Pandoc 2.11 compatibility (#826)

* Pandoc 2.11 compatibility

* Bump stack.yaml

* Bump stack dependencies

5 files changed, 123 insertions, 86 deletions

diff --git a/hakyll.cabal b/hakyll.cabal
index a3c0cc3..94bbab8 100644
--- a/hakyll.cabal
+++ b/hakyll.cabal
@@ -232,8 +232,7 @@ Library
     Other-Modules:
       Hakyll.Web.Pandoc.Binary
     Build-Depends:
-      pandoc          >= 2.10     && < 2.12,
-      pandoc-citeproc >= 0.14     && < 0.18
+      pandoc >= 2.11 && < 2.12
     Cpp-options:
       -DUSE_PANDOC
 
@@ -327,4 +326,4 @@ Executable hakyll-website
     base      >= 4     && < 5,
     directory >= 1.0   && < 1.4,
     filepath  >= 1.0   && < 1.5,
-    pandoc    >= 2.10  && < 2.12
+    pandoc    >= 2.11  && < 2.12
diff --git a/lib/Hakyll/Web/Pandoc/Biblio.hs b/lib/Hakyll/Web/Pandoc/Biblio.hs
index 5127d88..567f478 100644
--- a/lib/Hakyll/Web/Pandoc/Biblio.hs
+++ b/lib/Hakyll/Web/Pandoc/Biblio.hs
@@ -12,6 +12,7 @@
 {-# LANGUAGE Arrows                     #-}
 {-# LANGUAGE DeriveDataTypeable         #-}
 {-# LANGUAGE GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE OverloadedStrings          #-}
 module Hakyll.Web.Pandoc.Biblio
     ( CSL
     , cslCompiler
@@ -23,33 +24,31 @@ module Hakyll.Web.Pandoc.Biblio
 
 
 --------------------------------------------------------------------------------
-import           Control.Monad            (liftM, replicateM)
-import           Data.Binary              (Binary (..))
-import           Data.Typeable            (Typeable)
+import           Control.Monad                 (liftM)
+import           Data.Binary                   (Binary (..))
+import qualified Data.ByteString               as B
+import qualified Data.ByteString.Lazy          as BL
+import qualified Data.Map                      as Map
+import qualified Data.Time                     as Time
+import           Data.Typeable                 (Typeable)
 import           Hakyll.Core.Compiler
 import           Hakyll.Core.Compiler.Internal
 import           Hakyll.Core.Identifier
 import           Hakyll.Core.Item
-import           Hakyll.Core.Provider
 import           Hakyll.Core.Writable
 import           Hakyll.Web.Pandoc
-import           Hakyll.Web.Pandoc.Binary ()
-import qualified Text.CSL                 as CSL
-import           Text.CSL.Pandoc          (processCites)
-import           Text.Pandoc              (Pandoc, ReaderOptions (..),
-                                           enableExtension, Extension (..))
+import           Text.Pandoc                   (Extension (..), Pandoc,
+                                                ReaderOptions (..),
+                                                enableExtension)
+import qualified Text.Pandoc                   as Pandoc
+import qualified Text.Pandoc.Citeproc          as Pandoc (processCitations)
 
 
 --------------------------------------------------------------------------------
-data CSL = CSL
-    deriving (Show, Typeable)
+newtype CSL = CSL {unCSL :: B.ByteString}
+    deriving (Binary, Show, Typeable)
 
 
---------------------------------------------------------------------------------
-instance Binary CSL where
-    put CSL = return ()
-    get     = return CSL
-
 
 --------------------------------------------------------------------------------
 instance Writable CSL where
@@ -59,21 +58,12 @@ instance Writable CSL where
 
 --------------------------------------------------------------------------------
 cslCompiler :: Compiler (Item CSL)
-cslCompiler = makeItem CSL
-
-
---------------------------------------------------------------------------------
-newtype Biblio = Biblio [CSL.Reference]
-    deriving (Show, Typeable)
+cslCompiler = fmap (CSL . BL.toStrict) <$> getResourceLBS
 
 
 --------------------------------------------------------------------------------
-instance Binary Biblio where
-    -- Ugly.
-    get             = do
-        len <- get
-        Biblio <$> replicateM len get
-    put (Biblio rs) = put (length rs) >> mapM_ put rs
+newtype Biblio = Biblio {unBiblio :: B.ByteString}
+    deriving (Binary, Show, Typeable)
 
