, vars, caller) do
+    union = Enum.reduce(t, validate_kw(h, l), fn(x, acc) ->
+      { :|, [], [acc, validate_kw(x, l)] }
+    end)
+    typespec({ :list, [], [union] }, vars, caller)
   end
 
   defp typespec(t, vars, caller) when is_tuple(t) do
@@ -684,6 +695,11 @@ defmodule Kernel.Typespec do
   defp collect_union({ :|, _, [a, b] }), do: [b|collect_union(a)]
   defp collect_union(v), do: [v]
 
+  defp validate_kw({ key, _ } = t, _) when is_atom(key), do: t
+  defp validate_kw(_, original) do
+    raise ArgumentError, message: "unexpected list #{inspect original} in typespec"
+  end
+
   defp fn_args(meta, args, return, vars, caller) do
     case [fn_args(meta, args, vars, caller), typespec(return, vars, caller)] do
       [{:type,_,:any},{:type,_,:any,[]}] -> []
@@ -703,4 +719,19 @@ defmodule Kernel.Typespec do
   defp variable({name, meta, _}) do
     {:var, line(meta), name}
   end
+
+  defp unpack_typespec_kw({ :type, _, :union, [
+         next,
+         { :type, _, :tuple, [{ :atom, _, atom }, type] }
+       ] }, acc) do
+    unpack_typespec_kw(next, [{atom,typespec_to_ast(type)}|acc])
+  end
+
+  defp unpack_typespec_kw({ :type, _, :tuple, [{ :atom, _, atom }, type] }, acc) do
+    { :ok, [{atom,typespec_to_ast(type)}|acc] }
+  end
+
+  defp unpack_typespec_kw(_, _acc) do
+    :error
+  end
 end

lib/elixir/test/elixir/typespec_test.exs

@@ -214,6 +214,18 @@ defmodule Typespec.TypeTest do
              [{:atom, _, Range}, {:type, _, :integer, []}, {:type, _, :any, []}]}, []} = spec
   end
 
+  test "@type with keywords" do
+    spec = test_module do
+      @type mytype :: [first: integer, last: integer]
+    end
+    assert {:mytype,{:type,_,:list,[
+      {:type,_,:union,[
+        {:type,_,:tuple,[{:atom,_,:first},{:type,_,:integer,[]}]},
+        {:type,_,:tuple,[{:atom,_,:last},{:type,_,:integer,[]}]}
+      ]}
+    ]}, []} = spec
+  end
+
   test "@type with parameters" do
     {spec1, spec2, spec3} = test_module do
       t1 = @type mytype(x) :: x
@@ -339,7 +351,7 @@ defmodule Typespec.TypeTest do
       (quote do: @type imm_type_1() :: 1),
       (quote do: @type imm_type_2() :: :atom),
       (quote do: @type simple_type() :: integer()),
-      (quote do: @type param_type(p) :: list(p)),
+      (quote do: @type param_type(p) :: [p]),
       (quote do: @type union_type() :: integer() | binary() | boolean()),
       (quote do: @type binary_type1() :: <<_ :: _ * 8>>),
       (quote do: @type binary_type2() :: <<_ :: 3 * 8>>),
@@ -350,6 +362,7 @@ defmodule Typespec.TypeTest do
       (quote do: @type ab() :: as_boolean(term())),
       (quote do: @type vaf() :: (... -> any())),
       (quote do: @type rng() :: 1 .. 10),
+      (quote do: @type opts() :: [first: integer(), last: integer()]),
     ]
 
     types = test_module do