From 30e51ed41bdc90765abcad594135709b3c204515 Mon Sep 17 00:00:00 2001
From: Jaro <jaro@argonaut-constellation.org>
Date: Fri, 17 Mar 2023 14:34:18 +0100
Subject: [PATCH] Refactor pretty printing for golden tests.

---
 test/Data/Text/ParagraphLayoutSpec.hs | 75 ++++++++++++++++++++-------
 1 file changed, 55 insertions(+), 20 deletions(-)

diff --git a/test/Data/Text/ParagraphLayoutSpec.hs b/test/Data/Text/ParagraphLayoutSpec.hs
index b3f1d81..03d409d 100644
--- a/test/Data/Text/ParagraphLayoutSpec.hs
+++ b/test/Data/Text/ParagraphLayoutSpec.hs
@@ -1,6 +1,5 @@
 module Data.Text.ParagraphLayoutSpec (spec) where
 
-import Data.List (intersperse)
 import Data.Text.Glyphize (Font)
 
 import Test.Hspec
@@ -11,48 +10,84 @@ import Data.Text.ParagraphLayout.FontLoader
 import Data.Text.ParagraphLayout.ParagraphData
 import Data.Text.ParagraphLayout.Rect
 
+class PrettyShow a where
+    prettyShow :: a -> String
 
-prettyShow :: ParagraphLayout -> String
-prettyShow (ParagraphLayout pr sls) = showParagraphLayout where
-    showParagraphLayout = concat
+instance PrettyShow ParagraphLayout where
+    prettyShow (ParagraphLayout pr sls) = concat
         [ "ParagraphLayout {paragraphRect = "
         , show pr
-        , ", spanLayouts = ["
+        , commaSpace
+        , "spanLayouts = ["
         , newline
-        , showSpanLayouts
+        , indent1
+        , concat $ indentedList indent1 $ map prettyShow sls
         , newline
         , "]}"
         , newline
         ]
-    showSpanLayouts = concat $ intersperse commaNewline $ map showSpanLayout sls
-    showSpanLayout (SpanLayout frags) = concat
-        [ indent1
-        , "SpanLayout ["
-        , concat $ intersperse ", " $ map showFrag frags
+
+instance PrettyShow SpanLayout where
+    prettyShow (SpanLayout frags) = concat
+        [ "SpanLayout ["
+        , concat $ inlineList $ map prettyShow frags
         , "]"
         ]
-    showFrag (Fragment r pen glyphs) = concat
+
+instance PrettyShow Fragment where
+    prettyShow (Fragment r pen glyphs) = concat
         [ "Fragment {fragmentRect = "
         , show r
-        , ", "
+        , commaSpace
         , "fragmentPen = "
         , show pen
-        , ", "
+        , commaSpace
         , "fragmentGlyphs ="
         , newline
         , indent2
         , "["
-        , showGlyphs glyphs
+        , concat $ indentedList indent2 $ map show glyphs
         , "]"
         , newline
         , indent1
         , "}"
         ]
-    showGlyphs = concat . intersperse (commaNewline ++ indent2) . map show
-    indent1 = "    "
-    indent2 = indent1 ++ indent1
-    newline = "\n"
-    commaNewline = "," ++ newline
+
+inlineList :: [String] -> [String]
+inlineList items = suffixInit commaSpace items
+
+indentedList :: String -> [String] -> [String]
+indentedList indent items = prefixTail indent $ suffixInit commaNewline items
+
+suffixInit :: String -> [String] -> [String]
+suffixInit suffix = mapInit (++suffix)
+
+mapInit :: (a -> a) -> [a] -> [a]
+mapInit _ [] = []
+mapInit _ [x] = [x]
+mapInit f (x:y:ys) = f x : mapInit f (y:ys)
+
+prefixTail :: String -> [String] -> [String]
+prefixTail prefix = mapTail (prefix++)
+
+mapTail :: (a -> a) -> [a] -> [a]
+mapTail _ [] = []
+mapTail f (x:xs) = x:(map f xs)
+
+indent1 :: String
+indent1 = "    "
+
+indent2 :: String
+indent2 = indent1 ++ indent1
+
+newline :: String
+newline = "\n"
+
+commaSpace :: String
+commaSpace = ", "
+
+commaNewline :: String
+commaNewline = "," ++ newline
 
 shouldBeGolden :: ParagraphLayout -> FilePath -> Golden ParagraphLayout
 shouldBeGolden output_ name = Golden
-- 
2.30.2