Add 'multibib-renumber.lua' filter

The initial version is just code that has been removed from
pandoc-ext#8.

Author: wlupton

_extensions/multibib/multibib-renumber.lua

@@ -0,0 +1,73 @@
+--[[
+multibib-renumber – renumber numbered references and their citations
+
+Copyright © 2018-2024 Albert Krewinkel
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+]]
+
+local pandoc = require 'pandoc'
+local List   = require 'pandoc.List'
+
+-- this filter should run after the multibib filter
+-- (the logic is too dependent on the CSL, although it should do no harm)
+
+-- map from reference id to its new label
+local ref_map = List()
+
+-- ref counter
+local ref_counter = 1
+
+local function collect_numbered_refs(div)
+  if div.attr.classes:includes('csl-entry') then
+    local identifier = div.attr.identifier
+    local content = div.content
+    -- expect single Para with a Span (depending on style) possibly containing
+    -- the citation number (only do anything if it does)
+    if (#div.content > 0 and #div.content[1].content > 0 and
+        div.content[1].content[1].tag == 'Span') then
+      local span = div.content[1].content[1]
+      local content = span.content
+      if #content > 0 then
+        local text = content[1].text
+        local pre, num, post = content[1].text:match("^(%p*)(%d+)(%p*)$")
+        if pre and num and post then
+          local ident = identifier:gsub('^ref%-', '')
+          local label = string.format('%s%d%s', pre, ref_counter, post)
+          content[1] = pandoc.Str(label)
+          ref_map[ident] = label
+          ref_counter = ref_counter + 1
+          return div
+        end
+      end
+    end
+  end
+end
+
+local function renumber_cites(cite)
+  -- only consider cites with single citations
+  if #cite.citations == 1 then
+    local id = cite.citations[1].id
+    local label = ref_map[id]
+    -- only change the content if the label is defined
+    if label then
+      cite.content = label
+      return cite
+    end
+  end
+end
+
+return {
+  { Div = collect_numbered_refs },
+  { Cite = renumber_cites }
+}

multibib-renumber.lua

@@ -0,0 +1 @@
+_extensions/multibib/multibib-renumber.lua

test/test.yaml

@@ -3,3 +3,4 @@ to: plain
 standalone: true
 filters:
   - multibib.lua
+  - multibib-renumber.lua