hxbrief: Implement --yield to keep pattern while dropping

This is similar to piping your output to grep, only
our patterns are much weaker (as of yet), you can see
the intermediate output, and you can also still tee the
whole (unfiltered) output to a file at the same time.

src-hxbrief/Main.hs

@@ -86,11 +86,13 @@ data StreamKind = StdOut | StdErr
   deriving (Eq, Show)
 
 data JoinMode
-  = JoinAll
+  = JoinYield
+  | JoinAll
   | JoinSpecific
 
 data JoinedInfo
   = JoinedNot
+  | JoinedYield
   | JoinedAll Int
   | Joined Int String [String] -- pattern, prefix
 
@@ -182,6 +184,13 @@ dispatchLine line@(kind, str) = do
       when (c_keepStderr conf /= Drop) $ errorConcurrent (fReset ++ str ++ "\n")
   modify $ \s -> s { s_history = line : s_history s }
 
+dispatchYielded :: (StreamKind, String) -> StateT State IO ()
+dispatchYielded line@(kind, str) = do
+  liftIO $ case kind of
+    StdOut -> outputConcurrent (fReset ++ str ++ "\n")
+    StdErr -> errorConcurrent (fReset ++ str ++ "\n")
+  modify $ \s -> s { s_history = line : s_history s }
+
 showPattern :: String -> String
 showPattern p = p >>= \case
   '*' -> setFGColorVivid Ansi.Yellow ++ "…" ++ fReset
@@ -256,6 +265,7 @@ summarizeLines cur@(kind, line) = do
                       ( cur
                       , case match of
                         Nothing                  -> JoinedNot
+                        Just (JoinYield   , _  ) -> JoinedYield
                         Just (JoinAll     , _  ) -> JoinedAll 1
                         Just (JoinSpecific, pat) -> Joined 1 pat (words line)
                       )
@@ -267,10 +277,26 @@ summarizeLines cur@(kind, line) = do
                         ( cur
                         , case match of
                           Nothing                  -> JoinedNot
+                          Just (JoinYield   , _  ) -> JoinedYield
                           Just (JoinAll     , _  ) -> JoinedAll 1
                           Just (JoinSpecific, pat) -> Joined 1 pat (words line)
                         )
         }
+    (Just (oldLine, JoinedYield), Nothing) -> do
+      dispatchYielded oldLine
+      put s { s_summary = Just (cur, JoinedNot) }
+    (Just (oldLine, JoinedYield), _) -> do
+      dispatchYielded oldLine
+      put s
+        { s_summary = Just
+                        ( cur
+                        , case match of
+                          Nothing                  -> JoinedNot
+                          Just (JoinAll     , _  ) -> JoinedAll 1
+                          Just (JoinSpecific, pat) -> Joined 1 pat (words line)
+                          Just (JoinYield   , _  ) -> JoinedYield
+                        )
+        }
     (Just ((oldKind, _), JoinedAll i), Nothing) -> do
       dispatchSkipped oldKind i
       put s { s_summary = Just (cur, JoinedNot) }
@@ -278,6 +304,9 @@ summarizeLines cur@(kind, line) = do
       dispatchPat oldKind i oldPat oldPrefix
       put s { s_summary = Just (cur, JoinedNot) }
     (Just ((oldKind, _), JoinedAll i), Just joiner) -> case joiner of
+      (JoinYield, _pat) -> do
+        dispatchSkipped oldKind i
+        put s { s_summary = Just (cur, JoinedYield) }
       (JoinAll, _)
         | kind == oldKind -> do
           put s { s_summary = Just (cur, JoinedAll (i + 1)) }
@@ -302,6 +331,7 @@ summarizeLines cur@(kind, line) = do
             { s_summary = Just
                             ( cur
                             , case joiner of
+                              (JoinYield   , _  ) -> JoinedYield
                               (JoinAll     , _  ) -> JoinedAll 1
                               (JoinSpecific, pat) -> Joined 1 pat (words line)
                             )
@@ -354,8 +384,12 @@ processLine newPair@(kind, _) = execStateT $ do
           ++ " lines)"
           )
           : prettyLines
+      Just ((StdOut, line), JoinedYield) ->
+        (fWhiteDis ++ "│ " ++ fReset ++ ellipse line) : prettyLines
       Just ((StdErr, line), JoinedNot) ->
         (fRedDis ++ "│ " ++ fReset ++ ellipse line) : prettyLines
+      Just ((StdErr, line), JoinedYield) ->
+        (fRedDis ++ "│ " ++ fReset ++ ellipse line) : prettyLines
       Just ((StdErr, line), JoinedAll 1) ->
         (fRedDis ++ "│ " ++ fReset ++ ellipse line) : prettyLines
       Just ((StdErr, _line), JoinedAll i) ->
@@ -424,6 +458,7 @@ main = B.mainFromCmdParser $ do
   summarize       <- B.addFlagStringParams "s" ["summarize"] "PATTERN" mempty
   skip            <- B.addFlagStringParams "x" ["skip"] "PATTERN" mempty
   label           <- B.addFlagStringParams "" ["label"] "STRING" mempty
+  yield           <- B.addFlagStringParams "y" ["yield"] "PATTERN" mempty
   omitSummary     <- B.addSimpleBoolFlag "" ["omit-summary"] mempty
   tee             <- B.addFlagStringParams
     ""
@@ -525,7 +560,8 @@ main = B.mainFromCmdParser $ do
                                   | conflateStderr || conflateBoth -> Conflate
                                   | dropStderr || dropBoth -> Drop
                                   | otherwise -> Keep
-              , c_summarize   = (summarize <&> \x -> (JoinSpecific, x))
+              , c_summarize   = (yield <&> \x -> (JoinYield, x))
+                                ++ (summarize <&> \x -> (JoinSpecific, x))
                                 ++ (skip <&> \x -> (JoinAll, x))
               , c_outFile     = Nothing
               , c_errFile     = Nothing
@@ -602,6 +638,7 @@ main = B.mainFromCmdParser $ do
               gets s_summary >>= \case
                 Nothing                       -> pure ()
                 Just (line     , JoinedNot  ) -> dispatchLine line
+                Just (line     , JoinedYield) -> dispatchYielded line
                 Just ((kind, _), JoinedAll i) -> dispatchSkipped kind i
                 Just ((kind, _), Joined i pat prefix) ->
                   dispatchPat kind i pat prefix