[C++-sig] tuple::size()

[David Abrahams]

From: "Ralf W. Grosse-Kunstleve" <rwgk at yahoo.com>


> If I want to know the length of a tuple, list or dict, currently I have
to
> #include a certain file with a long path.


Which file? I didn't think that was in the public library interfacee yet.
And, BTW:

    x.attr("__len__")()


> On top of that, if I am not in
> namespace boost::python, I have to type "boost::python::len(o)".

Is Koenig lookup broken on your compiler?
For MSVC, those names should be imported into std::

> Points:
>
> - Having to #include <boost/python/whatever.hpp> is cumbersome and brings
more
> code into scope than I really need.

How much stuff comes into scope all depends on how much stuff is in
whatever.hpp

> - boost::python::len() is quite a bit of clutter.

So don't use qualification.

> - .size() is what one expects to have in C++.
>
> - .size() could directly look at sq_length and thus generate less code.
>
> David, would you be very upset if I added .size() to tuple.hpp, list.hpp
and
> dict.hpp?

A little. I don't think that

    len(x)

is too cumbersome.

I want the interface for using those objects to look like the Python
interface. I don't think it's a good idea to use the C++ idioms. The next
thing you know, people will want mutable random-access iterators for
python::list, to make it act like std::vector... which would be fine if it
were possiblee (but it isn't).

-Dave

-----------------------------------------------------------
           David Abrahams * Boost Consulting
dave at boost-consulting.com * http://www.boost-consulting.com