Display table as proper markdown.

Markdown doesn't do multiline headings unless you have an explicit break in the header.

Author: mchav

src/Data/DataFrame/Display/Terminal/PrettyPrint.hs

@@ -50,4 +50,14 @@ showTable header types rows =
       border = T.intercalate "---" [T.replicate width (T.singleton '-') | width <- widths]
       separator = T.intercalate "-|-" [T.replicate width (T.singleton '-') | width <- widths]
       fillCols fill cols = T.intercalate " | " [fill c width col | (c, width, col) <- zip3 cs widths cols]
-   in T.unlines $ border : fillCols colTitleFill header : separator : fillCols colTitleFill types : separator : map (fillCols colValueFill) rows
+   in T.unlines $ border : fillCols colTitleFill header : separator : fillCols colTitleFill types : separator : map (fillCols colValueFill) rows
+
+showTableProperMarkdown :: [T.Text] -> [T.Text] -> [[T.Text]] -> T.Text
+showTableProperMarkdown header types rows =
+  let headerWithTypes = zipWith (\h t -> h <> "<br>" <> t) header types
+      cs = map (\h -> ColDesc center h left) headerWithTypes
+      widths = [maximum $ map T.length col | col <- transpose $ headerWithTypes : rows]
+      border = T.intercalate "---" [T.replicate width (T.singleton '-') | width <- widths]
+      separator = T.intercalate "-|-" [T.replicate width (T.singleton '-') | width <- widths]
+      fillCols fill cols = T.intercalate " | " [fill c width col | (c, width, col) <- zip3 cs widths cols]
+   in T.unlines $ border : fillCols colTitleFill headerWithTypes : separator : map (fillCols colValueFill) rows

src/Data/DataFrame/Internal/DataFrame.hs

@@ -39,10 +39,10 @@ instance Eq DataFrame where
 
 instance Show DataFrame where
   show :: DataFrame -> String
-  show d = T.unpack (asText d)
+  show d = T.unpack (asText d False)
 
-asText :: DataFrame -> T.Text
-asText d =
+asText :: DataFrame -> Bool -> T.Text
+asText d properMarkdown =
   let header = "index" : map fst (sortBy (compare `on` snd) $ M.toList (columnIndices d))
       types = V.toList $ V.filter (/= "") $ V.map getType (columns d)
       getType Nothing = ""
@@ -68,7 +68,7 @@ asText d =
       rows =
         transpose $
           zipWith (curry (V.toList . getTextColumnFromFrame d)) [0..] header
-   in showTable header ("Int":types) rows
+   in (if properMarkdown then showTableProperMarkdown else showTable) header ("Int":types) rows
 
 -- | O(1) Creates an empty dataframe
 empty :: DataFrame