6528082 · typeable/pandoc

git.iko.soy/typeable/pandoc

Lua filters: improve error messages

Provide more context about the task which caused an error.

commit6528082401100cd8ef26c8dc3e953b960a997827 authorAlbert Krewinkel <albert@zeitkraut.de> dateFri 12 Jan 2018, 21:26 (9 years ago) parentf130109

5 files changed+45−15

compare with master

unifiedsplit

pandoc.cabal+1 src/Text/Pandoc/Lua/Filter.hs+6−2 src/Text/Pandoc/Lua/StackInstances.hs+19−13 src/Text/Pandoc/Lua/Util.hs+9 test/Tests/Lua.hs+10

pandoc.cabal+1

@@ -347,6 +347,7 @@ library

347347 unordered-containers >= 0.2 && < 0.3,

348348 parsec >= 3.1 && < 3.2,

349349 mtl >= 2.2 && < 2.3,

350+ exceptions >= 0.8 && < 0.9,

350351 filepath >= 1.1 && < 1.5,

351352 process >= 1.2.3 && < 1.7,

352353 directory >= 1 && < 1.4,

src/Text/Pandoc/Lua/Filter.hs+6−2

@@ -11,6 +11,7 @@ module Text.Pandoc.Lua.Filter ( LuaFilterFunction

1111 , inlineElementNames

1212 ) where

1313import Control.Monad (mplus, unless, when, (>=>))

14+import Control.Monad.Catch (finally)

1415import Text.Pandoc.Definition

1516import Data.Foldable (foldrM)

1617import Data.Map (Map)

@@ -22,6 +23,7 @@ import Text.Pandoc.Walk (walkM, Walkable)

2223import Data.Data (Data, DataType, dataTypeConstrs, dataTypeName, dataTypeOf,

2324 showConstr, toConstr, tyconUQname)

2425import Text.Pandoc.Lua.StackInstances()

26+import Text.Pandoc.Lua.Util (typeCheck)

2527

2628type FunctionMap = Map String LuaFilterFunction

2729

@@ -65,7 +67,7 @@ registerFilterFunction idx = do

6567

6668elementOrList :: FromLuaStack a => a -> Lua [a]

6769elementOrList x = do

68− let topOfStack = Lua.StackIndex (-1)

70+ let topOfStack = Lua.stackTop

6971 elementUnchanged <- Lua.isnil topOfStack

7072 if elementUnchanged

7173 then [x] <$ Lua.pop 1

@@ -73,7 +75,9 @@ elementOrList x = do

7375 mbres <- Lua.peekEither topOfStack

7476 case mbres of

7577 Right res -> [res] <$ Lua.pop 1

76− Left _ -> Lua.toList topOfStack <* Lua.pop 1

78+ Left _ -> do

79+ typeCheck Lua.stackTop Lua.TypeTable

80+ Lua.toList topOfStack `finally` Lua.pop 1

7781

7882-- | Try running a filter for the given element

7983tryFilter :: (Data a, FromLuaStack a, ToLuaStack a)

src/Text/Pandoc/Lua/StackInstances.hs+19−13

@@ -35,13 +35,15 @@ module Text.Pandoc.Lua.StackInstances () where

3535

3636import Control.Applicative ((<|>))

3737import Control.Monad (when)

38+import Control.Monad.Catch (finally)

3839import Data.Data (showConstr, toConstr)

3940import Data.Foldable (forM_)

4041import Foreign.Lua (FromLuaStack (peek), Lua, LuaInteger, LuaNumber, StackIndex,

4142 ToLuaStack (push), Type (..), throwLuaError, tryLua)

4243import Text.Pandoc.Definition

4344import Text.Pandoc.Extensions (Extensions)

44−import Text.Pandoc.Lua.Util (adjustIndexBy, getTable, pushViaConstructor)

45+import Text.Pandoc.Lua.Util (adjustIndexBy, getTable, pushViaConstructor,

46+ typeCheck)

4547import Text.Pandoc.Options (ReaderOptions (..), TrackChanges)

4648import Text.Pandoc.Shared (Element (Blk, Sec), safeRead)

4749

@@ -49,21 +51,27 @@ import qualified Foreign.Lua as Lua

4951import qualified Data.Set as Set

5052import qualified Text.Pandoc.Lua.Util as LuaUtil

5153

54+defineHowTo :: String -> Lua a -> Lua a

55+defineHowTo ctx op = op `Lua.modifyLuaError` (("Could not " ++ ctx ++ ": ") ++)

56+

5257instance ToLuaStack Pandoc where

5358 push (Pandoc meta blocks) =

5459 pushViaConstructor "Pandoc" blocks meta

5560

5661instance FromLuaStack Pandoc where

57− peek idx = do

62+ peek idx = defineHowTo "get Pandoc value" $ do

63+ typeCheck idx Lua.TypeTable

5864 blocks <- getTable idx "blocks"

59− meta <- getTable idx "meta"

65+ meta <- Lua.getfield idx "meta" *> (Lua.peek Lua.stackTop `finally` Lua.pop 1)

6066 return $ Pandoc meta blocks

6167

6268instance ToLuaStack Meta where

6369 push (Meta mmap) =

6470 pushViaConstructor "Meta" mmap

6571instance FromLuaStack Meta where

66− peek idx = Meta <$> peek idx

72+ peek idx = defineHowTo "get Meta value" $ do

73+ typeCheck idx Lua.TypeTable

74+ Meta <$> peek idx

6775

6876instance ToLuaStack MetaValue where

6977 push = pushMetaValue

@@ -160,7 +168,7 @@ pushMetaValue = \case

160168

161169-- | Interpret the value at the given stack index as meta value.

