add Html and PlainText types, improved type safety

app/EpubParser.hs

@@ -48,6 +48,8 @@ import Types
     EpubEnv (..),
     InternalPath (..),
     TocEntry (..),
+    Html(..),
+    PlainText(..)
   )
 import Navigation (RawToc (..), guideToc, navDocHref, navToc, ncxToc)
 
@@ -181,11 +183,11 @@ renderRef ref = do
   env <- ask
   let InternalPath p = refPath ref
   pure $ case findEntry env p of
-    Nothing -> Chapter (refPath ref) (refTitle ref) "" (refIndex ref)
+    Nothing -> Chapter (refPath ref) (refTitle ref) (Html "") (refIndex ref)
     Just entry ->
       let withImages = embedImages env (takeDirectory p) (decodeEntry entry)
           body = fromMaybe "" (scrapeStringLike withImages bodyScraper)
-       in Chapter (refPath ref) (refTitle ref) body (refIndex ref)
+       in Chapter (refPath ref) (refTitle ref) (Html body) (refIndex ref)
 
 stripTags :: T.Text -> T.Text
 stripTags = T.unwords . T.words . go
@@ -197,14 +199,14 @@ stripTags = T.unwords . T.words . go
 
 -- | Read a chapter file and render its @\<body\>@ to plaintext, excluding
 -- any tags.
-readPText :: ChapterRef -> EpubAction T.Text
+readPText :: ChapterRef -> EpubAction PlainText
 readPText ref = do
   env <- ask
   let InternalPath p = refPath ref
   pure $ case findEntry env p of
-    Nothing -> ""
+    Nothing -> PlainText ""
     Just entry ->
-      stripTags $ fromMaybe "" (scrapeStringLike (decodeEntry entry) bodyScraper)
+      PlainText $ stripTags $ fromMaybe "" (scrapeStringLike (decodeEntry entry) bodyScraper)
 
 -- | Grab the contents of @\<body\>@, falling back to the whole document.
 bodyScraper :: Scraper T.Text T.Text

app/Types.hs

@@ -25,6 +25,8 @@ module Types
     EpubEnv (..),
     EpubAction,
     ReadMode(..),
+    Html(..),
+    PlainText(..),
   )
 where
 
@@ -56,11 +58,14 @@ data ChapterRef = ChapterRef
 data Chapter = Chapter
   { chapterPath :: InternalPath,
     chapterTitle :: T.Text,
-    chapterHtml :: T.Text,
+    chapterHtml :: Html,
     chapterIndex :: ChapterIndex
   }
   deriving (Show)
 
+newtype Html = Html T.Text deriving (Show, Eq)
+newtype PlainText = PlainText T.Text deriving (Show, Eq)
+
 -- | A node in the (possibly nested) table of contents. @tocTarget@ is the
 -- resolved chapter path; @tocFragment@ is the optional in-page anchor.
 data TocEntry = TocEntry
@@ -91,7 +96,7 @@ class BookInfo a where
   renderChapter :: a -> ChapterRef -> IO (Either String Chapter)
 
   -- | Extract a single chapter's plain text (tags stripped), for search.
-  chapterText :: a -> ChapterRef -> IO (Either String T.Text)
+  chapterText :: a -> ChapterRef -> IO (Either String PlainText)
 
 -- | Mutable application state, held in a 'Control.Concurrent.STM.TVar'.
 -- Rendered chapters accumulate in 'stCache' as the reader visits them.
@@ -106,7 +111,7 @@ data AppState = AppState
     stGen :: Int,
     stUse :: M.Map ChapterIndex Int,
     stTick :: Int,
-    stSearchIndex :: M.Map ChapterIndex T.Text,
+    stSearchIndex :: M.Map ChapterIndex PlainText,
     stMode :: ReadMode
   }
 

app/UI.hs

@@ -39,6 +39,8 @@ import Types
     TocEntry (..),
     UserAction (..),
     ReadMode(..),
+    Html(..),
+    PlainText(..),
   )
 
 -- | Widget handles the rest of the module needs.
@@ -402,7 +404,7 @@ showLoading :: Ctx -> ChapterRef -> IO ()
 showLoading ctx ref = do
   mode <- getMode ctx
   setWindowTitle ctx (refIndex ref) (refTitle ref)
-  WebKit.webViewLoadHtml (appWebView (ctxWidgets ctx)) (wrapHtml "<p style=\"opacity:0.5\">Loading…</p>" StartTop mode) Nothing
+  WebKit.webViewLoadHtml (appWebView (ctxWidgets ctx)) (wrapHtml (Html "<p style=\"opacity:0.5\">Loading…</p>") StartTop mode) Nothing
 
 setWindowTitle :: Ctx -> ChapterIndex -> T.Text -> IO ()
 setWindowTitle ctx (ChapterIndex i) chapter = do
@@ -419,8 +421,8 @@ setZoom ctx level = do
 -- | Wrap a chapter's @\<body\>@ fragment in a full, styled HTML document
 -- (WebKit renders bare fragments unreliably). If @frag@ names an anchor, a
 -- small script scrolls it into view after load.
-wrapHtml :: T.Text -> StartAt -> ReadMode -> T.Text
-wrapHtml body start mode =
+wrapHtml :: Html -> StartAt -> ReadMode -> T.Text
+wrapHtml (Html body) start mode =
   T.concat
     [ "<!DOCTYPE html><html><head><meta charset=\"utf-8\"><style>",
       ( case mode of
@@ -492,11 +494,11 @@ evalJSBool wv src k =
       b <- JSC.valueToBoolean val
       k b)
 
-chaptersMatching :: T.Text -> M.Map ChapterIndex T.Text -> [ChapterIndex]
+chaptersMatching :: T.Text -> M.Map ChapterIndex PlainText -> [ChapterIndex]
 chaptersMatching q = map fst . filter (matches q . snd) . M.toAscList
 
-matches :: T.Text -> T.Text -> Bool
-matches q txt = T.toCaseFold q `T.isInfixOf` T.toCaseFold txt
+matches :: T.Text -> PlainText -> Bool
+matches q (PlainText txt) = T.toCaseFold q `T.isInfixOf` T.toCaseFold txt
 
 nextMatch :: ChapterIndex -> [ChapterIndex] -> Maybe ChapterIndex
 nextMatch cur hits =