derpy's script loader - Global Variables
The only global variable set by DSL (besides all of its functions) is gDerpyScriptLoader, which is set to the current version of DSL.
You can use this value to conditionally support certain features of DSL, or to check for the presence of DSL when making a script that should work anywhere.
if gDerpyScriptLoader then
DrawTextInline("You can make use of DSL functions!", 3, 1)
else
TextPrintString("Support running this script without DSL.", 3, 1)
end