Shake.hs, tools/pandoc-demote-headers: switch to lua script filter

Shake.hs

@@ -82,8 +82,8 @@ main = do
 --    <$> S.getDirectoryContents "tools"
   let pandocFilters =
         [
-         "tools" </> "pandoc-demote-headers"
-        ,"tools" </> "pandoc-drop-html-blocks"
+        --- "tools" </> "pandoc-demote-headers"
+         "tools" </> "pandoc-drop-html-blocks"
         ,"tools" </> "pandoc-drop-html-inlines"
         ,"tools" </> "pandoc-drop-links"
         ,"tools" </> "pandoc-drop-notes"
@@ -273,7 +273,7 @@ main = do
       cmd Shell
         "m4 -P -DMAN -DWEB -I" dir lib src "|"
         pandoc "-f markdown -t markdown-fenced_divs --atx-headers"
-        "--filter tools/pandoc-demote-headers"
+        "--lua-filter tools/pandoc-demote-headers.lua"
         -- "--filter tools/pandoc-add-toc"
         -- "--filter tools/pandoc-drop-man-blocks"
         ">>" out
@@ -290,7 +290,7 @@ main = do
           -- "--filter tools/pandoc-drop-man-blocks"
           "--filter tools/pandoc-drop-toc"
           -- "--filter tools/pandoc-capitalize-headers"
-          "--filter tools/pandoc-demote-headers"
+          "--lua-filter tools/pandoc-demote-headers.lua"
           ">>" webmanall :: Action ExitCode
 
     -- adjust and combine recipe mds for single-page web output, using pandoc

tools/pandoc-demote-headers.hs

@@ -1,14 +0,0 @@
-#!/usr/bin/env stack
-{- stack runghc --verbosity info --package pandoc-types -}
-
-import Text.Pandoc.JSON
-import Text.Pandoc.Walk
-import Data.Char (toUpper)
-
-main :: IO ()
-main = toJSONFilter demoteHeaders
-
-demoteHeaders :: Block -> Block
-demoteHeaders (Header l attr xs) = Header (l+1) attr xs
-demoteHeaders x = x
-

tools/pandoc-demote-headers.lua

@@ -0,0 +1,3 @@
+function Header(h)
+    return pandoc.Header(h.level + 1, h.content, h.attrs)
+end