[boost] Re: Namespaces vs. directory placement

From: Jonathan Turkanis (technews_at_[hidden])
Date: 2004-12-29 02:08:41

David Abrahams wrote:
> Jonathan Turkanis wrote:
>> Jonathan Turkanis wrote:
>>
>>> Okay, if there are no objections, this is what I'll do.
>>
>> This didn't come out quite right -- I know that Daryle has objected.
>>
>> I guess I mean: given the fact that the namespace-directory
>> convention has already been widely violated, if there are no further
>> objections I'll keep the library in the iostreams directory but use
>> the io namespace.
>
> I didn't see the whole thread, but we ought to try to avoid violating
> the convention any more than it has been.  As Boost grows, this
> becomes more important.  What's wrong with a namespace
> boost::iostreams?  You can always introduce an alias for backward
> compatibility.

Since you didn't see the whole thread, let me quote myself:

Jonathan Turkanis wrote:
> I would greatly prefer to use the namespace  "boost::io" because:
>
>    (i) it is much shorter than "boost::iostreams"; while it is possible to use
> an alias to shorten it, I'd hate to make users do this when there is a
perfectly
> suitable short name available.
>    (ii) there currently are not many declarations in the namespace
"boost::io",
> so there is not much chance of collisions
>    (iii) it is a more accurate discription of the library, since the core
> infrastructure is independent of the standard iostreams library and might be
> used without streams, e.g., for async i/o.

(i) is particularly important, since the documentation will contain a lot of
tutorial material in which the namespace qualification can't be omitted, e.g.,

    template<typename Sink>
    void put(Sink& dest, int c)
    {
        if (c == '\n')
            col_no_ = 0;
        else {
            if (col_no_ >= line_length_)
                this->put(dest, '\n');
            ++col_no_;
        }
        boost::io::put(dest, c);
    }

The occurence of boost::io::put in the above example has to be qualified, since
otherwise it will refer to the member function being defined. I worry that
having to use a long namespace name or to introduce a namespace alias in a high
percentage of the examples will make the documentation harder to follow, and the
library harder to learn.

If I have to choose, then, I would much rather use the namespace io and move the
library back to boost/io than use the namespace iostreams.

Jonathan