 
 --------------------------------------------------------------------------------
@@ -84,12 +74,7 @@ instance Writable Biblio where
 
 --------------------------------------------------------------------------------
 biblioCompiler :: Compiler (Item Biblio)
-biblioCompiler = do
-    filePath <- getResourceFilePath
-    makeItem =<< unsafeCompiler (Biblio <$> CSL.readBiblioFile idpred filePath)
-  where
-    -- This is a filter on citations.  We include all citations.
-    idpred = const True
+biblioCompiler = fmap (Biblio . BL.toStrict) <$> getResourceLBS
 
 
 --------------------------------------------------------------------------------
@@ -99,19 +84,42 @@ readPandocBiblio :: ReaderOptions
                  -> (Item String)
                  -> Compiler (Item Pandoc)
 readPandocBiblio ropt csl biblio item = do
-    -- Parse CSL file, if given
-    provider <- compilerProvider <$> compilerAsk
-    style <- unsafeCompiler $
-             CSL.readCSLFile Nothing . (resourceFilePath provider) . itemIdentifier $ csl
-
-    -- We need to know the citation keys, add then *before* actually parsing the
-    -- actual page. If we don't do this, pandoc won't even consider them
-    -- citations!
-    let Biblio refs = itemBody biblio
-    pandoc <- itemBody <$> readPandocWith ropt item
-    let pandoc' = processCites style refs pandoc
-
-    return $ fmap (const pandoc') item
+    -- It's not straightforward to use the Pandoc API as of 2.11 to deal with
+    -- citations, since it doesn't export many things in 'Text.Pandoc.Citeproc'.
+    -- The 'citeproc' package is also hard to use.
+    --
+    -- So instead, we try treating Pandoc as a black box.  Pandoc can read
+    -- specific csl and bilbio files based on metadata keys.
+    --
+    -- So we load the CSL and Biblio files and pass them to Pandoc using the
+    -- ersatz filesystem.
+    Pandoc.Pandoc (Pandoc.Meta meta) blocks <- itemBody <$>
+        readPandocWith ropt item
+
+    let cslFile = Pandoc.FileInfo zeroTime . unCSL $ itemBody csl
+        bibFile = Pandoc.FileInfo zeroTime . unBiblio $ itemBody biblio
+        addBiblioFiles = \st -> st
+            { Pandoc.stFiles =
+                Pandoc.insertInFileTree "_hakyll/style.csl" cslFile .
+                Pandoc.insertInFileTree "_hakyll/refs.bib" bibFile $
+                Pandoc.stFiles st
+            }
+        biblioMeta = Pandoc.Meta .
+            Map.insert "csl" (Pandoc.MetaString "_hakyll/style.csl") .
+            Map.insert "bibliography" (Pandoc.MetaString "_hakyll/refs.bib") $
+            meta
+        errOrPandoc = Pandoc.runPure $ do
+            Pandoc.modifyPureState addBiblioFiles
+            Pandoc.processCitations $ Pandoc.Pandoc biblioMeta blocks
+
+    pandoc <- case errOrPandoc of
+        Left  e -> compilerThrow ["Error during processCitations: " ++ show e]
+        Right x -> return x
+
+    return $ fmap (const pandoc) item
+
+  where
+    zeroTime = Time.UTCTime (toEnum 0) 0
 
 --------------------------------------------------------------------------------
 pandocBiblioCompiler :: String -> String -> Compiler (Item String)
diff --git a/lib/Hakyll/Web/Pandoc/Binary.hs b/lib/Hakyll/Web/Pandoc/Binary.hs
index 5d3efea..3f7f4fb 100644
--- a/lib/Hakyll/Web/Pandoc/Binary.hs
+++ b/lib/Hakyll/Web/Pandoc/Binary.hs
@@ -4,9 +4,6 @@ module Hakyll.Web.Pandoc.Binary where
 
 import           Data.Binary        (Binary (..))
 
