Refactor logging

- Add warning log level
- Change debug_log_level setting to enumeration string
- Map Irrlicht log events to MT log events
- Encapsulate log_* functions and global variables into a class, Logger
- Unify dstream with standard logging mechanism
- Unify core.debug() with standard core.log() script API

builtin/common/strict.lua

@@ -9,11 +9,6 @@ function core.global_exists(name)
 end
 
 
-local function warn(message)
-	print(os.date("%H:%M:%S: WARNING: ")..message)
-end
-
-
 local meta = {}
 local declared = {}
 -- Key is source file, line, and variable name; seperated by NULs
@@ -27,7 +22,7 @@ function meta:__newindex(name, value)
 				info.currentline, name)
 		if not warned[warn_key] and info.what ~= "main" and
 				info.what ~= "C" then
-			warn(("Assignment to undeclared "..
+			core.log("warning", ("Assignment to undeclared "..
 					"global %q inside a function at %s.")
 				:format(name, desc))
 			warned[warn_key] = true
@@ -35,9 +30,8 @@ function meta:__newindex(name, value)
 		declared[name] = true
 	end
 	-- Ignore mod namespaces
-	if WARN_INIT and (not core.get_current_modname or
-			name ~= core.get_current_modname()) then
-		warn(("Global variable %q created at %s.")
+	if WARN_INIT and name ~= core.get_current_modname() then
+		core.log("warning", ("Global variable %q created at %s.")
 			:format(name, desc))
 	end
 	rawset(self, name, value)
@@ -48,7 +42,7 @@ function meta:__index(name)
 	local info = debug.getinfo(2, "Sl")
 	local warn_key = ("%s\0%d\0%s"):format(info.source, info.currentline, name)
 	if not declared[name] and not warned[warn_key] and info.what ~= "C" then
-		warn(("Undeclared global variable %q accessed at %s:%s")
+		core.log("warning", ("Undeclared global variable %q accessed at %s:%s")
 				:format(name, info.short_src, info.currentline))
 		warned[warn_key] = true
 	end

builtin/fstk/ui.lua

@@ -127,11 +127,13 @@ function ui.update()
 		end
 
 		if (active_toplevel_ui_elements > 1) then
-			print("WARNING: ui manager detected more then one active ui element, self most likely isn't intended")
+			core.log("warning", "more than one active ui "..
+				"element, self most likely isn't intended")
 		end
 
 		if (active_toplevel_ui_elements == 0) then
-			print("WARNING: not a single toplevel ui element active switching to default")
+			core.log("warning", "no toplevel ui element "..
+					"active; switching to default")
 			ui.childlist[ui.default]:show()
 			formspec = ui.childlist[ui.default]:get_formspec()
 		end

builtin/game/deprecated.lua

@@ -4,8 +4,7 @@
 -- Default material types
 --
 local function digprop_err()
-	core.log("info", debug.traceback())
-	core.log("info", "WARNING: The core.digprop_* functions are obsolete and need to be replaced by item groups.")
+	core.log("deprecated", "The core.digprop_* functions are obsolete and need to be replaced by item groups.")
 end
 
 core.digprop_constanttime = digprop_err
@@ -16,12 +15,12 @@ core.digprop_woodlike = digprop_err
 core.digprop_leaveslike = digprop_err
 core.digprop_glasslike = digprop_err
 
-core.node_metadata_inventory_move_allow_all = function()
-	core.log("info", "WARNING: core.node_metadata_inventory_move_allow_all is obsolete and does nothing.")
+function core.node_metadata_inventory_move_allow_all()
+	core.log("deprecated", "core.node_metadata_inventory_move_allow_all is obsolete and does nothing.")
 end
 
-core.add_to_creative_inventory = function(itemstring)
-	core.log('info', "WARNING: core.add_to_creative_inventory: This function is deprecated and does nothing.")
+function core.add_to_creative_inventory(itemstring)
+	core.log("deprecated", "core.add_to_creative_inventory: This function is deprecated and does nothing.")
 end
 
 --
@@ -32,7 +31,7 @@ local envref_deprecation_message_printed = false
 setmetatable(core.env, {
 	__index = function(table, key)
 		if not envref_deprecation_message_printed then
-			core.log("info", "WARNING: core.env:[...] is deprecated and should be replaced with core.[...]")
+			core.log("deprecated", "core.env:[...] is deprecated and should be replaced with core.[...]")
 			envref_deprecation_message_printed = true
 		end
 		local func = core[key]

builtin/game/register.lua

@@ -221,7 +221,7 @@ function core.register_alias(name, convert_to)
 		error("Unable to register alias: Name is forbidden: " .. name)
 	end
 	if core.registered_items[name] ~= nil then
-		core.log("WARNING: Not registering alias, item with same name" ..
+		core.log("warning", "Not registering alias, item with same name" ..
 			" is already defined: " .. name .. " -> " .. convert_to)
 	else
 		--core.log("Registering alias: " .. name .. " -> " .. convert_to)

builtin/init.lua

@@ -6,7 +6,7 @@
 --
 
 -- Initialize some very basic things
-print = core.debug
+function core.debug(...) core.log(table.concat({...}, "\t")) end
 math.randomseed(os.time())
 os.setlocale("C", "numeric")
 minetest = core