people[name=="Andrew"].friends ~= peter

[Antonio]

Reading my posted message, I felt bad about misspelling.   Here you are 
a rewritten paragraph:
You makes me think about:  my conclusion is that I commited an error 
supposing than ![ ] must "return" an aggregate object... It's more clean 
to change the point of view to a "compiler" stament:  the result is, 
basically, a set of iterations over an stament... I explain this clearly 
in this new fools proposal :-)