Lua Utils module: add function blocks_to_inlines (#4799)

Exposes a function converting which flattenes a list of blocks into a
list of inlines. An example use case would be the conversion of Note
elements into other inlines.

2 files changed, 21 insertions, 2 deletions

diff --git a/src/Text/Pandoc/Lua/Module/Utils.hs b/src/Text/Pandoc/Lua/Module/Utils.hs
index 7fa4616be..7016c7ebd 100644
--- a/src/Text/Pandoc/Lua/Module/Utils.hs
+++ b/src/Text/Pandoc/Lua/Module/Utils.hs
@@ -42,6 +42,7 @@ import Text.Pandoc.Lua.Util (addFunction, popValue)
 import qualified Data.Digest.Pure.SHA as SHA
 import qualified Data.ByteString.Lazy as BSL
 import qualified Foreign.Lua as Lua
+import qualified Text.Pandoc.Builder as B
 import qualified Text.Pandoc.Filter.JSON as JSONFilter
 import qualified Text.Pandoc.Shared as Shared
 
@@ -49,6 +50,7 @@ import qualified Text.Pandoc.Shared as Shared
 pushModule :: Maybe FilePath -> Lua NumResults
 pushModule mbDatadir = do
   Lua.newtable
+  addFunction "blocks_to_inlines" blocksToInlines
   addFunction "hierarchicalize" hierarchicalize
   addFunction "normalize_date" normalizeDate
   addFunction "run_json_filter" (runJSONFilter mbDatadir)
@@ -57,6 +59,14 @@ pushModule mbDatadir = do
   addFunction "to_roman_numeral" toRomanNumeral
   return 1
 
+-- | Squashes a list of blocks into inlines.
+blocksToInlines :: [Block] -> Lua.Optional [Inline] -> Lua [Inline]
+blocksToInlines blks optSep = do
+  let sep = case Lua.fromOptional optSep of
+              Just x -> B.fromList x
+              Nothing -> Shared.defaultBlocksSeparator
+  return $ B.toList (Shared.blocksToInlinesWithSep sep blks)
+
 -- | Convert list of Pandoc blocks into (hierarchical) list of Elements.
 hierarchicalize :: [Block] -> Lua [Shared.Element]
 hierarchicalize = return . Shared.hierarchicalize
diff --git a/src/Text/Pandoc/Shared.hs b/src/Text/Pandoc/Shared.hs
index 5b011c46a..412de99a0 100644
--- a/src/Text/Pandoc/Shared.hs
+++ b/src/Text/Pandoc/Shared.hs
@@ -94,6 +94,8 @@ module Text.Pandoc.Shared (
                      -- * for squashing blocks
                      blocksToInlines,
                      blocksToInlines',
+                     blocksToInlinesWithSep,
+                     defaultBlocksSeparator,
                      -- * Safe read
                      safeRead,
                      -- * Temp directory
@@ -757,12 +759,19 @@ blocksToInlinesWithSep sep =
   mconcat . intersperse sep . map blockToInlines
 
 blocksToInlines' :: [Block] -> Inlines
-blocksToInlines' = blocksToInlinesWithSep parSep
-  where parSep = B.space <> B.str "¶" <> B.space
+blocksToInlines' = blocksToInlinesWithSep defaultBlocksSeparator
 
 blocksToInlines :: [Block] -> [Inline]
 blocksToInlines = B.toList . blocksToInlines'
 
+-- | Inline elements used to separate blocks when squashing blocks into
+-- inlines.
+defaultBlocksSeparator :: Inlines
+defaultBlocksSeparator =
+  -- This is used in the pandoc.utils.blocks_to_inlines function. Docs
+  -- there should be updated if this is changed.
+  B.space <> B.str "¶" <> B.space
+
 
 --
 -- Safe read