clear to eol on row end when using terminfo based terminal

src/Data/Terminfo/Eval.hs

@@ -162,7 +162,7 @@ serialize_cap_ops :: OutputBuffer -> CapOps -> EvalT IO OutputBuffer
 serialize_cap_ops out_ptr ops = foldM serialize_cap_op out_ptr ops
 
 serialize_cap_op :: OutputBuffer -> CapOp -> EvalT IO OutputBuffer
-serialize_cap_op !out_ptr ( Bytes !offset !byte_count !next_offset ) = do
+serialize_cap_op !out_ptr (Bytes !offset !byte_count !next_offset) = do
     !cap <- get >>= return . eval_expression
     let ( !start_ptr, _ ) = cap_bytes cap
         !src_ptr = start_ptr `plusPtr` offset

src/Data/Terminfo/Parse.hs

@@ -21,6 +21,8 @@ import Foreign.C.Types
 import Foreign.Marshal.Array
 import Foreign.Ptr
 
+import Numeric (showHex)
+
 import Text.ParserCombinators.Parsec
 
 type CapBytes = ( Ptr Word8, CSize )
@@ -31,7 +33,16 @@ data CapExpression = CapExpression
     , source_string :: !String
     , param_count :: !Word
     , param_ops :: !ParamOps
-    }
+    } deriving (Eq)
+
+instance Show CapExpression where
+    show c
+        = "CapExpression { " ++ show (cap_ops c) ++ " }"
+        ++ " <- [" ++ hex_dump ( map ( toEnum . fromEnum ) $! source_string c ) ++ "]"
+        ++ " <= " ++ show (source_string c)
+        where
+            hex_dump :: [Word8] -> String
+            hex_dump = foldr (\b s -> showHex b s) ""
 
 instance NFData CapExpression where
     rnf (CapExpression ops !_bytes !str !c !p_ops) 
@@ -55,7 +66,7 @@ data CapOp =
     | BitwiseOr | BitwiseXOr | BitwiseAnd
     | ArithPlus | ArithMinus
     | CompareEq | CompareLt | CompareGt
-    deriving ( Show )
+    deriving (Show, Eq)
 
 instance NFData CapOp where
     rnf (Bytes offset _count next_offset) = rnf offset `seq` rnf next_offset
@@ -76,7 +87,7 @@ instance NFData CapOp where
 type ParamOps = [ParamOp]
 data ParamOp =
       IncFirstTwo
-    deriving ( Show )
+    deriving (Show, Eq)
 
 instance NFData ParamOp where
     rnf IncFirstTwo = ()

src/Graphics/Vty/Terminal/Interface.hs

@@ -88,6 +88,8 @@ display_context t r = liftIO $ do
                            , serialize_set_attr = serialize_set_attr self
                            , default_attr_required_bytes = default_attr_required_bytes self
                            , serialize_default_attr = serialize_default_attr self
+                           , row_end_required_bytes = row_end_required_bytes self
+                           , serialize_row_end = serialize_row_end self
                            , inline_hack = return ()
                            }
     mfix (mk_display_context t . def_context)
@@ -120,6 +122,8 @@ data DisplayContext = DisplayContext
     -- | Reset the display attributes to the default display attributes
     , default_attr_required_bytes :: Int
     , serialize_default_attr :: OutputBuffer -> IO OutputBuffer
+    , row_end_required_bytes :: Int
+    , serialize_row_end :: OutputBuffer -> IO OutputBuffer
     -- | See Graphics.Vty.Terminal.XTermColor.inline_hack
     , inline_hack :: IO ()
     }
@@ -236,7 +240,7 @@ span_op_required_bytes dc fattr (AttributeChange attr) =
     in (c, fattr')
 span_op_required_bytes _dc fattr (TextSpan _ _ str) = (utf8_text_required_bytes str, fattr)
 span_op_required_bytes _dc _fattr (Skip _) = error "span_op_required_bytes for Skip."
-span_op_required_bytes _dc fattr (RowEnd _) = (0,fattr)
+span_op_required_bytes dc fattr (RowEnd _) = (row_end_required_bytes dc, fattr)
 
 serialize_output_ops :: DisplayContext
                         -> OutputBuffer 
@@ -272,6 +276,8 @@ serialize_span_ops dc y out_ptr in_fattr span_ops = do
                  (out_ptr', in_fattr)
                  span_ops
 
