feat(packages): Biblatex data inheritance and field mapping

Add (a part of) the BibLaTeX data inheritance rules for
cross-references.
Use BibLaTeX field names, but still support the legacy
BibTeX file names.
As part of these refactors, allow loading more than one
bibliography file.

Author: Omikhleia

packages/bibtex/bibmaps.lua

@@ -0,0 +1,60 @@
+-- Mappings for aliases and inheritance rules
+
+-- Partial implementation of the Biber/BibLaTeX data inheritance rules
+-- (derived from the biblatex package manual v3.20, appendix A)
+-- FIXME: This is not complete
+local crossrefmap = {
+   book = {
+      inbook = {
+         author = "author", -- inbook inherits author from book author
+         bookauthor = "author", -- inbook inherits bookauthor from book author
+         indexsorttitle = false, -- inbook skips (=does not inherit) indexsorttitle from book
+         indextitle = false,
+         shorttitle = false,
+         sorttitle = false,
+         subtitle = "booksubtitle",
+         title = "booktitle",
+         titleaddon = "booktitleaddon",
+      },
+   },
+   periodical = {
+      article = {
+         indexsorttitle = false,
+         indextitle = false,
+         shorttitle = false,
+         sorttitle = false,
+         subtitle = "journalsubtitle",
+         title = "journaltitle",
+         titleaddon = "journaltitleaddon",
+      },
+   },
+   proceedings = {
+      inproceedings = {
+         indexsorttitle = false,
+         indextitle = false,
+         shorttitle = false,
+         sorttitle = false,
+         subtitle = "booksubtitle",
+         title = "booktitle",
+         titleaddon = "booktitleaddon",
+      },
+   },
+}
+
+-- biblatex field aliases
+-- From biblatex package manual v3.20, section 2.2.5
+local fieldmap = {
+   address = "location",
+   annote = "annotation",
+   archiveprefix = "eprinttype",
+   key = "sortkey",
+   pdf = "file",
+   journal = "journaltitle",
+   primaryclass = "eprintclass",
+   school = "institution",
+}
+
+return {
+   crossrefmap = crossrefmap,
+   fieldmap = fieldmap,
+}

packages/bibtex/init.lua

@@ -47,7 +47,30 @@ end)
 -- stylua: ignore end
 ---@diagnostic enable: undefined-global, unused-local, lowercase-global
 
-local parseBibtex = function (fn)
+local bibcompat = require("packages.bibtex.bibmaps")
+local crossrefmap, fieldmap = bibcompat.crossrefmap, bibcompat.fieldmap
+
+local function consolidateEntry (entry, label)
+   local consolidated = {}
+   for field, value in pairs(entry.attributes) do
+      consolidated[field] = value
+      local alias = fieldmap[field]
+      if alias then
+         if entry.attributes[alias] then
+            SU.warn("Duplicate field '" .. field .. "' and alias '" .. alias .. "' in entry '" .. label .. "'")
+         else
+            consolidated[alias] = value
+         end
+      end
+   end
+   entry.attributes = consolidated
+   return entry
+end
+
+--- Parse a BibTeX file and populate a bibliography table.
+-- @tparam string fn Filename
+-- @tparam table biblio Table of entries
+local function parseBibtex (fn, biblio)
    fn = SILE.resolveFile(fn) or SU.error("Unable to resolve Bibtex file " .. fn)
    local fh, e = io.open(fn)
    if e then
@@ -58,14 +81,45 @@ local parseBibtex = function (fn)
    if not t or not t[1] or t.id ~= "document" then
       SU.error("Error parsing bibtex")
    end
-   local entries = {}
    for i = 1, #t do
       if t[i].id == "entry" then
          local ent = t[i][1]
-         entries[ent.label] = { type = ent.type, attributes = ent[1] }
+         local entry = { type = ent.type, attributes = ent[1] }
+         if biblio[ent.label] then
+            SU.warn("Duplicate entry key '" .. ent.label .. "', picking the last one")
+         end
+         biblio[ent.label] = consolidateEntry(entry, ent.label)
+      end
+   end
+end
+
+--- Copy fields from the parent entry to the child entry.
+-- BibLaTeX/Biber have a complex inheritance system for fields.
+-- This implementation is more naive, but should be sufficient for reasonable
+-- use cases.
+-- @tparam table parent Parent entry
+-- @tparam table entry Child entry
+local function fieldsInherit (parent, entry)
+   local map = crossrefmap[parent.type] and crossrefmap[parent.type][entry.type]
+   if not map then
+      -- @xdata and any other unknown types: inherit all missing fields
+      for field, value in pairs(parent.attributes) do
+         if not entry.attributes[field] then
+            entry.attributes[field] = value
+         end
+      end
+      return -- done
+   end
+   for field, value in pairs(parent.attributes) do
+      if map[field] == nil and not entry.attributes[field] then
+         entry.attributes[field] = value
+      end
+      for childfield, parentfield in pairs(map) do
+         if parentfield and not entry.attributes[parentfield] then
+            entry.attributes[parentfield] = parent.attributes[childfield]
+         end
       end
    end
-   return entries
 end
 
