I can not manage to do calculation in command line. It seems it's not possible.
For example, i start a new line at 100,50 and i'd like to set next points like this

x+100,y+200

where x is the previous x position (100 for the example) and y the previous y position (50 for the example), setting the next point to x=100+100->200 and y=50+200->250

I had a look to the DS help and through the iQuestions but did not find anything.
Does anybody have a suggestion?

If it's not possible, it would be grate to add that kind of functionalities.

Thanks