That's it, that's the whole library!

log.lua

@@ -0,0 +1,75 @@
+local stored_messages = {}
+local display_levels = {}
+local enable_logging = true
+local message_limit = math.huge
+
+-- USAGE:
+--   -- set arbitrary log levels to be printed immediately
+--   log{ info = true, warning = true, }
+--   -- send anything (except nil) to a log level
+--   log("bacom", true, "text", 5, function() end, {})
+--   -- print all messages saved at a particular log level
+--   log("error")
+--   -- toggle ALL logging on and off with a boolean
+--   log(false) -- this deletes all stored messages
+--   -- set a maximum number of stored messages per log level
+--   log(50) -- warning: reaching large limits makes logging expensive
+--   -- do anything to the stored messages (this example deletes them all)
+--  log(function(messages) return {} end)
+
+return function(options, ...)
+  local options_type = type(options)
+
+  if (options_type == "string") and enable_logging then
+    if not stored_messages[options] then stored_messages[options] = {} end
+    local message_table = stored_messages[options]
+
+    -- turn log message into text
+    local tab = {...}
+    for i = 1, #tab do
+      tab[i] = tostring(tab[i])
+    end
+    local current_message = table.concat(tab, "\t")
+
+    if #current_message == 0 then
+      -- print all stored_messages of specified level
+      for i = 1, #message_table do
+        print(message_table[i])
+      end
+
+    else
+      -- store message (and print if in display_levels)
+      message_table[#message_table + 1] = current_message
+      if #message_table > message_limit then table.remove(message_table, 1) end
+      if display_levels[options] then print(current_message) end
+    end
+
+  -- set display_levels
+  elseif options_type == "table" then
+    for k,v in pairs(options) do
+      display_levels[k] = v
+    end
+
+  elseif options_type == "number" then
+    message_limit = options
+    for k,v in pairs(stored_messages) do
+      while #v > message_limit do
+        table.remove(v, 1)
+      end
+    end
+
+  -- turn all logging off and delete stored messages; or turn it on
+  elseif options_type == "boolean" then
+    if options then
+      enable_logging = true
+    else
+      enable_logging = false
+      stored_messages = {}
+    end
+
+  -- arbitrary access :D
+  elseif options_type == "function" then
+    local result = options(stored_messages)
+    if type(result) == "table" then stored_messages = result end
+  end
+end