fixed list combinatorics

Hi list,

I am having a bad day and would really like some help (the coffee hasn't).

I have a list that looks like:
my @list = (1,2,3,4);

I would like to generate all patterns that follow:
1
2
3
4
12
123
23
34
234
1234


The list can be of any length and the next number in the list must be the
current number +1 ( i am not working with numbers - i think it is easier to
explain this way).

How do I do this? I did look at the Combinatorics module however it does
not impose fixed ordering as far as I can see.

Thanks