GDL: DEL TOP and BREAKPOINT in Macros

[Laszlo Nagy]

This may need to go to Tips & Tricks:

I dont't know how well this is known, but I just found it now:

1. If you have a DEL TOP command in a Macro, when it is executed it will delete all coordinate transformations in the calling script as well. Which means DEL TOP should be used carefully because it can give unexpected results. The best is that in a macro only the number of done coordinate transformations are deleted always.
2. I was always trying to find out how to stop a script in debug mode when it is in a macro called by the script I am debugging. It seemed I started debugging a 3D Script, went step-by-step, and the debugger always considered the Macro one step. It never got into it just continued in the calling script with the line after the CALL statement.
I found out if I place a BREAKPOINT command in the Macro the result of which evaluated to true (like BREAKPOINT DDDDD=0), then the debugger will stop in the Macro, and you can check the values of variables there.
It can come handy when looking for the reason your script does not work the way you want it.

[Anonymous]

Laszlo,
Thank you for the information.
How del top works in macros I did not know but it reminds me
of DNCs admonishment not to use del top
and this is another reason not to.
One of the reasons I rarely us the debugger is that I could not
figure out how to get it to jump into a macro.
Thanks to you I now know how to do it.
Thank you,
Peter Devlin