Lua: marshal Pandoc values as userdata

2 files changed, 36 insertions, 11 deletions

diff --git a/src/Text/Pandoc/Lua/Marshaling/AST.hs b/src/Text/Pandoc/Lua/Marshaling/AST.hs
index eedf00a94..6f97bdd36 100644
--- a/src/Text/Pandoc/Lua/Marshaling/AST.hs
+++ b/src/Text/Pandoc/Lua/Marshaling/AST.hs
@@ -40,7 +40,7 @@ import Control.Monad ((<$!>), (>=>))
 import HsLua hiding (Operation (Div))
 import Text.Pandoc.Definition
 import Text.Pandoc.Lua.Util (pushViaConstr', pushViaConstructor)
-import Text.Pandoc.Lua.Marshaling.CommonState ()
+import Text.Pandoc.Lua.Marshaling.List (pushPandocList)
 
 import qualified HsLua as Lua
 import qualified Text.Pandoc.Lua.Util as LuaUtil
@@ -49,19 +49,32 @@ instance Pushable Pandoc where
   push = pushPandoc
 
 pushPandoc :: LuaError e => Pusher e Pandoc
-pushPandoc (Pandoc meta blocks) =
-  pushViaConstr' "Pandoc" [pushList pushBlock blocks, push meta]
+pushPandoc = pushUD typePandoc
 
 peekPandoc :: LuaError e => Peeker e Pandoc
-peekPandoc = fmap (retrieving "Pandoc value")
-  . typeChecked "table" Lua.istable $ \idx -> do
-      meta <- peekFieldRaw peekMeta "meta" idx
-      blks <- peekFieldRaw peekBlocks "blocks" idx
-      return $ Pandoc meta blks
+peekPandoc = retrieving "Pandoc value" . peekUD typePandoc
+
+typePandoc :: LuaError e => DocumentedType e Pandoc
+typePandoc = deftype "Pandoc"
+  [ operation Eq $ defun "__eq"
+     ### liftPure2 (==)
+     <#> parameter (optional . peekPandoc) "doc1" "pandoc" ""
+     <#> parameter (optional . peekPandoc) "doc2" "pandoc" ""
+     =#> functionResult pushBool "boolean" "true iff the two values are equal"
+  ]
+  [ property "blocks" "list of blocks"
+      (pushPandocList pushBlock, \(Pandoc _ blks) -> blks)
+      (peekList peekBlock, \(Pandoc m _) blks -> Pandoc m blks)
+  , property "meta" "document metadata"
+      (pushMeta, \(Pandoc meta _) -> meta)
+      (peekMeta, \(Pandoc _ blks) meta -> Pandoc meta blks)
+  ]
 
 instance Pushable Meta where
-  push (Meta mmap) =
-    pushViaConstr' "Meta" [push mmap]
+  push = pushMeta
+
+pushMeta :: LuaError e => Pusher e Meta
+pushMeta (Meta mmap) = pushViaConstr' "Meta" [push mmap]
 
 peekMeta :: LuaError e => Peeker e Meta
 peekMeta idx = retrieving "Meta" $
diff --git a/src/Text/Pandoc/Lua/Module/Pandoc.hs b/src/Text/Pandoc/Lua/Module/Pandoc.hs
index 0a9ebaec5..84d6be360 100644
--- a/src/Text/Pandoc/Lua/Module/Pandoc.hs
+++ b/src/Text/Pandoc/Lua/Module/Pandoc.hs
@@ -15,6 +15,7 @@ module Text.Pandoc.Lua.Module.Pandoc
   ) where
 
 import Prelude hiding (read)
+import Control.Applicative (optional)
 import Control.Monad ((>=>), when)
 import Control.Monad.Except (throwError)
 import Data.Default (Default (..))
@@ -23,7 +24,7 @@ import HsLua as Lua hiding (pushModule)
 import HsLua.Class.Peekable (PeekError)
 import System.Exit (ExitCode (..))
 import Text.Pandoc.Class.PandocIO (runIO)
-import Text.Pandoc.Definition (Block, Inline)
+import Text.Pandoc.Definition
 import Text.Pandoc.Lua.Filter (SingletonsList (..), walkInlines,
                                walkInlineLists, walkBlocks, walkBlockLists)
 import Text.Pandoc.Lua.Marshaling ()
@@ -51,6 +52,8 @@ pushModule = do
   addFunction "pipe" pipe
   addFunction "walk_block" (walkElement peekBlock pushBlock)
   addFunction "walk_inline" (walkElement peekInline pushInline)
+  -- Constructors
+  addFunction "Pandoc" mkPandoc
   return 1
 
 walkElement :: (Walkable (SingletonsList Inline) a,
@@ -142,3 +145,12 @@ pushPipeError pipeErr = do
           , if output == mempty then BSL.pack "<no output>" else output
           ]
         return (NumResults 1)
+
+mkPandoc :: PandocLua NumResults
+mkPandoc = liftPandocLua $ do
+  doc <- forcePeek $ do
+    blks <- peekBlocks (nthBottom 1)
+    mMeta <- optional $ peekMeta (nthBottom 2)
+    pure $ Pandoc (fromMaybe nullMeta mMeta) blks
+  pushPandoc doc
+  return 1