improve Makefile and pandoc configuration

Makefile

@@ -3,8 +3,9 @@ BASE_PATH =
 
 SITE = _site
 
-PAGES = $(filter-out index, $(basename $(notdir $(wildcard md/*.md))))
-CONTENT = $(addprefix $(SITE)/, etc css img index.html $(addsuffix /index.html, $(PAGES)))
+FILES = $(shell find md -type f -name \*.md)
+PAGES = $(patsubst %.md, %/index.html, $(patsubst %/index.md, %/index.html, $(FILES)))
+CONTENT = $(addprefix $(SITE)/, css etc img) $(patsubst md/%, $(SITE)/%, $(PAGES))
 
 PANDOC = pandoc -d defaults.yml -M base_url=$(BASE_URL) -M base_path=$(BASE_PATH)
 
@@ -15,14 +16,14 @@ RM = rm -rf
 all: $(CONTENT)
 
 $(SITE)/%: %
-	@echo ">> Copying $^"
+	@echo ">> Copying $<"
 	@$(MKDIR) $(@D)
-	@$(CP) $^ $@
+	@$(CP) $< $(@D)
 
 $(SITE)/%.html $(SITE)/%/index.html: md/%.md
-	@echo ">> Converting $^"
+	@echo ">> Converting $<"
 	@$(MKDIR) $(@D)
-	@$(PANDOC) -M page=$* -o $@ $^
+	@$(PANDOC) -M page=$* -o $@ $<
 
 serve:
 	@python3 -m http.server --bind 127.0.0.1 --directory $(SITE)

defaults.yml

@@ -1,7 +1,7 @@
 standalone: true
 template: page.html
 
-reader: markdown-implicit_figures
+reader: commonmark+gfm_auto_identifiers+pipe_tables
 writer: html
 
 highlight-style: null

filters.lua

@@ -11,24 +11,24 @@ end
 
 function change_meta(m)
   meta = m
-  if m.page == "index" then
-    m.canonical = stringify(m.base_url) .. "/"
-  else
-    m.canonical = stringify(m.base_url) .. "/" .. m.page .. "/"
+  p = m.page:gsub("/?index$", "")
+  if p ~= "" then
+    p = p .. "/"
   end
+  m.canonical = stringify(m.base_url) .. "/" .. p
   m.title = title or m.site_title
   return m
 end
 
 function expand(s)
-  v = meta[s:sub(2, -2)]
+  v = meta[s]
   if v then
     return stringify(v)
   end
 end
 
 function change_link_target(l)
-  l.target = l.target:gsub("(%b$$)", expand)
+  l.target = l.target:gsub("%$(.-)%$", expand)
   if l.target:sub(1, 1) == "/" then
     l.target = meta.base_path .. l.target
   end