From 58042b5135ddf74bf5945c46eafd3828739e045c Mon Sep 17 00:00:00 2001
From: Jonas Smedegaard <dr@jones.dk>
Date: Mon, 24 Feb 2025 15:00:10 +0100
Subject: initial draft
---
.../abstract-section/abstract-section.lua | 85 ++++++++++++++++++++++
1 file changed, 85 insertions(+)
create mode 100644 _extensions/pandoc-ext/abstract-section/abstract-section.lua
(limited to '_extensions/pandoc-ext/abstract-section/abstract-section.lua')
diff --git a/_extensions/pandoc-ext/abstract-section/abstract-section.lua b/_extensions/pandoc-ext/abstract-section/abstract-section.lua
new file mode 100644
index 0000000..4badeb4
--- /dev/null
+++ b/_extensions/pandoc-ext/abstract-section/abstract-section.lua
@@ -0,0 +1,85 @@
+--[[
+abstract-section – move an "abstract" section into document metadata
+
+Copyright: © 2017–2023 Albert Krewinkel
+License: MIT – see LICENSE file for details
+]]
+local stringify = (require 'pandoc.utils').stringify
+local section_identifiers = {
+ abstract = true,
+}
+local collected = {}
+--- The level of the highest heading that was seen so far. Abstracts
+--- must be at or above this level to prevent nested sections from being
+--- treated as metadata. Only top-level sections should become metadata.
+local toplevel = 6
+
+--- Extract abstract from a list of blocks.
+local function abstract_from_blocklist (blocks)
+ local body_blocks = {}
+ local looking_at_section = false
+
+ for _, block in ipairs(blocks) do
+ if block.t == 'Header' and block.level <= toplevel then
+ toplevel = block.level
+ if section_identifiers[block.identifier] then
+ looking_at_section = block.identifier
+ collected[looking_at_section] = {}
+ else
+ looking_at_section = false
+ body_blocks[#body_blocks + 1] = block
+ end
+ elseif looking_at_section then
+ if block.t == 'HorizontalRule' then
+ looking_at_section = false
+ else
+ local collect = collected[looking_at_section]
+ collect[#collect + 1] = block
+ end
+ else
+ body_blocks[#body_blocks + 1] = block
+ end
+ end
+
+ return body_blocks
+end
+
+Pandoc = function (doc)
+ local meta = doc.meta
+
+ -- configure
+ section_identifiers_list =
+ (doc.meta['abstract-section'] or {})['section-identifiers']
+ if section_identifiers_list and #section_identifiers_list > 0 then
+ section_identifiers = {}
+ for i, ident in ipairs(section_identifiers_list) do
+ section_identifiers[stringify(ident)] = true
+ end
+ end
+ -- unset config in meta
+ doc.meta['abstract-section'] = nil
+
+ local blocks = {}
+ if PANDOC_VERSION >= {2,17} then
+ -- Walk all block lists by default
+ blocks = doc.blocks:walk{Blocks = abstract_from_blocklist}
+ elseif PANDOC_VERSION >= {2,9,2} then
+ -- Do the same with pandoc versions that don't have walk methods but the
+ -- `walk_block` function.
+ blocks = pandoc.utils.walk_block(
+ pandoc.Div(doc.blocks),
+ {Blocks = abstract_from_blocklist}
+ ).content
+ else
+ -- otherwise, just check the top-level block-list
+ blocks = abstract_from_blocklist(doc.blocks)
+ end
+ for metakey in pairs(section_identifiers) do
+ metakey = stringify(metakey)
+ local abstract = collected[metakey]
+ if not meta[metakey] and abstract and #abstract > 0 then
+ meta[metakey] = pandoc.MetaBlocks(abstract)
+ end
+ end
+ return pandoc.Pandoc(blocks, meta)
+end
--
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