Forums Scripts & Popups text modifieing

yes
i have a variable for example:
%a = "aaa [1:1:1]bbb [1:2:1]"
i want to make it :
%a [ $+ [ 1 ] ] = "aaa [1:1:1]"
%a [ $+ [ 2 ] ] = "bbb [1:2:1]"

but i dont know how to separate aaa [1:1:1] & bbb [1:2:1] cause there is no space between them