 --- Resolve the 'crossref' and 'xdata' fields on a bibliography entry.
@@ -104,11 +158,7 @@ local function crossrefAndXDataResolve (bib, entry)
       local parent = bib[ref]
       if parent then
          crossrefAndXDataResolve(bib, parent)
-         for k, v in pairs(parent.attributes) do
-            if not entry.attributes[k] then
-               entry.attributes[k] = v
-            end
-         end
+         fieldsInherit(parent, entry)
       else
          SU.warn("Unknown crossref " .. ref .. " in bibliography entry " .. entry.label)
       end
@@ -133,7 +183,7 @@ end
 function package:registerCommands ()
    self:registerCommand("loadbibliography", function (options, _)
       local file = SU.required(options, "file", "loadbibliography")
-      SILE.scratch.bibtex.bib = parseBibtex(file) -- Later we'll do multiple bibliogs, but not now
+      parseBibtex(file, SILE.scratch.bibtex.bib)
    end)
 
    self:registerCommand("bibstyle", function (_, _)

packages/bibtex/styles/chicago.lua

@@ -20,7 +20,7 @@ local ChicagoStyles = pl.tablex.merge(Bibliography.Style, {
             ". ",
             quotes(title, "."),
             " ",
-            italic(journal),
+            italic(journaltitle),
             optional(" ", volume),
             optional(" no. ", number),
             optional(" ", parens(optional(month, " "), year)),
@@ -34,7 +34,7 @@ local ChicagoStyles = pl.tablex.merge(Bibliography.Style, {
          ". ",
          quotes(title, "."),
          " ",
-         italic(journal),
+         italic(journaltitle),
          optional(", ", month),
          optional(", ", year),
          optional(": ", pageRange),
@@ -59,7 +59,7 @@ local ChicagoStyles = pl.tablex.merge(Bibliography.Style, {
             " ",
             optional("In ", italic(booktitle), ". "),
             optional(transEditor, ". "),
-            optional(address, ": "),
+            optional(location, ": "),
             optional(pub, year and ", " or ". "),
             optional(year, ". "),
             optional(number, ". "),
@@ -70,7 +70,7 @@ local ChicagoStyles = pl.tablex.merge(Bibliography.Style, {
          italic(title),
          ". ",
          optional(transEditor, ". "),
-         optional(address, ": "),
+         optional(location, ": "),
          optional(pub, year and ", " or ". "),
          optional(year, ". "),
          optional(number, ". "),
@@ -85,7 +85,7 @@ local ChicagoStyles = pl.tablex.merge(Bibliography.Style, {
          " ",
          optional(transEditor, ". "),
          optional(bibtype, ". "), -- "type" from BibTeX entry
-         optional(address, ": "),
+         optional(location, ": "),
          optional(pub, ", "),
          optional(year, ".")
    end,