-import qualified Text.CSL           as CSL
-import qualified Text.CSL.Reference as REF
-import qualified Text.CSL.Style     as STY
 import           Text.Pandoc
 
 --------------------------------------------------------------------------------
@@ -18,7 +15,6 @@ instance Binary Caption
 instance Binary Cell
 instance Binary ColSpan
 instance Binary ColWidth
-instance Binary CSL.Reference
 instance Binary Citation
 instance Binary CitationMode
 instance Binary Format
@@ -27,17 +23,9 @@ instance Binary ListNumberDelim
 instance Binary ListNumberStyle
 instance Binary MathType
 instance Binary QuoteType
-instance Binary REF.CLabel
-instance Binary REF.CNum
-instance Binary REF.Literal
-instance Binary REF.RefDate
-instance Binary REF.RefType
-instance Binary REF.Season
 instance Binary Row
 instance Binary RowHeadColumns
 instance Binary RowSpan
-instance Binary STY.Agent
-instance Binary STY.Formatted
 instance Binary TableBody
 instance Binary TableFoot
 instance Binary TableHead
diff --git a/stack.yaml b/stack.yaml
index 63ee6a4..7820738 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -1,5 +1,7 @@
 resolver: lts-16.21
 save-hackage-creds: false
+system-ghc: true
+skip-ghc-check: true
 
 flags:
   hakyll:
@@ -23,10 +25,15 @@ build:
   haddock-deps: false
 
 extra-deps:
-- 'commonmark-0.1.0.2'
-- 'commonmark-extensions-0.2.0.1'
+- 'citeproc-0.2'
+- 'commonmark-0.1.1.2'
+- 'commonmark-extensions-0.2.0.4'
 - 'commonmark-pandoc-0.2.0.1'
-- 'hslua-1.1.2'
+- 'hslua-1.3.0'
+- 'hslua-module-text-0.3.0.1'
 - 'jira-wiki-markup-1.3.2'
-- 'pandoc-2.10.1'
-- 'pandoc-types-1.21'
+- 'pandoc-2.11.2'
+- 'pandoc-types-1.22'
+- 'rfc5051-0.2'
+- 'skylighting-0.10.1'
+- 'skylighting-core-0.10.1'
diff --git a/stack.yaml.lock b/stack.yaml.lock
index 8636225..caab7e9 100644
--- a/stack.yaml.lock
+++ b/stack.yaml.lock
@@ -5,19 +5,26 @@
 
