Added json format for reading and writing.

This is faster to parse than native.

3 files changed, 19 insertions, 5 deletions

diff --git a/README b/README
index 91ec5e70b..26859a81d 100644
--- a/README
+++ b/README
@@ -140,8 +140,8 @@ Options
 =======
 
 `-f` *FORMAT*, `-r` *FORMAT*, `--from=`*FORMAT*, `--read=`*FORMAT*
-:   Specify input format.  *FORMAT* can be
-    `native` (native Haskell), `markdown` (markdown or plain text),
+:   Specify input format.  *FORMAT* can be `native` (native Haskell),
+    `json` (JSON version of native AST), `markdown` (markdown),
     `textile` (Textile), `rst` (reStructuredText), `html` (HTML),
     or `latex` (LaTeX).  If `+lhs` is appended to `markdown`, `rst`,
     or `latex`, the input will be treated as literate Haskell source:
@@ -150,7 +150,8 @@ Options
 
 `-t` *FORMAT*, `-w` *FORMAT*, `--to=`*FORMAT*, `--write=`*FORMAT*
 :   Specify output format.  *FORMAT* can be `native` (native Haskell),
-    `plain` (plain text), `markdown` (markdown), `rst` (reStructuredText),
+    `json` (JSON version of native AST), `plain` (plain text),
+    `markdown` (markdown), `rst` (reStructuredText),
     `html` (HTML), `latex` (LaTeX), `context` (ConTeXt), `man` (groff man), 
     `mediawiki` (MediaWiki markup), `textile` (Textile), `org` (Emacs
     Org-Mode), `texinfo` (GNU Texinfo), `docbook` (DocBook XML),
diff --git a/pandoc.cabal b/pandoc.cabal
index 0be9f27bf..c2cc7268a 100644
--- a/pandoc.cabal
+++ b/pandoc.cabal
@@ -167,7 +167,8 @@ Library
                  HTTP >= 4000.0.5, texmath >= 0.4, xml >= 1.3.5 && < 1.4,
                  random, extensible-exceptions,
                  citeproc-hs >= 0.3 && < 0.4,
-                 pandoc-types == 1.7.*
+                 pandoc-types == 1.7.*,
+                 json >= 0.4 && < 0.5
   if impl(ghc >= 6.10)
     Build-depends: base >= 4 && < 5, syb
   else
@@ -238,7 +239,8 @@ Executable pandoc
                  HTTP >= 4000.0.5, texmath, xml >= 1.3.5 && < 1.4,
                  random, extensible-exceptions,
                  citeproc-hs >= 0.3 && < 0.4,
-                 pandoc-types == 1.7.*
+                 pandoc-types == 1.7.*,
+                 json >= 0.4 && < 0.5
   if impl(ghc >= 6.10)
     Build-depends: base >= 4 && < 5, syb
   else
diff --git a/src/pandoc.hs b/src/pandoc.hs
index 3aa9a4ba8..e8220de34 100644
--- a/src/pandoc.hs
+++ b/src/pandoc.hs
@@ -29,6 +29,7 @@ Parses command-line options and calls the appropriate readers and
 writers.
 -}
 module Main where
+import Text.JSON.Generic (encodeJSON, decodeJSON)
 import Text.Pandoc
 import Text.Pandoc.S5 (s5HeaderIncludes)
 import Text.Pandoc.Shared ( tabFilter, ObfuscationMethod (..), readDataFile,
@@ -83,6 +84,7 @@ wrapWords c = wrap' c c where
 -- | Association list of formats and readers.
 readers :: [(String, ParserState -> String -> Pandoc)]
 readers = [("native"       , readPandoc)
+          ,("json"         , readJSON)
           ,("markdown"     , readMarkdown)
           ,("markdown+lhs" , readMarkdown)
           ,("rst"          , readRST)
@@ -97,9 +99,18 @@ readers = [("native"       , readPandoc)
 readPandoc :: ParserState -> String -> Pandoc
 readPandoc _ = read
 
+-- | Reader for JSON version of Pandoc AST.
+readJSON :: ParserState -> String -> Pandoc
+readJSON _ = decodeJSON
+
+-- | Writer for JSON version of Pandoc AST.
+writeJSON :: WriterOptions -> Pandoc -> String
+writeJSON _ = encodeJSON
+
 -- | Association list of formats and writers.
 writers :: [ ( String, WriterOptions -> Pandoc -> String ) ]
 writers = [("native"       , writeNative)
+          ,("json"         , writeJSON)
           ,("html"         , writeHtmlString)
           ,("html+lhs"     , writeHtmlString)
           ,("s5"           , writeHtmlString)