diff --git a/src/lua/util.lua b/src/lua/util.lua
index 58224da..e07c5a1 100644
--- a/src/lua/util.lua
+++ b/src/lua/util.lua
@@ -48,14 +48,15 @@ local url_characters_legacy =
 	url_characters ..
 	[[$-+!*'(),]]
 
-local url_characters_rev = {}
-for i = 1,string.len(url_characters) do
-	url_characters_rev[string.sub(url_characters,i,i)] = i
-end
-local url_characters_rev_legacy = {}
-for i = 1,string.len(url_characters_legacy) do
-	url_characters_rev_legacy[string.sub(url_characters_legacy,i,i)] = i
+local function str2set(str)
+	local tbl = {}
+	for i = 1, #str do
+		tbl[string.sub(str,i,i)] = i
+	end
+	return tbl
 end
+local url_characters_rev = str2set(url_characters)
+local url_characters_rev_legacy = str2set(url_characters_legacy)
 
 --[[ md
 @name lua/util/encode_id
@@ -64,10 +65,9 @@ according to the {{doc/url_spec}
 ]]
 function util.encode_id(number)
         local result = {}
-        local charlen = string.len(url_characters)
 	repeat
-                local pos = (number % charlen) + 1
-		number = math.floor(number / charlen)
+                local pos = (number % #url_characters) + 1
+		number = math.floor(number / #url_characters)
                 table.insert(result,string.sub(url_characters,pos,pos))
 	until number == 0
         return table.concat(result)
@@ -81,10 +81,9 @@ function util.encode_id(number)
 		return new_encode(number)
 	else
 		local result = {}
-		local charlen = string.len(url_characters_legacy)
 		repeat
-			local pos = (number % charlen) + 1
-			number = math.floor(number / charlen)
+			local pos = (number % #url_characters_legacy) + 1
+			number = math.floor(number / #url_characters_legacy)
 			table.insert(result,string.sub(url_characters_legacy,pos,pos))
 		until number == 0
 		return table.concat(result)
@@ -97,11 +96,10 @@ Given a short HTML-safe url path, convert it to a storyid
 function util.decode_id(s)
 	local res, id = pcall(function()
 		local n = 0
-		local charlen = string.len(url_characters)
 		for i = 1,string.len(s) do
 			local char = string.sub(s,i,i)
 			local pos = url_characters_rev[char] - 1
-			n = n + (pos*math.pow(charlen,i-1))
+			n = n + (pos*math.pow(#url_characters,i-1))
 		end
 		return n
 	end)
@@ -119,11 +117,10 @@ local new_decode = util.decode_id
 function util.decode_id(s)
 	local res, id = pcall(function()
 		local n = 0
-		local charlen = string.len(url_characters_legacy)
 		for i = 1,string.len(s) do
 			local char = string.sub(s,i,i)
 			local pos = url_characters_rev_legacy[char] - 1
-			n = n + (pos * math.pow(charlen,i-1))
+			n = n + (pos * math.pow(#url_characters_legacy,i-1))
 		end
 		return n
 	end)
@@ -172,10 +169,8 @@ function util.parse_tags(str)
 	local tags = {}
 	for tag in string.gmatch(str,"([^;]+)") do
 		assert(tag, "Found a nil or false tag in:" .. str)
-		local tag_trimmed = string.match(tag,"%s*(.*)%s*")
-		local tag_lower = string.lower(tag_trimmed)
-		local tag_capitalized = string.gsub(tag_lower,"^.",string.upper)
-		assert(tag_capitalized, "After processing tag:" .. tag .. " it was falsey.")
+		local tag_fmt = tag:match("%s*(.*)%s*"):lower():gsub("^.",string.upper)
+		assert(tag_fmt, "After processing tag:" .. tag .. " it was falsey.")
 		if string.len(tag_capitalized) > 0 then
 			table.insert(tags, tag_capitalized)
 		end
@@ -194,9 +189,7 @@ comment :: table {
 }
 ]]
 function util.get_comments(sid)
-	stmnt_comments:bind_names{
-		id = sid
-	}
+	stmnt_comments:bind_names{id = sid}
 	local comments = {}
 	for com_author, com_isanon, com_text in db.sql_rows(stmnt_comments) do
 		table.insert(comments,{