Indeed you must write some lines! ;)
http://www.openscad.org
A French tutorial ;)
http://fablab-lannion.org/wp-content/tutos/openscad/#/pageDeGarde

Hi Hamish - in the future I would also like to add more support for scripting as a way of procedural object generation, which is indeed a form of parametric building but it has a high level of complexity for someone to learn. So it would likely be something that could optionally be used but not likely to be the only way to do parametric editing.

Parametric editing that is based off of editing things that you previously drew would probably be able to be used by a wider variety of people than one that required coding.

- Michael

"... but not likely to be the only way to do parametric editing."

Yes. Please take into consideration also something like the "Components" from Sketchup or Blocks from Rhino, or iLogic from Inventor. They are also very powerful parametric design approaches.

MoI can be more powerful than Sketchup (already is in many ways) but is drawn back by the lack of "components". Personally I think that if the MoI will have something similar to components will be a serious option for replacing Sketchup.