You need to parse yor expression. To do this you can use a library like boost::spirit: Boost::Spirit . It could be helpful to understand how a parser works. Just search for parser in google should show you some infos regarding this.

Kimmi

As Kimmi said, you should look into a more full fledged parser for this task. The problem is that standard regular expressions do not deal well with things like nested parens; because they generally model a DFA (deterministic finite automaton). DFAs have no memory, so "counting" the nesting level becomes problematic. Parsers can express more general grammars and can be based on more powerful formalisms (like the pushdown automaton). Give some of these parsers a look and see if they serve your purpose.

Conversely, you could implement some sort of prefix tag system, where prior to an expression you detail all the of the information the regular expression parser would need to know

PhysicsActor("Content/ig_box", new BoxObject(new Vector3(2.5f), new Vector(256, 100, 256), Vector3.Zero))

might become:

[2,3,1,3] PhysicsActor("Content/ig_box", new BoxObject(new Vector3(2.5f), new Vector(256, 100, 256), Vector3.Zero))

This is just off the top of my head, and you can see how messy it might become, but the list of numbers that precedes the line tells (from left to right) how many arguments each encountered function takes. Physics Actor takes 2, BoxObject takes 3 Vector3 takes 1 and Vector takes 3. That way, every time you encounter a '(' you know how to parse the intervening expression. As you can see, this is messy, hackish, and probably not very extensible at all; I suggest you go with a proper parser :).

Cheers,
Rob

You can also use a existing script language like lua. Lua brings a working and well tested parser with it. And it is not such a hard task using luabind. Here is a short tutorial how to do that: Tutorial .

Kimmi

[Edited by - Kimmi on March 13, 2009 5:39:58 PM]