I can\'t find a solution (here and on the web) for simply selecting/inserting/deleting stuff surrounded by dots (a common case in development) :
someobje
I'm not absolutely sure (I learn new vim features everyday) but I think you can't select between dots with text-objects. So, if it's a common case for you maybe you can create a mapping like the following:
nnoremap d t.vT.
Just to avoid typing five characters each time you need to select between dots.