Interesting paper. I hope he posts the full version...Does anyone have any idea about which programs he is talking about?
One of them is MetaStock, I've got a copy and it does have those flaws.
Most MS users have learnt to work round them by not using the "Enhanced System Tester" as it is called (I dread to think what it was before it was "enhanced"!) and use instead the "Explorer" (the scanner) with indicators.
Two programmers have done excellent work on this subject: Jose Silva and Roy Larsen.
The other system is probably TradeStation, which was the one used by M.Harris in his first two books, and which language is much more powerful than MetaStock's.
Eduardo.