From f9dc35994f3a50083efe5eaf9e6405e98d49fd40 Mon Sep 17 00:00:00 2001
From: Joey Hess <joeyh@joeyh.name>
Date: Tue, 18 Apr 2017 12:11:32 -0400
Subject: smart quoting

---
 Graphviz.hs | 29 +++++++++++++++++++++++------
 1 file changed, 23 insertions(+), 6 deletions(-)

(limited to 'Graphviz.hs')

diff --git a/Graphviz.hs b/Graphviz.hs
index 6a5cb52..9d508c8 100644
--- a/Graphviz.hs
+++ b/Graphviz.hs
@@ -52,7 +52,7 @@ genGraph opts ls = digraph (Str "debug-me") $ do
   where
 	showactivity s (ActivitySeen { activitySeen = (a, h) }) = do
 		node (display h) $ s ++
-			[ textLabel $ display $ activity a
+			[ textLabel $ prettyDisplay $ activity a
 			, shape BoxShape
 			]
 		case activity a of
@@ -69,7 +69,7 @@ genGraph opts ls = digraph (Str "debug-me") $ do
 		linkprev s a h
 	showactivity s (ActivityEntered { activityEntered = (a, h) }) = do
 			node (display h) $ s ++
-				[ textLabel $ display $ activity a
+				[ textLabel $ prettyDisplay $ activity a
 				, shape Circle
 				]
 			linkprev s a h
@@ -78,23 +78,40 @@ genGraph opts ls = digraph (Str "debug-me") $ do
 		Just p -> link p h s
 	link a b s = edge (display a) (display b) $ s ++
 		if graphvizShowHashes opts
-			then [ textLabel (shorthash a) ]
+			then [ textLabel (prettyDisplay a) ]
 			else []
-	-- The "h:" prefix is to work around this bug:
-	-- https://github.com/ivan-m/graphviz/issues/16
-	shorthash h = display $ Val $ "h:" <> (B.take 5 $ val $ hashValue h)
 
 xcolor :: X11Color -> Attribute
 xcolor c = Color [toWC $ X11Color c]
 
 class Display t where
+	-- Display more or less as-is, for graphviz.
 	display :: t -> T.Text
+	-- Prettified display for user-visible labels etc.
+	prettyDisplay :: t -> T.Text
+	prettyDisplay = prettyDisplay . display
+
+instance Display T.Text where
+	display = id
+	prettyDisplay t
+		| all visible s = t
+		| all isPrint s && not (leadingws s) && not (leadingws (reverse s)) = t
+		| otherwise = T.pack (show s)
+	  where
+		s = T.unpack t
+		visible c = isPrint c && not (isSpace c)
+		leadingws (c:_) = isSpace c
+		leadingws _ = False
 
 instance Display Val where
 	display (Val b) = T.decodeUtf8With lenientDecode (L.fromStrict b)
 
 instance Display Hash where
 	display (Hash m h) = T.pack (show m) <> display h
+	-- Use short hash for pretty display.
+	-- The "h:" prefix is to work around this bug:
+	-- https://github.com/ivan-m/graphviz/issues/16
+	prettyDisplay h = display $ Val $ "h:" <> (B.take 5 $ val $ hashValue h)
 
 instance Display Seen where
 	display = display . seenData
-- 
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