Lua vardump with cycle detection

vardump.lua

_G['vardump'] = function(var, longform, prefix, refs)
	prefix = prefix or ''
	refs = refs or {}
	
	if type(var) == 'table' then
		local cyclic = not not refs[var]
		refs[var] = true
		print(prefix .. tostring(var) .. (cyclic and ' (cyclic)' or ''))
		if not cyclic then
			prefix = prefix .. ' '
			for k,v in pairs(var) do
				print(prefix .. tostring(k) .. ': ' .. '(' .. type(v) .. ')')
				vardump(v, longform, prefix .. '| ', refs)
			end
			refs[var] = not longform			
		end
	else
		local str = tostring(var)
		str = string.gsub(str, '[^%a%s%d%p%%%^%$%(%)%[%]%*%+%-%?_~|{}\\]', '?')
		print(prefix .. (type(var) == 'string' and '"' .. str .. '"' or str))
	end
end