[MERGE] Nested trees: CompositeTree

[Vincent Ladeuil]

>>>>> "aaron" == Aaron Bentley <aaron at aaronbentley.com> writes:

<snip/>

    >> John has been promoting a policy of explicitly naming
    >> optional parameters rather than relying on their position
    >> being unchanged.

    aaron> I don't think I've ever heard that suggested before.

It has been discussed at several occasions, from memory I'd say
during reviews, so that may explain you didn't notice.

It isn't a *requirement*, we have no way to really enforce it,
it's just that it provides some room regarding backward
compatibility.

It isn't perfect either (ever heard about 'ignore_fallbacks'
backtraces :), yet it helps.

    aaron> Is it not an API break to change the position of any
    aaron> parameter?

In the general case yes. That's exactly the reason John (and I
strongly agree and try to do the same) proposed to always specify
names for *optional* parameters.

With that rule only the *required* parameters order remains
important.

    aaron> If not, then shouldn't we specify the names of all
    aaron> parameters, not just optional ones?

Specifying names is harder to type and to read, I think the
policy is a trade-off trying to increase overall comfort, a bit
more effort now, for hopefully less effort later.

     Vincent