Idea for formatting in comicget

Instead of supporting multiple formats for dates, and having to write a new function for each one (2008-09-04,0894,etc.) we should simply allow people to write a string with escape values which would represent the day month or year and also in the url itself we should insert an escape value for the number. eg.

Johnny want's some images from www.abc.com.au/images.
These images are in a number format, but look like this:
    www.abc.com.au/images/20080904-banner.jpg

They have the number before them...
So I propose we define some escape sequences which can be inserted into an overall url to show what we need to get.

eg.
%y=year
%m=month
%d=day
%N=number

So for Johnny's urls we would put a string like this:
    www.abc.com.au/%y%m%d-banner.jpg

And what if Johnny visits another site, which is similar, but the dates do not have padding zeros?
We allow to specify how many digits of the date will be shown after the escape sequence
eg.
    www.cnn.com/%y2%m1%d1-banner.jpg