we can pass info to and retrieve info from a form like this:
do form with arg1,arg2 to result
which is similar to calling a function:
result = form(arg1,arg2)
when i am developing a form, i often need to change the number of input and output arguments, which means i need to constantly adjust the form calling interface.
by using a parameter object as an input/output mechanism simplifies it like below:
loparam = createobject('empty')
do form with loparam
also the use of parameter object makes it flexible in when and where to assign the output value, i.e. not restricted to returning a single entity in the unload event of the form.
i have made a screencast showing that here at showmedo.com.