Function naming decoration to alert for a deepcopy in the body

[vitornesello]

It might be interesting to extend the ! concept for when a function uses deepcopy. Like this:

• function f(foo) : No side-effects
• function f!(foo) : Side effects
• function f!!(foo) : Has deepcopy and likely side-effects

deepcopy can be quite dangerous and sometimes we fall in the trap of calling a function that deepcopies an argument and then use the deepcopied argument hoping the modifications would be persistent on the structures modified by the deepcopying function.

What do you think?

[guimarqu]

I don't think it's necessary if the documentation warns the user that the function performs a deepcopy.