[range] Best way to construct a std::set from a range?

Gabriel Redner

3 Mar 2010 3 Mar '10

12:26 a.m.

If I have a pair of iterators, I can construct a set like so: std::set<SomeType> s(it1, it2); If instead I have a range, I can adapt it like so: std::set<SomeType> s(boost::begin(range), boost::end(range)); However, my range object is being constructed on the fly. I'd like to be able to do: std::set<SomeType> s(MakeRange(args)); But clearly this is not supported by the library. It seems I need to store the range object in a variable in order to do this, which defeats the syntax-simplifying benefits of using ranges. Can this be avoided? Are there some recommended no-overhead tricks for doing this that achieve a clean syntax? Implicit conversions? Explicit "ToSet" conversion functions? Can boost.assign be of help? (My initial reading of the assign documentation suggests not, but perhaps I'm missing something). I'm also not averse to a macro so long as it looks "language-like," but so far I haven't produced anything satisfactory. Has anyone else wrestled with this one and come out victorious? Thanks, -Gabe

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Mathias Gaunard

3 Mar 3 Mar

3:54 p.m.

New subject: [range] Best way to construct a std::set from a range?

Gabriel Redner wrote:

...

If I have a pair of iterators, I can construct a set like so:

std::set<SomeType> s(it1, it2);

If instead I have a range, I can adapt it like so:

std::set<SomeType> s(boost::begin(range), boost::end(range));

However, my range object is being constructed on the fly. I'd like to be able to do:

std::set<SomeType> s(MakeRange(args));

what about template<typename Container> void assign_range(Container& c, const Range& r) { c.assign(begin(r), end(r)); } std::set<SomeType> s; assign_range(s, MakeRange(args));

Gabriel Redner

6:43 p.m.

New subject: [range] Best way to construct a std::set from a range?

Sure, that works - I was hoping for something that fits naturally on one line, though. Thanks, -Gabe On Wed, Mar 3, 2010 at 10:54 AM, Mathias Gaunard wrote:

...

Gabriel Redner wrote:

...
If I have a pair of iterators, I can construct a set like so:

std::set<SomeType> s(it1, it2);

If instead I have a range, I can adapt it like so:

std::set<SomeType> s(boost::begin(range), boost::end(range));

However, my range object is being constructed on the fly. I'd like to be able to do:

std::set<SomeType> s(MakeRange(args));

what about

template<typename Container> void assign_range(Container& c, const Range& r) { c.assign(begin(r), end(r)); }

std::set<SomeType> s; assign_range(s, MakeRange(args));

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OvermindDL1

4 Mar 4 Mar

5:37 a.m.

New subject: [range] Best way to construct a std::set from a range?

On Wed, Mar 3, 2010 at 11:43 AM, Gabriel Redner wrote:

...

Sure, that works - I was hoping for something that fits naturally on one line, though.

Well, you could use phoenix2 for a one-liner: assign(arg1, begin(arg2), end(arg2))(s, MakeRange(args))

Sebastian Theophil

10:24 a.m.

New subject: [range] Best way to construct a std::set from arange?

Or you could do std::set<SomeType> s = boost::copy_range< std::set<SomeType> >( range );

...

-----Original Message----- From: boost-users-bounces@lists.boost.org [mailto:boost-users- bounces@lists.boost.org] On Behalf Of OvermindDL1 Sent: Donnerstag, 4. März 2010 06:38 To: boost-users@lists.boost.org Subject: Re: [Boost-users] [range] Best way to construct a std::set from arange?

On Wed, Mar 3, 2010 at 11:43 AM, Gabriel Redner wrote:

...
Sure, that works - I was hoping for something that fits naturally on one line, though.

Well, you could use phoenix2 for a one-liner: assign(arg1, begin(arg2), end(arg2))(s, MakeRange(args)) _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

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Jeff Flinn

6 Mar 6 Mar

12:48 a.m.

New subject: [range] Best way to construct a std::set from arange?

Sebastian Theophil wrote:

...

Or you could do

std::set<SomeType> s = boost::copy_range< std::set<SomeType> >( range );

Cool, where's boost::copy_range defined? This should be usable in an initializer list as well I presume. Jeff

Sebastian Theophil

8 Mar 8 Mar

2:52 p.m.

New subject: [range] Best way to construct a std::set fromarange?

Hi Jeff, I'm still using boost 1.35 and boost::copy_range is defined in boost\range\iterator_range.hpp Regards Sebastian

...

-----Original Message----- From: boost-users-bounces@lists.boost.org [mailto:boost-users- bounces@lists.boost.org] On Behalf Of Jeff Flinn Sent: Samstag, 6. März 2010 01:49 To: boost-users@lists.boost.org Subject: Re: [Boost-users] [range] Best way to construct a std::set fromarange?

Sebastian Theophil wrote:

...
Or you could do

std::set<SomeType> s = boost::copy_range< std::set<SomeType> >( range );

Cool, where's boost::copy_range defined? This should be usable in an initializer list as well I presume.

Jeff

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Nat Goodspeed

3 Mar 3 Mar

11:41 p.m.

Gabriel Redner wrote:

...

If I have a pair of iterators, I can construct a set like so:

std::set<SomeType> s(it1, it2);

If instead I have a range, I can adapt it like so:

std::set<SomeType> s(boost::begin(range), boost::end(range));

However, my range object is being constructed on the fly. I'd like to be able to do:

std::set<SomeType> s(MakeRange(args));

Have you looked at range_ex? http://www.boostpro.com/vault/index.php?action=downloadfile&filename=range_ex.zip&directory=Algorithms& I think this has been reviewed, but I don't remember its current "official" status at the moment.

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participants (6)

Gabriel Redner
Jeff Flinn
Mathias Gaunard
Nat Goodspeed
OvermindDL1
Sebastian Theophil