includes multiple files

output.html

@@ -1,8 +1,12 @@
-<p>Here’s the pandoc README:</p>
-<div class="sourceCode" id="cb1" data-include="filter.hs"
-style="background-color: red"><pre
-class="sourceCode haskell"><code class="sourceCode haskell"><span id="cb1-1"><a href="#cb1-1" aria-hidden="true" tabindex="-1"></a><span class="dt">Foo</span><span class="ot">::</span> <span class="dt">Div</span> <span class="ot">-&gt;</span> <span class="dt">Div</span></span></code></pre></div>
-<div data-include="filter.hs">
+<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Fusce porta
+mattis neque, quis molestie nunc faucibus vitae. Phasellus vel commodo
+dolor, at faucibus arcu. Curabitur sit amet magna a neque euismod
+feugiat non et diam. Aliquam sit amet libero enim. Integer dignissim
+ullamcorper felis, ac ultrices turpis congue vel. Nulla id tempus orci.
+Curabitur ac vulputate tellus. Integer fermentum tempor facilisis. Duis
+egestas luctus tristique. Maecenas vitae arcu sit amet justo feugiat
+imperdiet. Nunc luctus erat sed ligula convallis hendrerit.</p>
+<div data-include="filter.hs , filter.lua , ,">
 #!/usr/bin/env runhaskell
 -- filter.hs
 import Text.Pandoc.JSON
@@ -24,6 +28,44 @@ doInclude x = return x
 
 main :: IO ()
 main = toJSONFilter doInclude
+local function words(s)
+    local res = {}
+    for part in s:gmatch("[^,]+") do                -- split by commas
+        local trimmed = part:match("^%s*(.-)%s*$")  -- remove
+leading/trailing spaces
+        if trimmed ~= "" then
+            table.insert(res, trimmed)
+        end
+    end
+    return res
+end
+
+local function label2Block(labels)
+    local contents = ""
+    for _,l in ipairs(words(labels)) do
+        -- use file for now.
+        local fh = io.open(l, "r")
+        if not fh then
+            io.stderr:write("Cannot open file: " .. l .. "\n")
+            return { pandoc.Plain { pandoc.Str("[Error: cannot read file
+" .. l .. "]") } }
+        end
+        contents = contents .. fh:read("*a")
+        fh:close()
+    end
+    return { pandoc.Plain { pandoc.Str(contents) } }
+end
+
+function Div(e)
+    local include = e.attributes["include"]
+    if include then
+        local blocks = label2Block(include)
+        -- Replace the Div contents
+        return pandoc.Div(blocks, e.attr)
+    end
+    return nil -- no change
+end
+
 </div>
 <div class="Theorem">
 <p>test thm1</p>
@@ -34,3 +76,7 @@ main = toJSONFilter doInclude
 <div id="thm3" class="Theorem">
 <p>test thm3</p>
 </div>
+<div id="special" class="sidebar">
+<p>Here is a paragraph.</p>
+<p>And another.</p>
+</div>