AP_Scripting: added a simple example of the load() function

libraries/AP_Scripting/examples/test_load.lua

@@ -0,0 +1,34 @@
+--[[
+ test the load function for loading new code from strings
+--]]
+
+gcs:send_text(0,"Testing load() method")
+
+-- a function written as a string. This could come from a file
+-- or any other source (eg. mavlink)
+-- Note that the [[ xxx ]] syntax is just a multi-line string
+local func_str = [[
+function TestFunc(x,y)
+  return math.sin(x) + math.cos(y)
+end
+]]
+
+function test_load()
+   -- load the code into the global environment
+   local f,errloc,err = load(func_str,"TestFunc", "t", _ENV)
+   if not f then
+      gcs:send_text(0,string.format("Error %s: %s", errloc, err))
+      return
+   end
+   -- run the code within a protected call to catch any errors
+   local success, err = pcall(f)
+   if not success then
+      gcs:send_text(0, string.format("Failed to load TestFunc: %s", err))
+      return
+   end
+
+   -- we now have the new function
+   gcs:send_text(0, string.format("TestFunc(3,4) -> %f", TestFunc(3,4)))
+end
+
+test_load()