On Tuesday, 23 June 2015 at 06:49:50 UTC, Daniel N wrote:
On Tuesday, 23 June 2015 at 01:07:17 UTC, Jonathan M Davis
wrote:
No, you can't guarantee that an auto ref parameter won't be
mutated, but auto ref clearly indicates that you intend to
accept both lvalues and rvalues, meaning that it would be
stupid to be writing the function with the idea that you would
be passing in an argument which would be mutated. ref on the
other hand clearly indicates the intention to mutate the
argument.
- Jonathan M Davis
That is why, as a good API designer, you'd express that fact by
adding const ontop of it, i.e. const ref.
Which does not generally work in D. It can in some cases, but
const is so restrictive in D that you simply cannot use it just
because you don't intend to mutate a variable. Too many types
won't work with const, and many types _can't_ work with const.
const has its uses, but you have to be careful with it, and in
the general case, that means that you can't put it on function
parameters just to indicate that the function argument is not
going to mutated.
- Jonathan M Davis
