Subject: Re: [boost] [Range] New I/O functions for ranges
From: Indiana (indi.in.the.wired_at_[hidden])
Date: 2014-10-05 11:46:43
On 14-10-01 05:00 AM, Paul A. Bristow wrote:
> You may well be right, but I'm only reporting what I found were my 'needs'.
>
> You can show how to wrap write_all output (with 'smart' delimiter - no ugly
> trailing commas!) with prefix and suffix strings, that will probably be fine.
Yeah, sure - actually write_all() does that right out of the box:
o << "prefix" << write_all({1,2,3}, "delimiter") << "suffix";
// Prints: "prefix1delimiter2delimiter3suffix";
So:
o << '{' << write_all({1,2,3}, ',') << '}';
// Prints: "{1,2,3}"
> I only meant a string in C++ syntax like
>
> int[10] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
>
> that you have shown is possible.
Actually, you can probably generalize that. The following code isn't
tested, but:
template <typename Range, typename CharT, typename Traits>
void format_range(std::basic_ostream<CharT, Traits>& o, Range&& r)
{
using std::begin;
using std::end;
using value_type = std::decay_t<typename range_value<Range>::type>;
std::basic_ostringstream<CharT, Traits> oss{};
oss.imbue(std::locale::classic());
oss << boost::typeindex::type_id<value_type>().pretty_name();
oss << '[' << std::distance(begin(r), end(r)) << ']' << " = ";
oss << '{' << write_all(std::forward<Range>(r), ", ") << "};\n";
o << oss.str();
}
Calling format_range() for any range type should give the output you
want, more or less, dependent on the range value type.
auto v = std::vector<int>{1,2,3};
cout << format_range(v); // Prints: "int[3] = {1, 2, 3};"
auto const a = std::array<double, 4>{1.1, 2.2, 3.3, 4.4};
cout << format_range(a); // Prints: "double[4] = {1.1, 2.2, 3.3, 4.4};"
> Now you need some enthusiastic users to support you on a review ;-)
Yeah? I'm not sure how the process goes here. Do I make a pull request
on the Boost.Range repository and implement the changes? Or do I
implement the idea separately, so people can experiment and mess around
with it, and only after it's passed review try to integrate it with the
rest of the library? Do I get in touch with the Boost.Range maintainers
(seems to be Thorsten Ottosen and Neil Groves)?