Fixes issue with printing correct pipeline when parsing optional enum/union types

Author: dragonwasrobot

examples/example-input-json-schemas/circle.json

@@ -14,5 +14,6 @@
         "color": {
             "$ref": "http://example.com/definitions.json#color"
         }
-    }
+    },
+    "required": ["center", "radius"]
 }

lib/printers/object_printer.ex

@@ -164,35 +164,44 @@ defmodule JS2E.Printers.ObjectPrinter do
 
     decoder_name = print_decoder_name(property_type)
 
+    is_required = property_name in required
+
     cond do
-      union_type?(property_type) ->
-        print_custom_clause(property_name, decoder_name)
+      union_type?(property_type) || one_of_type?(property_type) ->
+        print_union_clause(property_name, decoder_name, is_required)
+
+      enum_type?(property_type) ->
+        property_type_decoder =
+          property_type.type
+          |> determine_primitive_type_decoder()
 
-      property_name in required ->
-        print_required_clause(property_name, decoder_name)
+        print_enum_clause(property_name, property_type_decoder,
+          decoder_name, is_required)
 
       true ->
-        print_optional_clause(property_name, decoder_name)
+        print_normal_clause(property_name, decoder_name, is_required)
     end
   end
 
-  @spec print_decoder_name(Types.typeDefinition) :: String.t
-  defp print_decoder_name(property_type) do
+  @spec determine_primitive_type_decoder(String.t) :: String.t
+  defp determine_primitive_type_decoder(property_type_value) do
+    case property_type_value do
+      "integer" ->
+        "int"
 
-    if primitive_type?(property_type) do
-      property_type_value = property_type.type
-
-      case property_type_value do
-        "integer" ->
-          "int"
+      "number" ->
+        "float"
 
-        "number" ->
-          "float"
+      _ ->
+        property_type_value
+    end
+  end
 
-        _ ->
-          property_type_value
-      end
+  @spec print_decoder_name(Types.typeDefinition) :: String.t
+  defp print_decoder_name(property_type) do
 
+    if primitive_type?(property_type) do
+      determine_primitive_type_decoder(property_type.type)
     else
 
       property_type_name = property_type.name
@@ -209,26 +218,62 @@ defmodule JS2E.Printers.ObjectPrinter do
     Util.get_string_name(type) == "PrimitiveType"
   end
 
+  defp enum_type?(type) do
+    Util.get_string_name(type) == "EnumType"
+  end
+
+  defp one_of_type?(type) do
+    Util.get_string_name(type) == "OneOfType"
+  end
+
   defp union_type?(type) do
     Util.get_string_name(type) == "UnionType"
   end
 
-  defp print_custom_clause(property_name, decoder_name) do
+  defp print_union_clause(property_name, decoder_name, is_required) do
     double_indent = Util.indent(2)
-    "#{double_indent}|> " <>
-      "custom (field \"#{property_name}\" #{decoder_name})"
+
+    if is_required do
+      "#{double_indent}|> " <>
+        "required \"#{property_name}\" #{decoder_name}"
+
+    else
+      "#{double_indent}|> " <>
+        "optional \"#{property_name}\" (nullable #{decoder_name}) Nothing"
+    end
   end
 
-  defp print_required_clause(property_name, decoder_name) do
+  defp print_enum_clause(
+    property_name,
+    property_type_decoder,
+    decoder_name,
+    is_required) do
+
     double_indent = Util.indent(2)
-    "#{double_indent}|> " <>
-      "required \"#{property_name}\" #{decoder_name}"
+
+    if is_required do
+      "#{double_indent}|> " <>
+        "required \"#{property_name}\" (#{property_type_decoder} |> " <>
+        "andThen #{decoder_name})"
+
+    else
+      "#{double_indent}|> " <>
+        "optional \"#{property_name}\" (#{property_type_decoder} |> " <>
+        "andThen #{decoder_name} |> maybe) Nothing"
+    end
   end
 
-  defp print_optional_clause(property_name, decoder_name) do
+  defp print_normal_clause(property_name, decoder_name, is_required) do
     double_indent = Util.indent(2)
-    "#{double_indent}|> " <>
-      "optional \"#{property_name}\" (nullable #{decoder_name}) Nothing"
+
+    if is_required do
+      "#{double_indent}|> " <>
+        "required \"#{property_name}\" #{decoder_name}"
+
+    else
+      "#{double_indent}|> " <>
+        "optional \"#{property_name}\" (nullable #{decoder_name}) Nothing"
+    end
   end
 
 end

lib/printers/preamble_printer.ex

@@ -31,11 +31,13 @@ defmodule JS2E.Printers.PreamblePrinter do
     import Json.Decode as Decode
         exposing
             ( int
+            , float
             , string
             , succeed
             , fail
             , list
             , map
+            , maybe
             , field
             , at
             , andThen

lib/types/enum_type.ex

@@ -59,7 +59,7 @@ defmodule JS2E.Types.EnumType do
 
   - Usage
 
-      |> custom (field "color" string |> andThen colorDecoder)
+      |> required "color" (string |> andThen colorDecoder)
 
   """
 

lib/types/one_of_type.ex

@@ -43,7 +43,7 @@ defmodule JS2E.Types.OneOfType do
 
   - Usage
 
-  |> custom (field "shape" shapeDecoder)
+  |> required "shape" shapeDecoder
 
   """
 

lib/types/union_type.ex

@@ -34,7 +34,7 @@ defmodule JS2E.Types.UnionType do
 
   - Usage
 
-      |> custom (field "favoriteNumber" favoriteNumberDecoder)
+    |> required "favoriteNumber" favoriteNumberDecoder
 
   """
 

mix.exs

@@ -6,6 +6,10 @@ defmodule JS2.Mixfile do
      version: "1.0.0",
      elixir: "~> 1.4",
      deps: deps(),
+     build_embedded: Mix.env == :prod,
+     start_permanent: Mix.env == :prod,
+
+     # Dialyxir
      dialyzer: [plt_add_deps: :project],
 
      # Docs

test/printers/external_references_test.exs

@@ -117,11 +117,13 @@ defmodule JS2ETest.Printers.ExternalReferences do
       import Json.Decode as Decode
           exposing
               ( int
+              , float
               , string
               , succeed
               , fail
               , list
               , map
+              , maybe
               , field
               , at
               , andThen
@@ -156,7 +158,7 @@ defmodule JS2ETest.Printers.ExternalReferences do
       circleDecoder =
           decode Circle
               |> optional "center" (nullable pointDecoder) Nothing
-              |> optional "color" (nullable colorDecoder) Nothing
+              |> optional "color" (string |> andThen colorDecoder |> maybe) Nothing
               |> optional "radius" (nullable float) Nothing
       """
 
@@ -172,11 +174,13 @@ defmodule JS2ETest.Printers.ExternalReferences do
       import Json.Decode as Decode
           exposing
               ( int
+              , float
               , string
               , succeed
               , fail
               , list
               , map
+              , maybe
               , field
               , at
               , andThen

test/printers/object_printer_test.exs

@@ -86,7 +86,7 @@ defmodule JS2ETest.Printers.ObjectPrinter do
     circleDecoder : Decoder Circle
     circleDecoder =
         decode Circle
-            |> required "color" colorDecoder
+            |> required "color" (string |> andThen colorDecoder)
             |> required "radius" float
             |> optional "title" (nullable string) Nothing
     """