Add "SEE ALSO" section to manual pages where applicable

Makefile

@@ -9,6 +9,7 @@ MAN_PATH = $(MANUAL_ROOT)/man
 MAN_SRCS = $(wildcard $(MAN_PATH)/*/*.md)
 MAN_DSTS = $(MAN_SRCS:%.md=%)
 MAN_TEXS = $(MAN_SRCS:%.md=%.tex)
+MAN_FILTER = $(MANUAL_ROOT)/filter_man.lua
 
 TEX_PATH = $(MANUAL_ROOT)/tex
 MAN_TEX = $(TEX_PATH)/man.tex
@@ -26,11 +27,11 @@ doc-pdf: $(TEX_MAIN_DSTS)
 doc-man: $(MAN_DSTS)
 	find assets/manual/man -regex '.*/[^.]+\.[^.]+$$' | tar -cJf ${MANUAL_ROOT}/man.tar.xz -T -
 
-%:: %.md
-	$(PANDOC) -s -t man -o $@ $<
+%:: %.md ${MAN_FILTER}
+	$(PANDOC) -L ${MAN_FILTER} -s -t man -o $@ $<
 
 $(MAN_TEX): $(MAN_TEXS)
 	find $(MAN_PATH) -name '*.tex' -printf '\\input{../man/%P}\n' | sort > $(MAN_TEX)
 
-%.tex:: %.md ${MANUAL_ROOT}/filter_man_md2tex.lua
-	$(PANDOC) -L ${MANUAL_ROOT}/filter_man_md2tex.lua -t latex -o $@ $<
+%.tex:: %.md ${MAN_FILTER}
+	$(PANDOC) -L ${MAN_FILTER} -t latex -o $@ $<

assets/manual/filter_man.lua

@@ -0,0 +1,73 @@
+local filters = {}
+
+local function add_filter(x)
+	table.insert(filters, x)
+end
+
+local is_latex = FORMAT:match "latex"
+local is_man = FORMAT:match "man"
+
+add_filter {
+	Pandoc = function(elem)
+		local seealso = elem.meta.seealso
+		if not seealso then
+			return
+		end
+		local blocks = elem.blocks
+		blocks:insert(pandoc.Header(1, pandoc.Str("SEE ALSO")))
+		if is_man then
+			for k, v in pairs(seealso) do
+				seealso[k] = v[1].text
+			end
+			blocks:insert(pandoc.Str(table.concat(seealso, ", ")))
+		else
+			local list = {}
+			for _, i in ipairs(seealso) do
+				local page = i[1].text
+				local pgname, pgsection = string.match(page, "^([^%)]+)%(([^%)]+)%)$")
+				local item = pandoc.Str(page)
+				if is_latex and pgname and pgsection then
+					pgname = pgname:gsub("_","\\string_")
+					item = pandoc.RawInline("latex", string.format("\\manref{%s}{%s}", pgname, pgsection))
+				end
+				table.insert(list, item)
+			end
+			blocks:insert(pandoc.BulletList(list))
+		end
+		return elem
+	end
+}
+
+if is_latex then
+	add_filter {
+		Str = function(elem)
+			if elem.tex == "Advtrains" then
+				return pandoc.RawInline("latex", "\\advtrains{}")
+			end
+		end
+	}
+	add_filter {
+		Header = function(elem)
+			local attr = {
+				class = "unnumbered unlisted",
+			}
+			return pandoc.Header(elem.level+1, elem.content, attr)
+		end,
+	}
+	add_filter {
+		Pandoc = function(elem)
+			local outputfn = PANDOC_STATE.output_file or error("No output file specified")
+			local pgname, pgsection = outputfn:match("([^%./\\]+)%.([^%.]+)%.tex$")
+			assert(pgname and pgsection, "Cannot fetch manpage name and section")
+			local blocks = elem.blocks
+			local titlestr = string.format("%s(%s)", pgname, pgsection)
+			local titleid = string.format("man:%s.%s", pgname, pgsection)
+			local titleobj = pandoc.Header(1, pandoc.Code(titlestr))
+			titleobj.identifier = titleid
+			blocks:insert(1, titleobj)
+			return elem
+		end,
+	}
+end
+
+return filters

assets/manual/filter_man_md2tex.lua

@@ -1,31 +0,0 @@
-return {
-	{
-		Str = function(elem)
-			if elem.text == "Advtrains" then
-				return pandoc.RawInline("latex", "\\advtrains{}")
-			end
-		end
-	},
-	{
-		Header = function(elem)
-			local attr = {
-				class = "unnumbered unlisted",
-			}
-			return pandoc.Header(elem.level+1, elem.content, attr)
-		end,
-	},
-	{
-		Pandoc = function(elem)
-			local outputfn = PANDOC_STATE.output_file or error("No output file specified")
-			local pgname, pgsection = outputfn:match("([^%./\\]+)%.([^%.]+)%.tex$")
-			assert(pgname and pgsection, "Cannot fetch manpage name and section")
-			local blocks = elem.blocks
-			local titlestr = string.format("%s(%s)", pgname, pgsection)
-			local titleid = string.format("man:%s.%s", pgname, pgsection)
-			local titleobj = pandoc.Header(1, pandoc.Code(titlestr))
-			titleobj.identifier = titleid
-			blocks:insert(1, titleobj)
-			return elem
-		end,
-	},
-}

assets/manual/man/man7advtrains/rwt.7advtrains.md

@@ -1,4 +1,11 @@
-% RWT(7ADVTRAINS) | Advtrains Developer's Manual
+---
+title: 'RWT(7ADVTRAINS) | Advtrains Developer''s Manual'
+seealso:
+- rwt_add(3advtrains)
+- rwt_copy(3advtrains)
+- rwt_last_rpt(3advtrains)
+- rwt_now(3advtrains)
+---
 
 # NAME
 `rwt` - Advtrains railway time

assets/manual/man/man7advtrains/speed.7advtrains.md

@@ -1,4 +1,9 @@
-% SPEED(7ADVTRAINS) | Advtrains Developer's Manual
+---
+title: 'SPEED(7ADVTRAINS) | Advtrains Developer''s Manual'
+seealso:
+- speed_lessp(3advtrains)
+- speed_set_restriction(3advtrains)
+---
 
 # NAME
 `speed` - Advtrains speed limit library