Is there an easy way to collect terms by powers of a variable in an expression? Ie. I have an expression on the stack that looks like this

A*x^2 + A*x + B*x + C

I want to group (something like GROUP(expression,'x') ) it by powers of x, so that it looks like this:

Ax^2 + (A+B)x + C

and not something like A(x^2 + x) + Bx + C which FACTOR/SIMPLIFY/COLLECT often give me.

It would also be handy if I could extract a vector of coefficients from that expression: [A A+B C].

If anyone knows how to do this please help me out :)