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-rw-r--r--src/Text/Pandoc/Pretty.hs14
1 files changed, 11 insertions, 3 deletions
diff --git a/src/Text/Pandoc/Pretty.hs b/src/Text/Pandoc/Pretty.hs
index faf2a6797..5331587ce 100644
--- a/src/Text/Pandoc/Pretty.hs
+++ b/src/Text/Pandoc/Pretty.hs
@@ -60,6 +60,7 @@ module Text.Pandoc.Pretty (
, hsep
, vcat
, vsep
+ , nestle
, chomp
, inside
, braces
@@ -72,7 +73,7 @@ module Text.Pandoc.Pretty (
)
where
-import Data.Sequence (Seq, fromList, (<|), singleton, mapWithIndex)
+import Data.Sequence (Seq, fromList, (<|), singleton, mapWithIndex, viewl, ViewL(..))
import Data.Foldable (toList)
import Data.List (intercalate)
import Data.Monoid
@@ -80,8 +81,7 @@ import Data.String
import Control.Monad.State
import Data.Char (isSpace)
-data Monoid a =>
- RenderState a = RenderState{
+data RenderState a = RenderState{
output :: [a] -- ^ In reverse order
, prefix :: String
, usePrefix :: Bool
@@ -186,6 +186,14 @@ vcat = foldr ($$) empty
vsep :: [Doc] -> Doc
vsep = foldr ($+$) empty
+-- | Removes leading blank lines from a 'Doc'.
+nestle :: Doc -> Doc
+nestle (Doc d) = Doc $ go d
+ where go x = case viewl x of
+ (BlankLine :< rest) -> go rest
+ (NewLine :< rest) -> go rest
+ _ -> x
+
-- | Chomps trailing blank space off of a 'Doc'.
chomp :: Doc -> Doc
chomp d = Doc (fromList dl')