add extensions

_extensions/pandoc-ext/scholarly-metadata/_extension.yaml

@@ -0,0 +1,6 @@
+name: scholarly-metadata
+author: Albert Krewinkel
+version: 1.0.0
+contributes:
+  filters:
+    - scholarly-metadata.lua

_extensions/pandoc-ext/scholarly-metadata/scholarly-metadata.lua

@@ -0,0 +1,197 @@
+--[[
+ScholarlyMeta – normalize author/affiliation meta variables
+
+Copyright (c) 2017-2021 Albert Krewinkel, Robert Winkler
+
+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 List = require("pandoc.List")
+
+--- Returns the type of a metadata value.
+--
+-- @param v a metadata value
+-- @treturn string one of `Blocks`, `Inlines`, `List`, `Map`, `string`, `boolean`
+local function metatype(v)
+	if PANDOC_VERSION <= "2.16.2" then
+		local metatag = type(v) == "table" and v.t and v.t:gsub("^Meta", "")
+		return metatag and metatag ~= "Map" and metatag or type(v)
+	end
+	return pandoc.utils.type(v)
+end
+
+local type = pandoc.utils.type or metatype
+
+-- Split a string at commas.
+local function comma_separated_values(str)
+	local acc = List:new({})
+	for substr in str:gmatch("([^,]*)") do
+		acc[#acc + 1] = substr:gsub("^%s*", ""):gsub("%s*$", "") -- trim
+	end
+	return acc
+end
+
+--- Ensure the return value is a list.
+local function ensure_list(val)
+	if type(val) == "List" then
+		return val
+	elseif type(val) == "Inlines" then
+		-- check if this is really a comma-separated list
+		local csv = comma_separated_values(pandoc.utils.stringify(val))
+		if #csv >= 2 then
+			return csv
+		end
+		return List:new({ val })
+	elseif type(val) == "table" and #val > 0 then
+		return List:new(val)
+	else
+		-- Anything else, use as a singleton (or empty list if val == nil).
+		return List:new({ val })
+	end
+end
+
+--- Returns a function which checks whether an object has the given ID.
+local function has_id(id)
+	return function(x)
+		return x.id == id
+	end
+end
+
+--- Copy all key-value pairs of the first table into the second iff there is no
+-- such key yet in the second table.
+-- @returns the second argument
+function add_missing_entries(a, b)
+	for k, v in pairs(a) do
+		b[k] = b[k] or v
+	end
+	return b
+end
+
+--- Create an object with a name. The name is either taken directly from the
+-- `name` field, or from the *only* field name (i.e., key) if the object is a
+-- dictionary with just one entry. If neither exists, the name is left unset
+-- (`nil`).
+function to_named_object(obj)
+	local named = {}
+	if type(obj) == "Inlines" then
+		-- Treat inlines as the name
+		named.name = obj
+		named.id = pandoc.utils.stringify(obj)
+	elseif type(obj) ~= "table" then
+		-- if the object isn't a table, just use its value as a name.
+		named.name = pandoc.MetaInlines({ pandoc.Str(tostring(obj)) })
+		named.id = tostring(obj)
+	elseif obj.name ~= nil then
+		-- object has name attribute → just create a copy of the object
+		add_missing_entries(obj, named)
+		named.id = pandoc.utils.stringify(named.id or named.name)
+	elseif next(obj) and next(obj, next(obj)) == nil then
+		-- Single-entry table. The entry's key is taken as the name, the value
+		-- contains the attributes.
+		key, attribs = next(obj)
+		if type(attribs) == "string" or type(attribs) == "Inlines" then
+			named.name = attribs
+		else
+			add_missing_entries(attribs, named)
+			named.name = named.name or pandoc.MetaInlines({ pandoc.Str(tostring(key)) })
+		end
+		named.id = named.id and pandoc.utils.stringify(named.id) or key
+	else
+		-- this is not a named object adhering to the usual conventions.
+		error("not a named object: " .. tostring(obj))
+	end
+	return named
+end
+
+--- Resolve affiliations placeholders to full named objects
+local function resolve_affiliations(affiliations, known_affiliations)
+	local unresolved_affiliations
+	if affiliations == nil then
+		unresolved_affiliations = {}
+	elseif type(affiliations) == "string" or type(affiliations) == "number" then
+		unresolved_affiliations = { affiliations }
+	else
+		unresolved_affiliations = affiliations
+	end
+
+	local result = List:new({})
+	for i, inst in ipairs(unresolved_affiliations) do
+		result[i] = known_affiliations[tonumber(inst)]
+			or known_affiliations:find_if(has_id(pandoc.utils.stringify(inst)))
+			or to_named_object(inst)
+	end
+	return result
+end
+
+--- Insert a named object into a list; if an object of the same name exists
+-- already, add all properties only present in the new object to the existing
+-- item.
+function merge_on_id(list, namedObj)
+	local elem, idx = list:find_if(has_id(namedObj.id))
+	local res = elem and add_missing_entries(namedObj, elem) or namedObj
+	local obj_idx = idx or (#list + 1)
+	-- return res, obj_idx
+	list[obj_idx] = res
+	return res, #list
+end
+
+--- Flatten a list of lists.
+local function flatten(lists)
+	local result = List:new({})
+	for _, lst in ipairs(lists) do
+		result:extend(lst)
+	end
+	return result
+end
+
+--- Canonicalize authors and affiliations
+local function canonicalize(raw_author, raw_affiliations)
+	local affiliations = ensure_list(raw_affiliations):map(to_named_object)
+	local authors = ensure_list(raw_author):map(to_named_object)
+
+	for _, author in ipairs(authors) do
+		author.affiliations = resolve_affiliations(ensure_list(author.affiliations), affiliations)
+	end
+
+	-- Merge affiliations defined in author objects with those defined in the
+	-- top-level list.
+	local author_insts = flatten(authors:map(function(x)
+		return x.affiliations
+	end))
+	for _, inst in ipairs(author_insts) do
+		merge_on_id(affiliations, inst)
+	end
+
+	-- Add list indices to affiliations for numbering and reference purposes
+	for idx, inst in ipairs(affiliations) do
+		inst.index = pandoc.MetaInlines({ pandoc.Str(tostring(idx)) })
+	end
+
+	-- replace affiliations with their indices
+	local to_index = function(inst)
+		return tostring(select(2, affiliations:find_if(has_id(inst.id))))
+	end
+	for _, author in ipairs(authors) do
+		author.affiliations = pandoc.MetaList(author.affiliations:map(to_index))
+	end
+
+	return authors, affiliations
+end
+
+return {
+	{
+		Meta = function(meta)
+			meta.author, meta.affiliations = canonicalize(meta.author, meta.affiliations)
+			return meta
+		end,
+	},
+}