doc/lua-filters.md: document pandoc.write_classic.

1 files changed, 30 insertions, 0 deletions

diff --git a/doc/lua-filters.md b/doc/lua-filters.md
index 6c772ae6a..619d4fe80 100644
--- a/doc/lua-filters.md
+++ b/doc/lua-filters.md
@@ -3543,6 +3543,36 @@ Usage:
     local html = pandoc.write(doc, 'html')
     assert(html == "<p><strong>Tea</strong></p>")
 
+### `write_classic (doc[, writer_options])` {#pandoc.write_custom}
+
+Runs a classic custom Lua writer, using the functions defined
+in the current environment.
+
+Parameters:
+
+`doc`
+:   document to convert ([Pandoc](#type-pandoc))
+
+`writer_options`
+:   options passed to the writer; may be a [WriterOptions] object
+    or a table with a subset of the keys and values of a
+    WriterOptions object; defaults to the default values
+    documented in the manual. ([WriterOptions]|table)
+
+Returns:
+-   converted document (string)
+
+Usage:
+
+    -- Adding this function converts a classic writer into a
+    -- new-style custom writer.
+    function Writer (doc, opts)
+      PANDOC_DOCUMENT = doc
+      PANDOC_WRITER_OPTIONS = opts
+      loadfile(PANDOC_SCRIPT_FILE)()
+      return pandoc.write_classic(doc, opts)
+    end
+
 [WriterOptions]: #type-writeroptions
 
 # Module pandoc.utils