162170peekMetaValue :: StackIndex -> Lua MetaValue

163−peekMetaValue idx = do

171+peekMetaValue idx = defineHowTo "get MetaValue" $ do

164172 -- Get the contents of an AST element.

165173 let elementContent :: FromLuaStack a => Lua a

166174 elementContent = peek idx

@@ -209,7 +217,8 @@ pushBlock = \case

209217

210218-- | Return the value at the given index as block if possible.

211219peekBlock :: StackIndex -> Lua Block

212−peekBlock idx = do

220+peekBlock idx = defineHowTo "get Block value" $ do

221+ typeCheck idx Lua.TypeTable

213222 tag <- getTag idx

214223 case tag of

215224 "BlockQuote" -> BlockQuote <$> elementContent

@@ -260,7 +269,8 @@ pushInline = \case

260269

261270-- | Return the value at the given index as inline if possible.

262271peekInline :: StackIndex -> Lua Inline

263−peekInline idx = do

272+peekInline idx = defineHowTo "get Inline value" $ do

273+ typeCheck idx Lua.TypeTable

264274 tag <- getTag idx

265275 case tag of

266276 "Cite" -> uncurry Cite <$> elementContent

@@ -296,11 +306,7 @@ getTag idx = do

296306 hasMT <- Lua.getmetatable idx

297307 push "tag"

298308 if hasMT then Lua.rawget (-2) else Lua.rawget (idx `adjustIndexBy` 1)

299− r <- tryLua (peek (-1))

300− Lua.settop top

301− case r of

302− Left (Lua.LuaException err) -> throwLuaError err

303− Right res -> return res

309+ peek Lua.stackTop `finally` Lua.settop top

304310

305311withAttr :: (Attr -> a -> b) -> (LuaAttr, a) -> b

306312withAttr f (attributes, x) = f (fromLuaAttr attributes) x

@@ -313,7 +319,7 @@ instance ToLuaStack LuaAttr where

313319 pushViaConstructor "Attr" id' classes kv

314320

315321instance FromLuaStack LuaAttr where

316− peek idx = LuaAttr <$> peek idx

322+ peek idx = defineHowTo "get Attr value" (LuaAttr <$> peek idx)

317323

318324--

319325-- Hierarchical elements

src/Text/Pandoc/Lua/Util.hs+9

@@ -36,6 +36,7 @@ module Text.Pandoc.Lua.Util

3636 , getRawInt

3737 , setRawInt

3838 , addRawInt

39+ , typeCheck

3940 , raiseError

4041 , popValue

4142 , PushViaCall

@@ -100,6 +101,14 @@ setRawInt idx key value = do

100101addRawInt :: ToLuaStack a => Int -> a -> Lua ()

101102addRawInt = setRawInt (-1)

102103

104+typeCheck :: StackIndex -> Lua.Type -> Lua ()

105+typeCheck idx expected = do

106+ actual <- Lua.ltype idx

107+ when (actual /= expected) $ do

108+ expName <- Lua.typename expected

109+ actName <- Lua.typename actual

110+ Lua.throwLuaError $ "expected " ++ expName ++ " but got " ++ actName ++ "."

111+

103112raiseError :: ToLuaStack a => a -> Lua NumResults

104113raiseError e = do

105114 Lua.push e

test/Tests/Lua.hs+10

@@ -123,6 +123,16 @@ tests = map (localOption (QuickCheckTests 20))

123123 Lua.getglobal "PANDOC_API_VERSION"

124124 Lua.liftIO . assertEqual "pandoc-types version is wrong" versionNums

125125 =<< Lua.peek Lua.stackTop

126+

127+ , testCase "informative error messages" . runPandocLua' $ do

128+ Lua.pushboolean True

129+ err <- Lua.peekEither Lua.stackTop :: Lua.Lua (Either String Pandoc)

130+ case err of

131+ Left msg -> do

132+ let expectedMsg = "Could not get Pandoc value: "

133+ ++ "expected table but got boolean."

134+ Lua.liftIO $ assertEqual "unexpected error message" expectedMsg msg

135+ Right _ -> error "Getting a Pandoc element from a bool should fail."

126136 ]

127137

128138assertFilterConversion :: String -> FilePath -> Pandoc -> Pandoc -> Assertion