Convert tool/extract-changes.hs to a Lua filter.

2 files changed, 18 insertions, 15 deletions

diff --git a/tools/extract-changes.hs b/tools/extract-changes.hs
deleted file mode 100755
index d0ef35888..000000000
--- a/tools/extract-changes.hs
+++ /dev/null
@@ -1,15 +0,0 @@
-#!/usr/bin/env stack
--- stack --stack-yaml=stack.yaml runghc --package pandoc-types
-
--- Extract changes from latest version in changelog.
-import Text.Pandoc.JSON
-
-main = toJSONFilter extractFirst
-
-extractFirst :: Pandoc -> Pandoc
-extractFirst (Pandoc meta bs) =
-  let bs' = dropWhile (not . isSubhead) bs
-   in Pandoc meta (takeWhile (not . isSubhead) (drop 1 bs'))
-
-isSubhead (Header 2 _ _) = True
-isSubhead _ = False
diff --git a/tools/extract-changes.lua b/tools/extract-changes.lua
new file mode 100644
index 000000000..5d19c8d03
--- /dev/null
+++ b/tools/extract-changes.lua
@@ -0,0 +1,18 @@
+-- Extract changes from latest version in changelog.
+
+function Pandoc(el)
+  local newblocks = {}
+  i = 1
+  while i <= #el.blocks and
+      not (el.blocks[i].t == "Header" and el.blocks[i].level == 2) do
+    i = i+1
+  end
+  while i <= #el.blocks do
+    i = i+1
+    if el.blocks[i].t == "Header" and el.blocks[i].level == 2 then
+      break
+    end
+    table.insert(newblocks, el.blocks[i])
+  end
+  return pandoc.Pandoc(newblocks)
+end