Often times I don't have any problem with interpreting or speaking but I do wonder about the function of this reduction. The example sentence is as follows;
You can have all the beer you want then, assuming you buy it yourself.
In the second part after the coma, what is ASSUMİNG function? I can't separate the construction as a subj verb etc. I don't think it is a gerund but i usually come across with that structure.