# $key = 'a1:a2:a3', $val = 'foo'
my ($key, $val) = split(/=/);

# find the number of ':' in string
my $num = map(/:/g, $key) + 1;

# create hash keys - split returns 'a1','a2', and 'a3'
# hash key creation NOT WORKING
%hash = split(/:/, $key, $num);