 packages:
 - completed:
-    hackage: commonmark-0.1.0.2@sha256:fbff7a2ade0ce7d699964a87f765e503a3a9e22542c05f0f02ba7aad64e38af4,3278
+    hackage: citeproc-0.2@sha256:72a6b976a1d3ff2107043cfeb942e278ce2b93f0e31752da86bc6431b862ae19,5431
+    pantry-tree:
+      size: 78527
+      sha256: 1dd0f1ee7bc43367fbb745ba859ad6e2eb3b8d16d515c47deba31a5bd09bc0e2
+  original:
+    hackage: citeproc-0.2
+- completed:
+    hackage: commonmark-0.1.1.2@sha256:c06ab05f0f224ab7982502a96e17952823a9b6dae8505fb35194b0baa9e2a975,3278
     pantry-tree:
       size: 1346
-      sha256: 991da6da60804286b9ea23a1522e18ceeabddfdf416787231db9fd047c163f53
+      sha256: 6a187bbbfaf61b4b1bf87ee5027e7edb5b7157ad3380982b07b876e9a60cd63d
   original:
-    hackage: commonmark-0.1.0.2
+    hackage: commonmark-0.1.1.2
 - completed:
-    hackage: commonmark-extensions-0.2.0.1@sha256:647aa8dba5fd46984ddedc15c3693c9c4d9655503d42006576bd8f0dadf8cd39,3176
+    hackage: commonmark-extensions-0.2.0.4@sha256:6a437bcfa3c757af4262b71336513619990eafb5cfdc33e57a499c93ad225608,3184
     pantry-tree:
-      size: 2927
-      sha256: 89e1ee05938d558834c397a3a22cdacc755a1941c144f4c1f3daf8a1ede943ce
+      size: 2928
+      sha256: ac8993e356edabc65a40d6c6909696c5f2dfe2a5298089da820c29ca75852360
   original:
-    hackage: commonmark-extensions-0.2.0.1
+    hackage: commonmark-extensions-0.2.0.4
 - completed:
     hackage: commonmark-pandoc-0.2.0.1@sha256:529c6e2c6cabf61558b66a28123eafc1d90d3324be29819f59f024e430312c1f,1105
     pantry-tree:
@@ -26,12 +33,19 @@ packages:
   original:
     hackage: commonmark-pandoc-0.2.0.1
 - completed:
-    hackage: hslua-1.1.2@sha256:6c231b2af447430d1ed04f065d40bb6882ece93cc7f32f4051dc99deb69beeae,9694
+    hackage: hslua-1.3.0@sha256:d9b758f6234286a7df267cae15332507a1d3be56baf03ff7ae073269bc55c4e8,11023
+    pantry-tree:
+      size: 7716
+      sha256: e2cc992f8ea4781718386c3c0def49f04be96b4b0c459b629df555b0c045efc2
+  original:
+    hackage: hslua-1.3.0
+- completed:
+    hackage: hslua-module-text-0.3.0.1@sha256:e245d7bf9746101664dcde9c33b1c8cd792d404fddb8d9346ae6abb6b971dd93,1741
     pantry-tree:
-      size: 6820
-      sha256: 62e61f6d08191159a070dcbaa20284a581835de620105a254dbee1c7ddfabd9d
+      size: 415
+      sha256: 70932f637ef2a81024d43270f3b28ce870d7b43c405fb399d51d07f170da76ea
   original:
-    hackage: hslua-1.1.2
+    hackage: hslua-module-text-0.3.0.1
 - completed:
     hackage: jira-wiki-markup-1.3.2@sha256:b5f0901208a0ee07aff60f5356aeb851b7aa7950c75a18a15fd34247a35886d8,3819
     pantry-tree:
@@ -40,19 +54,40 @@ packages:
   original:
     hackage: jira-wiki-markup-1.3.2
 - completed:
-    hackage: pandoc-2.10.1@sha256:23d7ec480c7cb86740475a419d6ca4819987b6dd23bbae9b50bc3d42a7ed2f9f,36933
+    hackage: pandoc-2.11.2@sha256:e21f0af1750c4d7a3cf9096c46403c55043c9ac06c7c37627ecb312499eb3136,39349
+    pantry-tree:
+      size: 114848
+      sha256: ef31f41960bd8ae1a1b02b2c56a692583398f2cb3fc7c0177583b698a6a60fdf
+  original:
+    hackage: pandoc-2.11.2
+- completed:
+    hackage: pandoc-types-1.22@sha256:15512ce011555ee720820f11cac0598317293406da5812337cbb1550d144e3bd,4071
+    pantry-tree:
+      size: 737
+      sha256: 28e43150f4bb0d4d880cf92ade20fefcd8705ee95cfe4a1d0bb5efd320982a9d
+  original:
+    hackage: pandoc-types-1.22
+- completed:
+    hackage: rfc5051-0.2@sha256:da5d77731f2ac6fe313a67919419b0833e09cd7f1a81869ed82a54dbf8962bf2,1678
+    pantry-tree:
+      size: 446
+      sha256: 191a30a13590a14dc8f606ff945298fee6afbb093a49bc5db71dbaf066f01930
+  original:
+    hackage: rfc5051-0.2
+- completed:
+    hackage: skylighting-0.10.1@sha256:69f9175c606289164347a2ae1507218bf0c2479a1ed93356d24e83e4097ef493,10031
     pantry-tree:
-      size: 89646
-      sha256: 08c8b20356152b9ee8161bacafda2dc1bed13d7db4cbf38ab040c1977b2d28d5
+      size: 10837
+      sha256: 5b5516a196a75c6dffb33c3c9227d743d3c48e3d659fb7aad2cc01609e1e3a1f
   original:
-    hackage: pandoc-2.10.1
+    hackage: skylighting-0.10.1
 - completed:
-    hackage: pandoc-types-1.21@sha256:b61ed625da4d1a0d8057fcca4c0c5e174c9f45d94b41504db1532f3fc581e945,4037
+    hackage: skylighting-core-0.10.1@sha256:da0b01c22322f1312e9a5e37343f2153a3a8ba65a3d88ef51cf9b1360c466e08,8159
     pantry-tree:
-      size: 713
-      sha256: e26eb93747538e29168032985a03b428039a16000fea1a4a8d9b9b032ac98b5f
+      size: 13517
+      sha256: 48673ab1725d2aa6c019bb8a7d1419002d9a86a5dd54e2745b9d78846d793b29
   original:
-    hackage: pandoc-types-1.21
+    hackage: skylighting-core-0.10.1
 snapshots:
 - completed:
     size: 532413