writing a "function string" parser

Hi, I need to write a parser that will properly read and sort such strings as: "/*y=*/ sin(x)+tan(acos(log(x-1)))/atan(x)*.45462" (i figured i''d also make any whitespaces optional. basically any valid string can be expected as input. parsing this manually seems like a menial nuisance - is there some way to "group the tasks". i''m sure people have done this, and as i''ve personally never even tried writing a text parser, i''d appreciate some help. thanks in advance, Crispy