small improvements, README and example

.gitignore

@@ -10,3 +10,5 @@ cabal-dev
 cabal.sandbox.config
 *~
 .stack-work
+*.dyn_o
+*.dyn_hi

README.md

@@ -9,8 +9,6 @@ Elm Bridge
 
 Hackage: [elm-bridge](http://hackage.haskell.org/package/elm-bridge)
 
- **WARNING: Work in progress!**
-
 Building the bridge from [Haskell](http://haskell.org) to [Elm](http://elm-lang.org) and back. Define types once, use on both sides and enjoy easy (de)serialisation. Cheers!
 
 ## Usage
@@ -18,8 +16,7 @@ Building the bridge from [Haskell](http://haskell.org) to [Elm](http://elm-lang.
 ```haskell
 {-# LANGUAGE TemplateHaskell #-}
 import Elm.Derive
-import Elm.TyRender
-import Elm.TyRep
+import Elm.Module
 
 import Data.Proxy
 
@@ -29,18 +26,41 @@ data Foo
    , f_blablub :: Int
    } deriving (Show, Eq)
 
+deriveElmDef defaultOpts ''Foo
+
 main :: IO ()
 main =
-    putStrLn $ renderElm $ compileElmDef (Proxy :: Proxy Foo)
+    putStrLn $ makeElmModule "Foo"
+    [ DefineElm (Proxy :: Proxy Foo)
+    ]
+
 ```
 
 Output will be:
 
 ```elm
-type alias Foo =
-	{ f_name: String
-	, f_blablub: Int
-	}
+module Foo where
+
+import Json.Decode
+import Json.Decode exposing ((:=))
+import Json.Encode
+
+
+type alias Foo  =
+   { f_name: String
+   , f_blablub: Int
+   }
+
+jsonDecFoo  =
+   ("f_name" := Json.Decode.string) `Json.Decode.andThen` \pf_name ->
+   ("f_blablub" := Json.Decode.int) `Json.Decode.andThen` \pf_blablub ->
+   Json.Decode.succeed {f_name = pf_name, f_blablub = pf_blablub}
+
+jsonEncFoo  val =
+   Json.Encode.object
+   [ ("f_name", Json.Encode.string val.f_name)
+   , ("f_blablub", Json.Encode.int val.f_blablub)
+   ]
 ```
 
 For more usage examples check the tests.
@@ -49,7 +69,3 @@ For more usage examples check the tests.
 
 * Using cabal: `cabal install elm-bridge`
 * From Source: `git clone https://github.com/agrafix/elm-bridge.git && cd elm-bridge && cabal install`
-
-## Todo
-
-* Generate Elm JSON Serializer/Parser

elm-bridge.cabal

@@ -15,6 +15,7 @@ cabal-version:       >=1.10
 
 extra-source-files:
     README.md
+    examples/*.hs
 
 library
   hs-source-dirs:      src

examples/Example1.hs

@@ -0,0 +1,20 @@
+{-# LANGUAGE PackageImports #-}
+{-# LANGUAGE TemplateHaskell #-}
+import "elm-bridge" Elm.Derive
+import "elm-bridge" Elm.Module
+
+import Data.Proxy
+
+data Foo
+   = Foo
+   { f_name :: String
+   , f_blablub :: Int
+   } deriving (Show, Eq)
+
+deriveElmDef defaultOpts ''Foo
+
+main :: IO ()
+main =
+    putStrLn $ makeElmModule "Foo"
+    [ DefineElm (Proxy :: Proxy Foo)
+    ]

src/Elm/Json.hs

@@ -1,3 +1,7 @@
+{- |
+This module implements a generator for JSON serialisers and parsers of arbitrary elm types.
+Please note: It's still very hacky and might not work for all possible elm types yet.
+-}
 module Elm.Json
     ( jsonParserForDef
     , jsonSerForDef
@@ -9,6 +13,7 @@ import Data.Maybe
 
 import Elm.TyRep
 
+-- | Compile a JSON parser for an Elm type
 jsonParserForType :: EType -> String
 jsonParserForType ty =
     case ty of
@@ -39,6 +44,7 @@ jsonParserForType ty =
                 in "Json.Decode.tuple" ++ show tupleLen ++ " (" ++ commas ++ ") "
                     ++ unwords (map (\t' -> "(" ++ jsonParserForType t' ++ ")") xs)
 
+-- | Compile a JSON parser for an Elm type definition
 jsonParserForDef :: ETypeDef -> String
 jsonParserForDef etd =
     case etd of
@@ -66,7 +72,7 @@ jsonParserForDef etd =
            "jsonDec" ++ et_name name ++ " "
            ++ unwords (map (\tv -> "localDecoder_" ++ tv_name tv) $ et_args name)
 
-
+-- | Compile a JSON serializer for an Elm type
 jsonSerForType :: EType -> String
 jsonSerForType ty =
     case ty of
@@ -98,7 +104,7 @@ jsonSerForType ty =
                         unwords $ map (\(_, v) -> "v" ++ show v) tupleArgsV
                 in "(\\" ++ tupleArgs ++ " -> [" ++  intercalate "," (map (\(t', idx) -> "(" ++ jsonSerForType t' ++ ") v" ++ show idx) tupleArgsV) ++ "]"
 
