1 files changed, 138 insertions, 0 deletions
diff --git a/paper/lua-filters/section-refs/section-refs.lua b/paper/lua-filters/section-refs/section-refs.lua
new file mode 100644
index 0000000..68e61d0
--- /dev/null
+++ b/paper/lua-filters/section-refs/section-refs.lua
@@ -0,0 +1,138 @@
+function is_ref_div (blk)
+   return (blk.t == "Div" and blk.identifier == "refs")
+end
+
+function is_ref_header (blk)
+   return (blk.t == "Header" and blk.identifier == "bibliography")
+end
+
+function get_all_refs (blks)
+   for _, b in pairs(blks) do
+      if is_ref_div(b) then
+	 return b.content
+      end
+   end
+end
+
+function remove_all_refs (blks)
+   local out = {}
+   for _, b in pairs(blks) do
+      if not (is_ref_div(b) or is_ref_header(b)) then
+	 table.insert(out, b)
+      end
+   end
+   return out
+end
+
+-- We return a {number, ref} pair so we can sort in the individual
+-- bibliographies.
+function citation_to_numbered_ref (citation, all_refs)
+   local div_id = "ref-" .. citation.id
+   for i, d in ipairs(all_refs) do
+      if d.t == "Div" and d.identifier == div_id then
+	 return {i, d}
+      end
+   end
+end
+
+
+function get_partial_refs (blocks, all_refs)
+   local cites = {}
+   local citegetter = {
+      Cite = function (el)
+	 for _, c in pairs(el.citations) do
+	    table.insert(cites, c)
+	 end
+      end
+   }
+
+   for _, b in pairs(blocks) do
+      pandoc.walk_block(b, citegetter)
+   end
+
+
+   -- first we make a list of the {number, ref} pairs so we can sort
+   -- them. Then after sorting, we're going to make a new list with
+   -- only the second element.
+   local numbered_refs = {}
+   for _, c in pairs(cites) do
+      local r = citation_to_numbered_ref(c, all_refs)
+      if r then
+	 table.insert(numbered_refs, r)
+      end
+   end
+
+   table.sort(numbered_refs, function(x, y) return x[1] < y[1] end)
+
+   local refs = {}
+   for _, nr in pairs(numbered_refs) do
+      table.insert(refs, nr[2])
+   end
+
+   return refs
+end
+
+function add_section_refs (blks, lvl, refs_title, all_refs)
+   local output_blks = {}
+   local section = {}
+   local refs_num = 0
+
+   local go = function ()
+      refs_num = refs_num + 1
+      local section_refs = get_partial_refs(section, all_refs)
+      if refs_title then
+	 local hdr = pandoc.Header(lvl + 1,
+				   refs_title,
+				   pandoc.Attr("bibliography-" .. tostring(refs_num),
+					       {"unnumbered"}))
+	 table.insert(section_refs, 1, hdr)
+      end
+      local refs_div = pandoc.Div(section_refs,
+				  pandoc.Attr("refs-" .. tostring(refs_num),
+					      {"references"}))
+      table.insert(section, refs_div)
+      for _, x in pairs(section) do
+	 table.insert(output_blks, x)
+      end
+   end
+
+   -- to avoid putting a bib after an intro paragraph.
+   local seen_hdr_before = false
+   for _, b in pairs(blks) do
+      if b.t == "Header" and b.level <= lvl then
+	 if seen_hdr_before then
+	    go()
+	    section = {b}
+	 else
+	    seen_hdr_before = true
+	    table.insert(section, b)
+	 end
+      else
+	 table.insert(section, b)
+      end
+   end
+   go()
+   return output_blks
+end
+
+function Pandoc(doc)
+   if PANDOC_VERSION == nil then -- if pandoc_version < 2.1
+      io.stderr:write("WARNING: pandoc >= 2.1 required for section-refs filter\n")
+      return doc
+   end
+   local refs_title = doc.meta["reference-section-title"]
+   -- if we get it from a command-line field, read it in as md.
+   if type(refs_title) == "string" then
+      refs_title = pandoc.read(refs_title, "markdown").blocks[1].content
+   end
+   local lvl = tonumber(doc.meta["section-refs-level"]) or 1
+   local all_refs = get_all_refs(doc.blocks)
+   -- we only want to do something if there are refs to work
+   -- with. This way, if this is run without pandoc-citeproc, it will
+   -- just return the same document.
+   if all_refs then
+      local unreffed = remove_all_refs(doc.blocks)
+      local output = add_section_refs(unreffed, lvl, refs_title, all_refs)
+      return pandoc.Pandoc(output, doc.meta)
+   end
+end