Sarge, what you ask for makes little sense.
Theres a Fuction code lump that you could be after. For example;
...
repeat
test()
forever
...
function test()
'Do what ever in here
end function
But if what i suspect your after, is some way for making your own special statement code, like <if,else,endif>, <select,case,default,end select> and <repeat,until>. If thats the case, then theres no way to do it and there is no need to either. The current statement blocks are designed so you can expand them how you desire, and they can be made to cover everything a programmer would want to do.