-
+-- | Compile a JSON serializer for an Elm type definition
 jsonSerForDef :: ETypeDef -> String
 jsonSerForDef etd =
     case etd of

src/Elm/Module.hs

@@ -9,12 +9,18 @@ import Elm.TyRep
 import Elm.TyRender
 import Elm.Json
 
+-- | Existential quantification wrapper for lists of type definitions
 data DefineElm
    = forall a. IsElmDefinition a => DefineElm (Proxy a)
 
+-- | Compile an Elm module
 makeElmModule :: String -> [DefineElm] -> String
 makeElmModule moduleName defs =
-    "module " ++ moduleName ++ " where \n"
+    "module " ++ moduleName ++ " where \n\n"
+    ++ "import Json.Decode\n"
+    ++ "import Json.Decode exposing ((:=))\n"
+    ++ "import Json.Encode\n"
+    ++ "\n\n"
     ++ intercalate "\n\n" (map mkDef defs)
     where
       mkDef (DefineElm proxy) =

src/Elm/TyRender.hs

@@ -40,7 +40,7 @@ instance ElmRenderable ETypeName where
 instance ElmRenderable EAlias where
     renderElm alias =
         "type alias " ++ renderElm (ea_name alias) ++ " = \n   { "
-        ++ intercalate "\n,    " (map (\(fld, ty) -> fld ++ ": " ++ renderElm ty) (ea_fields alias))
+        ++ intercalate "\n   , " (map (\(fld, ty) -> fld ++ ": " ++ renderElm ty) (ea_fields alias))
         ++ "\n   }\n"
 
 instance ElmRenderable ESum where

test/Elm/ModuleSpec.hs

@@ -20,7 +20,7 @@ data Bar a
 $(deriveElmDef (fieldDropOpts 2) ''Bar)
 
 moduleCode :: String
-moduleCode = "module Foo where \ntype alias Bar a = \n   { name: a\n,    blablub: Int\n,    tuple: (Int, String)\n,    list: (List Bool)\n   }\n\njsonDecBar localDecoder_a = \n   (\"name\" := localDecoder_a) `Json.Decode.andThen` \\pname -> \n   (\"blablub\" := Json.Decode.int) `Json.Decode.andThen` \\pblablub -> \n   (\"tuple\" := Json.Decode.tuple2 (,) (Json.Decode.int) (Json.Decode.string)) `Json.Decode.andThen` \\ptuple -> \n   (\"list\" := Json.Decode.list (Json.Decode.bool)) `Json.Decode.andThen` \\plist -> \n   Json.Decode.succeed {name = pname, blablub = pblablub, tuple = ptuple, list = plist}\n\njsonEncBar localEncoder_a val = \n   Json.Encode.object\n   [ (\"name\", localEncoder_a val.name)\n   , (\"blablub\", Json.Encode.int val.blablub)\n   , (\"tuple\", (\\v1 v2 -> [(Json.Encode.int) v1,(Json.Encode.string) v2] val.tuple)\n   , (\"list\", (Json.Encode.list << map Json.Encode.bool) val.list)\n   ]\n\n"
+moduleCode = "module Foo where \n\nimport Json.Decode\nimport Json.Decode exposing ((:=))\nimport Json.Encode\n\n\ntype alias Bar a = \n   { name: a\n   , blablub: Int\n   , tuple: (Int, String)\n   , list: (List Bool)\n   }\n\njsonDecBar localDecoder_a = \n   (\"name\" := localDecoder_a) `Json.Decode.andThen` \\pname -> \n   (\"blablub\" := Json.Decode.int) `Json.Decode.andThen` \\pblablub -> \n   (\"tuple\" := Json.Decode.tuple2 (,) (Json.Decode.int) (Json.Decode.string)) `Json.Decode.andThen` \\ptuple -> \n   (\"list\" := Json.Decode.list (Json.Decode.bool)) `Json.Decode.andThen` \\plist -> \n   Json.Decode.succeed {name = pname, blablub = pblablub, tuple = ptuple, list = plist}\n\njsonEncBar localEncoder_a val = \n   Json.Encode.object\n   [ (\"name\", localEncoder_a val.name)\n   , (\"blablub\", Json.Encode.int val.blablub)\n   , (\"tuple\", (\\v1 v2 -> [(Json.Encode.int) v1,(Json.Encode.string) v2] val.tuple)\n   , (\"list\", (Json.Encode.list << map Json.Encode.bool) val.list)\n   ]\n\n"
 
 spec :: Spec
 spec =

test/Elm/TyRenderSpec.hs

@@ -33,10 +33,10 @@ $(deriveElmDef (fieldDropOpts 2) ''Bar)
 $(deriveElmDef defaultOpts ''SomeOpts)
 
 fooCode :: String
-fooCode = "type alias Foo  = \n   { name: String\n,    blablub: Int\n   }\n"
+fooCode = "type alias Foo  = \n   { name: String\n   , blablub: Int\n   }\n"
 
 barCode :: String
-barCode = "type alias Bar a = \n   { name: a\n,    blablub: Int\n,    tuple: (Int, String)\n,    list: (List Bool)\n   }\n"
+barCode = "type alias Bar a = \n   { name: a\n   , blablub: Int\n   , tuple: (Int, String)\n   , list: (List Bool)\n   }\n"
 
 someOptsCode :: String
 someOptsCode = "type SomeOpts a = \n    Okay Int\n    | NotOkay a\n"