On Wednesday, 2 October 2013 at 13:09:34 UTC, Daniel Davidson
wrote:
1. If a variable is never mutated, make it const, not immutable.
2. Make the parameter reference to immutable if that is how you
will use it anyway. It is fine to ask a favor from the caller.
...
I think guideline 1 should be about "arguments" not "variables".
Functions should take const arguments, so they can be called with
mutable and immutable values.
I would rephrase the second guideline as: "Never dup or idup an
argument to make it mutable or immutable, but require the caller
to do this (might be able to avoid it)".
For more guidelines:
3. Return value, which are freshly created, should never be
const. They should be mutable or immutable.
Basically, I cannot come up with a case, where const would be
preferable to mutable and immutable. Maybe someone is able to
find a good example? Of course, this does not hold for returned
values, which are retrieved from somewhere (array,container,etc).
In this case, I have no general advice.
4. Data structures should not restrict themselves to be mutable,
const, or immutable.
This is a noble goal, which in reality is probably either trivial
or impossible. So I am not sure, if it is worthy to be called a
guideline.
