From dc1a532225cba53b5d63df1bca77d5498ac34810 Mon Sep 17 00:00:00 2001
From: DavidM <david.dmcbride@moxune.com>
Date: Mon, 20 Jun 2011 20:42:34 -0400
Subject: [PATCH] Added multiple select fields to yesod and to demo.

---
 Yesod/Form/Fields.hs    | 31 +++++++++++++++++++++++++++++++
 Yesod/Form/Functions.hs |  1 +
 hello-forms.hs          |  4 +++-
 3 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/Yesod/Form/Fields.hs b/Yesod/Form/Fields.hs
index 9fedf1b2..b9ed0e39 100644
--- a/Yesod/Form/Fields.hs
+++ b/Yesod/Form/Fields.hs
@@ -17,6 +17,7 @@ module Yesod.Form.Fields
     , emailField
     , searchField
     , selectField
+    , multiSelectField
     , AutoFocus
     , urlField
     , doubleField
@@ -40,6 +41,9 @@ import Network.URI (parseURI)
 import Database.Persist (PersistField)
 import Text.HTML.SanitizeXSS (sanitizeBalance)
 import Control.Monad (when, unless)
+import Data.List (intersect, nub)
+import Data.Either (rights)
+import Data.Maybe (catMaybes)
 
 import qualified Blaze.ByteString.Builder.Html.Utf8 as B
 import Blaze.ByteString.Builder (writeByteString, toLazyByteString)
@@ -315,6 +319,11 @@ selectField = selectFieldHelper
     (\_theId _name isSel -> [WHAMLET|<option value=none :isSel:selected>_{MsgSelectNone}|])
     (\_theId _name value isSel text -> addHtml [HTML|<option value=#{value} :isSel:selected>#{text}|])
 
+multiSelectField :: (Show a, Eq a, Monad monad, RenderMessage master FormMessage) => [(Text, a)] -> Field (GGWidget master (GGHandler sub master monad) ()) FormMessage [a]
+multiSelectField = multiSelectFieldHelper
+    (\theId name inside -> [WHAMLET|<select ##{theId} multiple name=#{name}>^{inside}|])
+    (\_theId _name value isSel text -> addHtml [HTML|<option value=#{value} :isSel:selected>#{text}|])
+
 radioField :: (Eq a, Monad monad, RenderMessage master FormMessage) => [(Text, a)] -> Field (GGWidget master (GGHandler sub master monad) ()) FormMessage a
 radioField = selectFieldHelper
     (\theId _name inside -> [WHAMLET|<div ##{theId}>^{inside}|])
@@ -354,6 +363,28 @@ boolField = Field
       "no" -> Right $ Just False
       t -> Left $ MsgInvalidBool t
 
+multiSelectFieldHelper :: (Show a, Eq a, Monad monad)
+        => (Text -> Text -> GGWidget master monad () -> GGWidget master monad ())
+        -> (Text -> Text -> Text -> Bool -> Text -> GGWidget master monad ())
+        -> [(Text, a)] -> Field (GGWidget master monad ()) FormMessage [a]
+multiSelectFieldHelper outside inside opts = Field
+    { fieldParse = selectParser
+    , fieldView = \theId name vals _ ->
+        outside theId name $ do
+            flip mapM_ pairs $ \pair -> inside
+                theId
+                name
+                (pack $ show $ fst pair)
+                ((fst pair) `elem` (maybe [] selectedVals vals))
+                (fst $ snd pair)
+    }
+  where
+    pairs = zip [1 :: Int ..] opts -- FIXME use IntMap
+    rpairs = zip (map snd opts) [1 :: Int ..]
+    selectedVals vals = map snd $ filter (\y -> fst y `elem` vals) rpairs
+    selectParser [] = Right Nothing
+    selectParser xs | not $ null (["", "none"] `intersect` xs) = Right Nothing
+                    | otherwise = (Right . Just . map snd . catMaybes . map (\y -> lookup y pairs) . nub . map fst . rights . map Data.Text.Read.decimal) xs
 
 selectFieldHelper :: (Eq a, Monad monad)
         => (Text -> Text -> GGWidget master monad () -> GGWidget master monad ())
diff --git a/Yesod/Form/Functions.hs b/Yesod/Form/Functions.hs
index 49277705..cb42bdb6 100644
--- a/Yesod/Form/Functions.hs
+++ b/Yesod/Form/Functions.hs
@@ -103,6 +103,7 @@ mhelper :: (Monad m, RenderMessage master msg, RenderMessage master msg2)
         -> (a -> FormResult b) -- ^ on success
         -> Bool -- ^ is it required?
         -> Form master (GGHandler sub master m) (FormResult b, FieldView xml)
+
 mhelper Field {..} FieldSettings {..} mdef onMissing onFound isReq = do
     mp <- askParams
     name <- maybe newFormIdent return fsName
diff --git a/hello-forms.hs b/hello-forms.hs
index ccab8f77..cd10b635 100644
--- a/hello-forms.hs
+++ b/hello-forms.hs
@@ -12,12 +12,14 @@ data Fruit = Apple | Banana | Pear
 fruits :: [(Text, Fruit)]
 fruits = map (\x -> (pack $ show x, x)) [minBound..maxBound]
 
-myForm = fixType $ runFormGet $ renderDivs $ pure (,,,,,,)
+myForm = fixType $ runFormGet $ renderDivs $ pure (,,,,,,,,)
     <*> areq boolField "Bool field" Nothing
     <*> aopt boolField "Opt bool field" Nothing
     <*> areq textField "Text field" Nothing
     <*> areq (selectField fruits) "Select field" Nothing
     <*> aopt (selectField fruits) "Opt select field" Nothing
+    <*> areq (multiSelectField fruits) "Multi select field" Nothing
+    <*> aopt (multiSelectField fruits) "Opt multi select field" Nothing
     <*> aopt intField "Opt int field" Nothing
     <*> aopt (radioField fruits) "Opt radio" Nothing