dev: web: simplify types a little (#1229)

hledger-web/Hledger/Web/Foundation.hs

@@ -84,11 +84,12 @@ data App = App
 -- usually require access to the AppRoute datatype. Therefore, we
 -- split these actions into two functions and place them in separate files.
 mkYesodData "App" $(parseRoutesFile "config/routes")
+-- ^ defines things like:
+-- type Handler = HandlerFor App   -- HandlerT App IO, https://www.yesodweb.com/book/routing-and-handlers#routing-and-handlers_handler_monad
+-- type Widget = WidgetFor App ()  -- WidgetT App IO (), https://www.yesodweb.com/book/widgets
 
--- | A convenience alias.
 type AppRoute = Route App
-
+type Form a = Html -> MForm Handler (FormResult a, Widget)
-type Form x = Html -> MForm (HandlerFor App) (FormResult x, Widget)
 
 -- Please see the documentation for the Yesod typeclass. There are a number
 -- of settings which can be configured by overriding methods here.

hledger-web/Hledger/Web/Handler/EditR.hs

@@ -15,7 +15,7 @@ import Hledger.Web.Import
 import Hledger.Web.Widget.Common
        (fromFormSuccess, helplink, journalFile404, writeJournalTextIfValidAndChanged)
 
-editForm :: FilePath -> Text -> Markup -> MForm Handler (FormResult Text, Widget)
+editForm :: FilePath -> Text -> Form Text
 editForm f txt =
   identifyForm "edit" $ \extra -> do
     (tRes, tView) <- mreq textareaField fs (Just (Textarea txt))

hledger-web/Hledger/Web/Widget/AddForm.hs

@@ -25,15 +25,17 @@ import Text.Megaparsec (bundleErrors, eof, parseErrorTextPretty, runParser)
 import Yesod
 
 import Hledger
+import Hledger.Web.Foundation -- (App, Form, Handler, Widget)
 import Hledger.Web.Settings (widgetFile)
 
-addModal ::
+-- addModal ::
-     ( MonadWidget m
+--      ( MonadWidget m
-     , r ~ Route (HandlerSite m)
+--      , r ~ Route (HandlerSite m)
-     , m ~ WidgetFor (HandlerSite m)
+--      , m ~ WidgetFor (HandlerSite m)
-     , RenderMessage (HandlerSite m) FormMessage
+--      , RenderMessage (HandlerSite m) FormMessage
-     )
+--      )
-  => r -> Journal -> Day -> m ()
+--   => r -> Journal -> Day -> m ()
+addModal :: Route App -> Journal -> Day -> Widget
 addModal addR j today = do
   (addView, addEnctype) <- generateFormPost (addForm j today)
   [whamlet|
@@ -48,12 +50,16 @@ addModal addR j today = do
           ^{addView}
 |]
 
+-- addForm ::
+--      (site ~ HandlerSite m, RenderMessage site FormMessage, MonadHandler m)
+--   => Journal
+--   -> Day
+--   -> Markup
+--   -> MForm m (FormResult Transaction, WidgetFor site ())
 addForm ::
-     (site ~ HandlerSite m, RenderMessage site FormMessage, MonadHandler m)
+  (MonadHandler m, RenderMessage (HandlerSite m) FormMessage) => 
-  => Journal
+  Journal -> Day -> Markup ->
-  -> Day
+  MForm m (FormResult Transaction, WidgetFor (HandlerSite m) ())
-  -> Markup
-  -> MForm m (FormResult Transaction, WidgetFor site ())
 addForm j today = identifyForm "add" $ \extra -> do
   (dateRes, dateView) <- mreq dateField dateFS Nothing
   (descRes, descView) <- mreq textField descFS Nothing