+-- | 
+-- TODO: move this into the terminal implementation?
 serialize_span_op :: DisplayContext
                      -> SpanOp 
                      -> OutputBuffer 
@@ -287,7 +293,9 @@ serialize_span_op _dc (TextSpan _ _ str) out_ptr fattr = do
     out_ptr' <- serialize_utf8_text str out_ptr
     return (out_ptr', fattr)
 serialize_span_op _dc (Skip _) _out_ptr _fattr = error "serialize_span_op for Skip"
-serialize_span_op _dc (RowEnd _) out_ptr fattr = return (out_ptr, fattr)
+serialize_span_op dc (RowEnd _) out_ptr fattr = do
+    out_ptr' <- serialize_row_end dc out_ptr
+    return (out_ptr', fattr)
 
 send_to_terminal :: Terminal -> Int -> (Ptr Word8 -> IO (Ptr Word8)) -> IO ()
 send_to_terminal t c f = allocaBytes (fromEnum c) $ \start_ptr -> do

src/Graphics/Vty/Terminal/Mock.hs

@@ -79,6 +79,11 @@ mock_terminal r = liftIO $ do
             , serialize_default_attr = \ptr -> do
                 poke ptr (toEnum $ fromEnum 'D')
                 return $ ptr `plusPtr` 1
+            -- row end is always visualized as the single character 'E'
+            , row_end_required_bytes = 1
+            , serialize_row_end = \ptr -> do
+                poke ptr (toEnum $ fromEnum 'E')
+                return $ ptr `plusPtr` 1
             }
         }
 

src/Graphics/Vty/Terminal/TerminfoBased.hs

@@ -47,6 +47,7 @@ data TerminfoCaps = TerminfoCaps
     , set_back_color :: CapExpression
     , set_default_attr :: CapExpression
     , clear_screen :: CapExpression
+    , clear_eol :: CapExpression
     , display_attr_caps :: DisplayAttrCaps
     }
 
@@ -109,6 +110,7 @@ reserve_terminal in_ID out_handle = liftIO $ mfix $ \self -> do
         <*> pure set_back_cap
         <*> require_cap ti "sgr0"
         <*> require_cap ti "clear"
+        <*> require_cap ti "el"
         <*> current_display_attr_caps ti
     let send_cap s = send_cap_to_terminal self (s terminfo_caps)
         maybe_send_cap s = when (isJust $ s terminfo_caps) . send_cap (fromJust . s)
@@ -212,7 +214,9 @@ mk_terminfo_display_context terminfo_caps self = do
         , attr_required_bytes = \_prev_attr _req_attr _diffs -> assumed_attr_required_bytes
         , serialize_set_attr = terminfo_serialize_set_attr self terminfo_caps
         , default_attr_required_bytes = cap_expression_required_bytes (set_default_attr terminfo_caps) []
-        , serialize_default_attr = \out_ptr -> serialize_cap_expression (set_default_attr terminfo_caps) [] out_ptr
+        , serialize_default_attr = serialize_cap_expression (set_default_attr terminfo_caps) []
+        , row_end_required_bytes = cap_expression_required_bytes (clear_eol terminfo_caps) []
+        , serialize_row_end = serialize_cap_expression (clear_eol terminfo_caps) []
         }
 
 -- | Instead of evaluating all the rules related to setting display attributes twice (once in

test/Verify/Data/Terminfo/Parse.hs

@@ -12,12 +12,6 @@ import Data.Word
 
 import Numeric
 
-instance Show CapExpression where
-    show c 
-        = "CapExpression { " ++ show (cap_ops c) ++ " }"
-        ++ " <- [" ++ hex_dump ( map ( toEnum . fromEnum ) $! source_string c ) ++ "]"
-        ++ " <= " ++ show (source_string c) 
-
 hex_dump :: [Word8] -> String
 hex_dump bytes = foldr (\b s -> showHex b s) "" bytes