1 files changed, 29 insertions, 0 deletions
diff --git a/tutorials/tut021_detouring.md b/tutorials/tut021_detouring.md
new file mode 100644
index 0000000..7e4c980
--- /dev/null
+++ b/tutorials/tut021_detouring.md
@@ -0,0 +1,29 @@
+# Tut 0x021
+## Detouring
+
+Detouring is a method commonly used in lua, even outside of gmod development. The idea is to redirect a function through your function first, then call the function you're redirecting at the end (or maybe the beginning, or anywhere really). Let's see an example:
+
+garrysmod/lua/autorun/detourprint.lua
+
+	local oldprint = print
+	function print(...)
+		local args = {...}
+		args[#args + 1] = "if you know what I mean..."
+		oldprint(unpack(args))
+	end
+
+The above script __replaces__ the print function, with a new function, which eventually calls the original print function, with modified arguments. The above can be done with modules in Artery as well. For example, `log.lua`'s .error() function currently only prints a message in red, it dosn't actually show what failed or why. Let's modify it to show a stack trace.
+
+garrysmod/addons/artery_rougelite/trace_errors.lua
+
+	local log = nrequire("log.lua")
+	local colors = nrequire("config/colortheme.lua") --Holds colors
+
+	local oldlog = log.error
+	function log.error(...)
+		oldlog(unpack({...}))
+		MsgC(colors.console.red,debug.traceback())
+	end
+
+
+For more information on colortheme.lua see @{colortheme.lua}, for more on debug.traceback() see [the gmod wiki](http://wiki.garrysmod.com/page/debug/traceback).