Add API for combining form parsers into a type without the input type variable.

examples/todos/app/Route/Login.elm

@@ -12,7 +12,7 @@ import ErrorPage exposing (ErrorPage)
 import Form
 import Form.Field as Field
 import Form.FieldView
-import Form.Validation as Validation exposing (Combined, Field)
+import Form.Validation as Validation exposing (Combined, Field, Validation)
 import Head
 import Head.Seo as Seo
 import Html exposing (Html)
@@ -100,7 +100,7 @@ type alias EnvVariables =
     }
 
 
-form : Form.DoneForm String (DataSource (Combined String Action)) data (List (Html (Pages.Msg.Msg Msg)))
+form : Form.DoneForm String (DataSource (Combined String EmailAddress)) data (List (Html (Pages.Msg.Msg Msg)))
 form =
     Form.init
         (\fieldEmail ->
@@ -117,7 +117,7 @@ form =
                                 (\emailSendResult ->
                                     case emailSendResult of
                                         Ok () ->
-                                            Validation.succeed (LI email)
+                                            Validation.succeed email
 
                                         Err error ->
                                             Validation.fail "Whoops, something went wrong sending an email to that address. Try again?" Validation.global
@@ -146,11 +146,11 @@ form =
         |> Form.hiddenKind ( "kind", "login" ) "Expected kind"
 
 
-logoutForm : Form.DoneForm String Action data (List (Html (Pages.Msg.Msg Msg)))
+logoutForm : Form.DoneForm String () data (List (Html (Pages.Msg.Msg Msg)))
 logoutForm =
     Form.init
         { combine =
-            Validation.succeed Logout
+            Validation.succeed ()
         , view =
             \info ->
                 [ Html.button []
@@ -297,15 +297,20 @@ data routeParams =
         )
 
 
+allForms : Form.ServerForms String (DataSource (Combined String Action))
+allForms =
+    logoutForm
+        |> Form.toServerForm
+        |> Form.initCombinedServer (\_ -> Logout)
+        |> Form.combineServer LI form
+
+
 action : RouteParams -> Request.Parser (DataSource (Response ActionData ErrorPage))
 action routeParams =
     MySession.withSession
         (Request.map2 Tuple.pair
             (Request.oneOf
-                [ Request.formDataWithServerValidation
-                    [ logoutForm |> Form.toServerForm
-                    , form
-                    ]
+                [ Request.formDataWithServerValidation allForms
                 ]
             )
             Request.requestTime

examples/todos/app/Route/Visibility__.elm

@@ -477,14 +477,13 @@ view maybeUrl sharedModel model app =
     }
 
 
-newItemForm : Form.HtmlForm String Action input Msg
+newItemForm : Form.HtmlForm String String input Msg
 newItemForm =
     Form.init
         (\description ->
             { combine =
                 Validation.succeed identity
                     |> Validation.andMap description
-                    |> Validation.map Add
             , view =
                 \formState ->
                     [ header
@@ -505,9 +504,15 @@ newItemForm =
         |> Form.hiddenKind ( "kind", "new-item" ) "Expected kind"
 
 
-allForms : List (Form.HtmlForm String Action Todo Msg)
+allForms : Form.ServerForms String Action
 allForms =
-    [ editItemForm, newItemForm, completeItemForm, deleteItemForm, clearCompletedForm, toggleAllForm ]
+    editItemForm
+        |> Form.initCombined UpdateEntry
+        |> Form.combine Add newItemForm
+        |> Form.combine Check completeItemForm
+        |> Form.combine Delete deleteItemForm
+        |> Form.combine (\_ -> DeleteComplete) clearCompletedForm
+        |> Form.combine CheckAll toggleAllForm
 
 
 
@@ -554,12 +559,12 @@ viewEntries app visibility entries =
         ]
 
 
-toggleAllForm : Form.HtmlForm String Action input Msg
+toggleAllForm : Form.HtmlForm String Bool input Msg
 toggleAllForm =
     Form.init
         (\toggleTo ->
             { combine =
-                Validation.succeed CheckAll
+                Validation.succeed identity
                     |> Validation.andMap toggleTo
             , view =
                 \formState ->
@@ -633,7 +638,7 @@ viewEntry app todo =
         ]
 
 
-completeItemForm : Form.HtmlForm String Action Todo Msg
+completeItemForm : Form.HtmlForm String ( Bool, String ) Todo Msg
 completeItemForm =
     Form.init
         (\todoId complete ->
@@ -641,7 +646,6 @@ completeItemForm =
                 Validation.succeed Tuple.pair
                     |> Validation.andMap complete
                     |> Validation.andMap todoId
-                    |> Validation.map Check
             , view =
                 \formState ->
                     [ Html.button [ class "toggle" ]
@@ -666,7 +670,7 @@ completeItemForm =
         |> Form.hiddenKind ( "kind", "complete" ) "Expected kind"
 
