From cfd9357931f136f52df2becd0af605111e102234 Mon Sep 17 00:00:00 2001
From: Michael Andreen <harv@ruin.nu>
Date: Sat, 11 Dec 2004 15:51:08 +0000
Subject: [PATCH] Possible to list and get old revisions

---
 Main.hs | 55 ++++++++++++++++++++++++++++++++++++++++---------------
 Wiki.hs |  8 ++++++--
 2 files changed, 46 insertions(+), 17 deletions(-)

diff --git a/Main.hs b/Main.hs
index b261901..ea9316b 100644
--- a/Main.hs
+++ b/Main.hs
@@ -15,7 +15,7 @@ testDB = createPGB "wave" "wiki" "wiki" "12wiki34db"
 
 main = do 
 	db <- testDB
-	runWithHook [] (\(key:act) -> sp db key) $ sp db "MainPage"
+	runWithHook [] (\(key:act) -> showPage db key) $ showPage db "MainPage"
 
 ps a = standardQuery "Hello" a
 
@@ -36,39 +36,64 @@ editPage db key = do
 		p $ defaultSubmit (F3 t a c) (savePage db key) (attr "value" "Send")
 		--submit0 (sp db key []) (attr "value" "Send1")
 
-sp db key = do
-	s <- io $ getCurrent db key 
-	standardQuery key $ showPage db key s
 
 savePage db key (F3 t a c) = do
 	io $ update db key fulltext author comment
-	s <- io $ getCurrent db key 
-	standardQuery key $ do
-		showPage db key s
+	showPage db key 
   where
   	fulltext = value t
 	author = value a
 	comment = value c 
 
-showPage db key s = do
+showPage db key = do
+	s <- io $ getCurrent db key 
+	standardQuery key $ do
 		case s of
 			Nothing -> text "No text added for this keyword"
 			Just (full, date) -> do
-				case parse wikiParser "" full of
-					Right n -> ex n	
-					Left e -> do
-						text "PARSE ERROR: "
-						text (show e)
-						p $ text full
+				parseText full	
 				p $ text $ "Last edited: "++date
 		footer db key
 
+parseText full = case parse wikiParser "" full of
+	Right n -> ex n	
+	Left e -> do
+		text "PARSE ERROR: "
+		text (show e)
+		p $ text full
+
 footer db key = do
 	hr empty
 	table $ tr $ do
 		td $ submitLink0 (editPage db key) (text "Edit this page")
-		td $ text "Keyword: " >> activate (sp db) textInputField empty
+		td $ submitLink0 (listRevs db key) (text "List old versions")
+		td $ text "Keyword: " 
+		td $ activate (showPage db) textInputField empty
+
+listRevs db key = do 
+	list <- io $ getList db key 
+	standardQuery key $ table $ do
+		tr $ mapM (\header -> th (text header))
+			["Id", "Date", "Author", "Comment"]
+		mapM (revRow db key) list
+
+linkKey db key = submitLink0 (showPage db key) (text key)
+
+revRow db key (id, date, author, comment) = tr $ do
+	td $ submitLink0 (showRev db key id) (text id) 
+	td $ text date
+	td $ linkKey db author
+	td $ text comment
+
+showRev db key id = do
+	s <- io $ get db key id
+	standardQuery key $ do
+		case s of 
+			Nothing -> text "No such revision"
+			Just s -> parseText s
+		footer db key
 
+	
 ex [] = return ()
 ex ((Paragraph):xs) = do
 	p empty
diff --git a/Wiki.hs b/Wiki.hs
index 337d715..7d337c9 100644
--- a/Wiki.hs
+++ b/Wiki.hs
@@ -20,7 +20,7 @@ class Backend a where
 	getList :: a -> String -> IO [(String, String, String, String)]
 
 	--Keyword -> id -> Full text
-	get :: a -> String -> String -> IO String
+	get :: a -> String -> String -> IO (Maybe String)
 
 	--Keyword -> id -> ()
 	setCurrent :: a -> String -> String -> IO Bool
@@ -100,7 +100,11 @@ instance Backend PGB where
 		list <- selectReturnTuples db $ "SELECT id, timestamp, author, comment from fulltexts WHERE keyword = "++tov key
 		return $ map (\[id,date,author,comment] -> (id,date,author,comment)) list
 
-	get (PGB db) key id = return ""
+	get (PGB db) key id = do
+		list <- selectReturnTuples db $ "SELECT fulltext from fulltexts WHERE id = "++tov id	
+		case list of
+			[s]:_ -> return (Just s)
+			_ -> return Nothing
 
 	setCurrent (PGB db) key id = do
 		full <- selectReturnTuples db $ "SELECT keyword FROM fulltexts WHERE keyword="++tov key++" AND id='"++id++"'"
-- 
2.39.2