support writing moodle tests in markdown

5 files changed, 164 insertions, 1 deletions

diff --git a/.gitignore b/.gitignore
index 939f3c74..8722f7a3 100644
--- a/.gitignore
+++ b/.gitignore
@@ -15,6 +15,8 @@ test_loesung.pdf
 sequence.pdf
 *print.pdf
 *_printout.pdf
+moodle-quiz.xml
+!pandoc/templates/moodle-quiz.xml
 .build/
 .owncloudsync.log*
 .sync_journal.db*
diff --git a/common.mk b/common.mk
index f4ad4ebe..01f08546 100644
--- a/common.mk
+++ b/common.mk
@@ -70,6 +70,10 @@ schedule.pdf: schedule.md $(MAKEFILE_LIST)
 	@echo "building $@"
 	$(VERBOSE)$(PANDOC) --pdf-engine-opt=--fmt=$(LATEX_FMT_BASE)/schedule.fmt -f markdown $< -o $@
 
+moodle-quiz.xml: moodle-quiz.md $(wildcard img/*) $(MAKEFILE_LIST)
+	@echo "building $@"
+	$(VERBOSE)$(PANDOC) --template=$(PANDOC_TEMPLATE_DIR)/moodle-quiz.xml -t $(PANDOC_FILTER_DIR)/moodle-quiz.lua --embed-resources $< -o $@
+
 %.pdf: %.md $(MAKEFILE_LIST)
 	@echo "building $@"
 	$(VERBOSE)$(PANDOC) -f markdown $< -o $@
diff --git a/pandoc/filters/moodle-quiz.lua b/pandoc/filters/moodle-quiz.lua
new file mode 100644
index 00000000..ab26f93c
--- /dev/null
+++ b/pandoc/filters/moodle-quiz.lua
@@ -0,0 +1,140 @@
+--- moodle-test.lua – filter to convert markdown questions into Moodle XML
+---
+--- Copyright: © 2026 Florian Fischer
+--- License:   GPL-3.0-or-later
+
+-- Collected questions
+local questions = {}
+local cur_question = nil
+
+local concat = function(inlines)
+	local s = pandoc.write(pandoc.Pandoc(pandoc.Plain(inlines)), 'plain', {wrap_text='wrap-none'})
+	if s:sub(-1) == '\n' then
+		s = s:sub(1, -2)
+	end
+	return s
+end
+
+local function detect_question_type(question)
+	local ret = ""
+	if question.header.classes:includes("shortanswer") then
+		ret = "shortanswer"
+	elseif question.header.classes:includes("multichoice") then
+		ret = "multichoice"
+	else
+		pandoc.warn("No question type found")
+	end
+	return ret
+end
+
+local function write_shortanwser_answers(question)
+	local ret = ""
+	local a = function(s) ret = ret .. s end
+
+	for _, answer in ipairs(question.answers) do
+		a('  <answer fraction="100" format="html">\n')
+		a('    <text><![CDATA[');
+		a(pandoc.write(pandoc.Pandoc(answer), "html"))
+		a(']]></text>\n')
+
+		if answer.feedback then
+			a('    <feedback format="html"><text><![CDATA[')
+			a(pandoc.write(pandoc.Pandoc(answer.feedback), "html"))
+			a(']]></text></feedback>\n')
+		end
+		a('  </answer>\n')
+	end
+	return ret
+end
+
+local write_answers_for = {
+	shortanswer = write_shortanwser_answers,
+}
+
+local function write_questions()
+	local res = ""
+	local a = function(s) res = res .. s end
+
+	for _, question in ipairs(questions) do
+		if not question then
+			pandoc.log.warn("nil question")
+		end
+		local question_type = detect_question_type(question)
+		-- Question type
+		a('<question type="' ..  question_type .. '">\n')
+
+		-- Question name
+		a('  <name><text>');
+		a(concat(question.name))
+		a('</text></name>\n')
+
+		-- Question text
+		a('  <questiontext format="html">\n    <text><![CDATA[')
+		for _, part in ipairs(question.text) do
+			a(pandoc.write(pandoc.Pandoc(part), "html"))
+		end
+		a(']]></text>\n  </questiontext>\n')
+		a('  <generalfeedback format="html"><text></text></generalfeedback>\n')
+		a('  <defaultgrade>1.0000000</defaultgrade>\n')
+		a('  <penalty>0.3333333</penalty>\n')
+		a('  <hidden>0</hidden>\n')
+		a('  <idnumber></idnumber>\n')
+		a('  <usecase>0</usecase>\n')
+
+		local answer_fn = write_answers_for[question_type]
+		a(answer_fn(question))
+		a('</question>\n')
+	end
+
+	return res
+end
+
+local function Header(h)
+	cur_question = { header=h, text={}}
+	table.insert(questions, cur_question)
+
+	cur_question.name = h.content
+end
+
+local function Image(i)
+	local datauri = pandoc.mediabag.make_data_uri(pandoc.mediabag.fetch(i.src))
+	return pandoc.Image(i.caption, datauri)
+end
+
+local function Div(d)
+	-- append question content
+	table.insert(cur_question.text, pandoc.walk_block(d, {Image=Image})) -- embed all images
+end
+
+local function BulletList(l)
+	cur_question.answers = l.content
+end
+
+local filter = {
+	-- Traverse the AST depth-first to reach the content of a question after
+	-- reaching its header
+	traverse = 'topdown',
+	Header = Header, -- Detect questions
+	Div = Div, -- Collect question content
+	BulletList = BulletList, -- Collect question answers
+}
+
+Writer = function(doc, opts)
+	local ctx = pandoc.template.meta_to_context(doc.meta, concat, concat)
+
+	-- collect questions
+	doc:walk(filter)
+	local body = write_questions()
+
+	ctx['body'] = body
+	for k, v in pairs(opts.variables) do
+		ctx[k] = v
+	end
+
+	if not opts.template then
+		pandoc.log.warn("No quiz template specified")
+		os.exit(1)
+	end
+	local complete = pandoc.template.apply(opts.template, ctx)
+	return complete:render()
+end
diff --git a/pandoc/templates/moodle-quiz.xml b/pandoc/templates/moodle-quiz.xml
new file mode 100644
index 00000000..761c8669
--- /dev/null
+++ b/pandoc/templates/moodle-quiz.xml
@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<quiz>
+<!-- question: 0  -->
+  <question type="category">
+    <category>
+      <text>$$module$$/top/Standard für ${title}</text>
+    </category>
+    <info format="moodle_auto_format">
+      <text>Standardkategorie für Fragen, die im Kontext '${title}' freigegeben sind.</text>
+    </info>
+    <idnumber></idnumber>
+  </question>
+
+${body}
+</quiz>
diff --git a/scripts/lesson-make b/scripts/lesson-make
index d5639b7a..3c6a4890 100755
--- a/scripts/lesson-make
+++ b/scripts/lesson-make
@@ -22,6 +22,9 @@ if [[ -z "${targets[*]}" ]]; then
 		slides*.md)
 			new_targets+=("${source_name/.md/.pdf}" "${source_name/.md/.pptx}")
 			;;
+		moodle-quiz.md)
+			new_targets+=("${source_name/.md/.xml}")
+			;;
 		*)
 			mapfile -t new_targets < <(echo "${source}" | sed -e 's/\.tex$/.pdf/g' -e 's/\.md$/.pdf/g')
 			;;
@@ -43,4 +46,3 @@ if [[ -z "${targets[*]}" ]]; then
 fi
 
 exec make -f "${MAKEFILE}" "${targets[@]}"
-