 
-editItemForm : Form.HtmlForm String Action Todo Msg
+editItemForm : Form.HtmlForm String ( String, String ) Todo Msg
 editItemForm =
     Form.init
         (\itemId description ->
@@ -674,7 +678,6 @@ editItemForm =
                 Validation.succeed Tuple.pair
                     |> Validation.andMap itemId
                     |> Validation.andMap description
-                    |> Validation.map UpdateEntry
             , view =
                 \formState ->
                     [ FieldView.input
@@ -700,12 +703,12 @@ editItemForm =
         |> Form.hiddenKind ( "kind", "edit-item" ) "Expected kind"
 
 
-deleteItemForm : Form.HtmlForm String Action Todo Msg
+deleteItemForm : Form.HtmlForm String String Todo Msg
 deleteItemForm =
     Form.init
         (\todoId ->
             { combine =
-                Validation.succeed Delete
+                Validation.succeed identity
                     |> Validation.andMap todoId
             , view =
                 \formState ->
@@ -807,10 +810,10 @@ visibilitySwap visibilityParam visibility actualVisibility =
         ]
 
 
-clearCompletedForm : Form.HtmlForm String Action input Msg
+clearCompletedForm : Form.HtmlForm String () input Msg
 clearCompletedForm =
     Form.init
-        { combine = Validation.succeed DeleteComplete
+        { combine = Validation.succeed ()
         , view =
             \formState ->
                 [ button

src/Form.elm

@@ -11,7 +11,13 @@ module Form exposing
     , dynamic
     , AppContext
     , toServerForm, withOnSubmit
-    -- subGroup
+    ,  ServerForms(..)
+       -- subGroup
+      , combine
+      , combineServer
+      , initCombined
+      , initCombinedServer
+
     )
 
 {-| One of the core features of elm-pages is helping you manage form data end-to-end, including
@@ -854,13 +860,13 @@ insertIfNonempty key values dict =
 {-| -}
 runServerSide :
     List ( String, String )
-    -> Form error { all | combine : Validation error parsed kind constraints } data
+    -> Form error (Validation error parsed kind constraints) data
     -> ( Maybe parsed, Dict String (List error) )
 runServerSide rawFormData (Form _ parser _) =
     let
         parsed :
             { result : Dict String (List error)
-            , combineAndView : { all | combine : Validation error parsed kind constraints }
+            , combineAndView : Validation error parsed kind constraints
             }
         parsed =
             parser Nothing thisFormState
@@ -881,7 +887,7 @@ runServerSide rawFormData (Form _ parser _) =
                         |> Dict.fromList
             }
     in
-    { result = ( parsed.combineAndView.combine, parsed.result )
+    { result = ( parsed.combineAndView, parsed.result )
     }
         |> mergeResults
         |> unwrapValidation
@@ -895,15 +901,9 @@ unwrapValidation (Pages.Internal.Form.Validation _ _ ( maybeParsed, errors )) =
 {-| -}
 runOneOfServerSide :
     List ( String, String )
-    ->
-        List
-            (Form
-                error
-                { all | combine : Validation error parsed kind constraints }
-                data
-            )
+    -> ServerForms error parsed
     -> ( Maybe parsed, Dict String (List error) )
-runOneOfServerSide rawFormData parsers =
+runOneOfServerSide rawFormData (ServerForms parsers) =
     case parsers of
         firstParser :: remainingParsers ->
             let
@@ -922,7 +922,7 @@ runOneOfServerSide rawFormData parsers =
                     ( Just parsed, Dict.empty )
 
                 _ ->
-                    runOneOfServerSide rawFormData remainingParsers
+                    runOneOfServerSide rawFormData (ServerForms remainingParsers)
 
         [] ->
             -- TODO need to pass errors
@@ -1422,6 +1422,157 @@ type alias HtmlForm error parsed input msg =
         input
 
