1 files changed, 57 insertions, 16 deletions

diff --git a/catalogue.lua b/catalogue.lua
index 0eca2f3..5444d17 100644
--- a/catalogue.lua
+++ b/catalogue.lua
@@ -29,6 +29,24 @@ function mt:get(id)
 	return self.data[id]
 end
 
+function mt:_ensure_catchall(section_id)
+	local id = section_id .. ':category:catchall'
+	local entry = self.data[id]
+	if entry then
+		return entry
+	end
+
+	return self:add({
+		section = section_id,
+		type = 'group',
+		group_type = 'category',
+		id = id,
+		parent_id = section_id .. ':category:0',
+		-- non-ascii symbol to sort near end
+		name = '∗CATCHALL∗',
+	})
+end
+
 function mt:add(entry)
 	self.data[entry.id] = entry
 
@@ -37,28 +55,25 @@ function mt:add(entry)
 	end
 
 	if not entry.parent_id then
-		return
+		return entry
 	end
 
+	local parent = self.data[entry.parent_id]
+
 	-- dump any entries referencing nonexistent categories into a single
 	-- catchall category
-	if not self.data[entry.parent_id] then
-		entry.parent_id = entry.section .. ':category:catchall'
-		if not self.data[entry.parent_id] then
-			self:add({
-				section = entry.section,
-				type = 'group',
-				group_type = 'category',
-				id = entry.parent_id,
-				parent_id = entry.section .. ':category:0',
-				-- non-ascii symbol to sort near end
-				name = '∗CATCHALL∗',
-			})
-		end
+	if not parent then
+		parent = self:_ensure_catchall(entry.section)
+		entry.parent_id = parent.id
+	end
+
+	if parent.id == entry.id then
+		entry.parent_id = nil
+	else
+		parent.children[#parent.children+1] = entry
 	end
 
-	local parent_children = self.data[entry.parent_id].children
-	parent_children[#parent_children+1] = entry
+	return entry
 end
 
 function mt:load_xc_section(section)
@@ -111,4 +126,30 @@ function mt:load_xc_section(section)
 	end
 end
 
+function mt:path_to_root(entry)
+	local path = {}
+
+	local curr = entry
+	while curr.parent_id and curr.parent_id ~= 'root' do
+		curr = self:get(curr.parent_id)
+		if not curr then
+			return
+		end
+		path[#path+1] = curr
+	end
+	if curr.parent_id ~= 'root' then
+		return
+	end
+
+	return path
+end
+
+function mt:path_from_root(entry)
+	local path = self:path_to_root(entry)
+	if path then
+		util.reverse(path)
+	end
+	return path
+end
+
 return catalogue