Giving command arguments with string variables

I am trying to create a particle object with several particles. I am wanting to pass a string to the particle command like:

particle $parts;

This is of course not working. The error I am receiving is:

Error: No object matches name: -p 0 0 0 -p 3 0 0

Any help would be appreciated.
Colin

This works...

string $test="-p 0 0 0 -p 3 0 0";

eval("particle "+$test);