One of the main tasks in 8.x has been to open up DataEase programming. Since the beginning of DataEase has derivations, scripts, DQL's etc been "non changeable" i.e. they will only exist in the form designed by the developer when designing the applicaiton.

In DE8 we want to make programming flexible, so that an application could evolve outside its fixed design.

The first part we attacked was DQL with ExecDQL which opened DataEase wide open, but for some strange reason it took us a while to realise that it would be very neat if we could simply fire a Derivation on the go too.

ExecDerivation is basically the same as the derivation on a Field/Column or the Action: Execute Derivation/Function but with one significant difference...

It will interpret a string and execute it on the fly.

This means that you can now very easily change the action on a button based on things that happen in your application.

For instance you can have this derivation on all your close buttons.

ExecDerivation(GetVar("CloseAction"))

Then you can add the following to the OpenDocument action on your forms.

+SetVar("CloseAction","DocumentOpen(/'DocumentToReturnToHere/')+DocumentClose()")

Use your imagination...

Derivation: Any allowable derivation according to the rules of BRL in DataEase.