AP_Scripting: add fast param bindings and example

libraries/AP_Scripting/examples/param_get_set_test.lua

@@ -1,6 +1,19 @@
 -- This script is a test of param set and get
 local count = 0
 
+-- for fast param acess it is better to get a param object,
+-- this saves the code searching for the param by name every time
+local VM_I_Count = Parameter()
+if not VM_I_Count:init('SCR_VM_I_COUNT') then
+  gcs:send_text(6, 'get SCR_VM_I_COUNT failed')
+end
+
+-- returns null if param cant be found
+local fake_param = Parameter()
+if not fake_param:init('FAKE_PARAM') then
+  gcs:send_text(6, 'get FAKE_PARAM failed')
+end
+
 function update() -- this is the loop which periodically runs
 
   -- get and print all the scripting parameters
@@ -40,6 +53,18 @@ function update() -- this is the loop which periodically runs
   end
 
   
+  -- increment the VM I count by one using direct accsess method
+  local VM_count = VM_I_Count:get()
+  if VM_count then
+    gcs:send_text(6, string.format('LUA: SCR_VM_I_COUNT: %i',VM_count))
+    if not VM_I_Count:set( VM_count + 1) then
+        gcs:send_text(6, string.format('LUA: failed to set SCR_VM_I_COUNT'))
+    end
+  else
+    gcs:send_text(6, 'LUA: read SCR_VM_I_COUNT failed')
+  end
+
+
   count = count + 1;
 
   -- self terminate after 30 loops

libraries/AP_Scripting/generator/description/bindings.desc

@@ -248,6 +248,13 @@ singleton AP_Param method get boolean string float'Null
 singleton AP_Param method set boolean string float -FLT_MAX FLT_MAX
 singleton AP_Param method set_and_save boolean string float -FLT_MAX FLT_MAX
 
+include AP_Scripting/AP_Scripting_helpers.h
+userdata Parameter method init boolean string
+userdata Parameter method get boolean float'Null
+userdata Parameter method set boolean float -FLT_MAX FLT_MAX
+userdata Parameter method set_and_save boolean float -FLT_MAX FLT_MAX
+
+
 include AP_Mission/AP_Mission.h
 singleton AP_Mission alias mission
 singleton AP_Mission scheduler-semaphore