On Fri, Sep 8, 2017 at 1:30 AM, Steve D'Aprano <steve+pyt...@pearwood.info> wrote: > On Fri, 8 Sep 2017 12:28 am, Chris Angelico wrote: > >> languages without mutable objects don't >> really care whether they're pass-by-X or pass-by-Y. > > Only if you don't care about efficiency. > > Believe me, the first time you pass a five gigabyte array to a function using > pass-by-value, on a machine with only six gigabytes of memory, you'll care. > > Preventing that sort of thing is probably why arrays aren't first-class values > in C, and you cannot pass an array as argument, only a pointer to an array. > But > Pascal will happily assume you know what you're doing if you declare an array > parameter without "var", and copy the whole array.
Right - but sharing (in whatever form) is a pure optimization, with no visible semantics. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
