formatting a list to drive a line object

    Sep 19 2012 | 10:40 am
    hi everyone,
    i'd like to sweep a sine tone from one specified frequency to another specified frequency, in a certain number of seconds.
    i'd like all three parameters to be things i can just type into a number box and hit "go".
    seems simple enough, but i can't figure out how to format these three number boxes into a message that [line] understands. maybe just because the comma is missing between the first value and the second value?
    the patch here isn't working: the comma isn't being appended to the first value as i'd hoped.
    could someone give me a hint to point me in the right direction?
    many thanks!