depth 1 replace

filter.lua

@@ -1,3 +1,11 @@
+local label_map = {}               -- label has to be unique!
+
+local function collect_labels(div) -- only collect labels in div
+    if div.identifier and div.identifier ~= "" then
+        label_map[div.identifier] = div:clone()
+    end
+    return nil
+end
 
 local function words(s)
     local res = {}
@@ -10,27 +18,36 @@ local function words(s)
     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 function replace(e)
     local include = e.attributes["include"]
     if include then
-        local blocks = label2Block(include)
+        local blocks = {}
         -- Replace the Div contents
+        for _, l in ipairs(words(include)) do
+            if label_map[l] then
+                table.insert(blocks, label_map[l]:clone())
+                io.stderr:write("insert [" .. label_map[l].identifier .. ']\n')
+            else
+                io.stderr:write("Cannot find AST node with label " .. l)
+            end
+        end
         return pandoc.Div(blocks, e.attr)
     end
-    return nil -- no change
+    return e -- no change
 end
+
+return {
+    -- traverse = 'topdown',
+    Pandoc = function(doc)
+        -- collect labels
+        for _, blk in ipairs(doc.blocks) do
+            collect_labels(blk)
+        end
+
+        -- replace
+        for i, blk in ipairs(doc.blocks) do
+            doc.blocks[i] = replace(blk)
+        end
+        return doc
+    end
+}