Thanks for the kind explanations and references that I had missed, seems
clear to me now.
As a footnote, I was looking for a way to enforce Matlab-like behaviour,
that is changing the contents of an array argument inside a function is
invisible to the caller.
Unsuccessful attempt:
function f!(x)
x=x # <== does not copy x, it seems to get optimized away
x[:]=x+1 # <== this is still visible to the caller
end
but
function f(x)
x=copy(x) # <== copies x in function scope, for numeric arrays x=x+0 works
also
x{:]=x+1 # <== this is now invisible to the caller
end
