Write meta.json when generating html output (#676)

1 files changed, 22 insertions, 0 deletions

diff --git a/haddock-api/src/Haddock/Backends/Meta.hs b/haddock-api/src/Haddock/Backends/Meta.hs
new file mode 100644
index 00000000..c62c1ae8
--- /dev/null
+++ b/haddock-api/src/Haddock/Backends/Meta.hs
@@ -0,0 +1,22 @@
+module Haddock.Backends.Meta where
+
+import Haddock.Utils.Json
+import Haddock.Version
+
+import Data.ByteString.Builder (hPutBuilder)
+import System.FilePath ((</>))
+import System.IO (withFile, IOMode (WriteMode))
+
+-- | Writes a json encoded file containing additional
+-- information about the generated documentation. This
+-- is useful for external tools (e.g. hackage).
+writeHaddockMeta :: FilePath -> IO ()
+writeHaddockMeta odir = do
+  let
+    meta_json :: Value
+    meta_json = object [
+        "haddock_version" .= String projectVersion
+      ]
+
+  withFile (odir </> "meta.json") WriteMode $ \h ->
+    hPutBuilder h (encodeToBuilder meta_json)
\ No newline at end of file