 
+{-| -}
+type ServerForms error parsed
+    = ServerForms
+        (List
+            (Form
+                error
+                (Combined error parsed)
+                Never
+            )
+        )
+
+
+{-| -}
+initCombined :
+    (parsed -> combined)
+    ->
+        Form
+            error
+            { combineAndView
+                | combine : Combined error parsed
+            }
+            input
+    -> ServerForms error combined
+initCombined mapFn (Form _ parseFn _) =
+    ServerForms
+        [ Form
+            []
+            (\_ formState ->
+                let
+                    foo :
+                        { result : Dict String (List error)
+                        , combineAndView : { combineAndView | combine : Combined error parsed }
+                        }
+                    foo =
+                        parseFn Nothing formState
+                in
+                { result = foo.result
+                , combineAndView = foo.combineAndView.combine |> Validation.map mapFn
+                }
+            )
+            (\_ -> [])
+        ]
+
+
+{-| -}
+combine :
+    (parsed -> combined)
+    ->
+        Form
+            error
+            { combineAndView
+                | combine : Combined error parsed
+            }
+            input
+    -> ServerForms error combined
+    -> ServerForms error combined
+combine mapFn (Form _ parseFn _) (ServerForms serverForms) =
+    ServerForms
+        (Form []
+            (\_ formState ->
+                let
+                    foo :
+                        { result : Dict String (List error)
+                        , combineAndView : { combineAndView | combine : Combined error parsed }
+                        }
+                    foo =
+                        parseFn Nothing formState
+                in
+                { result = foo.result
+                , combineAndView = foo.combineAndView.combine |> Validation.map mapFn
+                }
+            )
+            (\_ -> [])
+            :: serverForms
+        )
+
+
+{-| -}
+initCombinedServer :
+    (parsed -> combined)
+    ->
+        Form
+            error
+            { combineAndView
+                | combine : Combined error (DataSource (Validation error parsed kind constraints))
+            }
+            input
+    -> ServerForms error (DataSource (Validation error combined kind constraints))
+initCombinedServer mapFn (Form _ parseFn _) =
+    ServerForms
+        [ Form
+            []
+            (\_ formState ->
+                let
+                    --foo :
+                    --    { result : Dict String (List error)
+                    --    , combineAndView : { combineAndView | combine : Combined error parsed }
+                    --    }
+                    foo :
+                        { result : Dict String (List error)
+                        , combineAndView : { combineAndView | combine : Combined error (DataSource (Validation error parsed kind constraints)) }
+                        }
+                    foo =
+                        parseFn Nothing formState
+                in
+                { result = foo.result
+                , combineAndView = foo.combineAndView.combine |> Validation.map (DataSource.map (Validation.map mapFn))
+                }
+            )
+            (\_ -> [])
+        ]
+
+
+{-| -}
+combineServer :
+    (parsed -> combined)
+    ->
+        Form
+            error
+            { combineAndView
+                | combine :
+                    Combined error (DataSource (Validation error parsed kind constraints))
+            }
+            input
+    -> ServerForms error (DataSource (Validation error combined kind constraints))
+    -> ServerForms error (DataSource (Validation error combined kind constraints))
+combineServer mapFn (Form _ parseFn _) (ServerForms serverForms) =
+    ServerForms
+        (Form []
+            (\_ formState ->
+                let
+                    --foo :
+                    --    { result : Dict String (List error)
+                    --    , combineAndView : { combineAndView | combine : Combined error parsed }
+                    --    }
+                    foo :
+                        { result : Dict String (List error)
+                        , combineAndView : { combineAndView | combine : Combined error (DataSource (Validation error parsed kind constraints)) }
+                        }
+                    foo =
+                        parseFn Nothing formState
+                in
+                { result = foo.result
+                , combineAndView = foo.combineAndView.combine |> Validation.map (DataSource.map (Validation.map mapFn))
+                }
+            )
+            (\_ -> [])
+            :: serverForms
+        )
+
+
 {-| -}
 type alias StyledHtmlForm error parsed data msg =
     Form
@@ -1451,17 +1602,17 @@ type FormInternal error parsed data view
 
 
 {-| -}
-type Form error combineAndView data
+type Form error combineAndView input
     = Form
         (List ( String, FieldDefinition ))
-        (Maybe data
+        (Maybe input
          -> FormState
          ->
             { result : Dict String (List error)
             , combineAndView : combineAndView
             }
         )
-        (data -> List ( String, String ))
+        (input -> List ( String, String ))
 
 
 type alias RenderOptions userMsg =

src/Server/Request.elm

@@ -885,12 +885,7 @@ fileField_ name =
 
 {-| -}
 formDataWithServerValidation :
-    List
-        (Form.Form
-            error
-            { all | combine : Validation error (DataSource (Validation error combined kind constraints)) kind constraints }
-            data
-        )
+    Form.ServerForms error (DataSource (Validation error combined kind constraints))
     -> Parser (DataSource (Result (Form.Response error) ( Form.Response error, combined )))
 formDataWithServerValidation formParsers =
     rawFormData
@@ -950,12 +945,7 @@ formDataWithServerValidation formParsers =
 
 {-| -}
 formData :
-    List
-        (Form.Form
-            error
-            { all | combine : Validation error combined kind constraints }
-            data
-        )
+    Form.ServerForms error combined
     -> Parser (Result { fields : List ( String, String ), errors : Dict String (List error) } combined)
 formData formParsers =
     rawFormData