Re: [Boost-users] A library for "string chains"?

Subject: Re: [Boost-users] A library for "string chains"?
From: Jan Herrmann (jherrmann79_at_[hidden])
Date: 2014-08-18 10:04:36

On 18.08.2014 10:09, Gordon Woodhull wrote:
>
>
>>> On Aug 18, 2014, at 2:46 AM, Jan Herrmann <jherrmann79_at_[hidden]> wrote:
>>>
>>> On 15.08.2014 23:52, Richard wrote:
>>> [Please do not mail me a copy of your followup]
>>>
>>> Jan Herrmann <jherrmann79_at_[hidden]> spake the secret code
>>> <53EDB252.9060903_at_[hidden]> thusly:
>>>
>>>>> On 14.08.2014 03:37, Richard wrote:
>>>>> Now the question remains... is there something that already exists
>>>>> that provides a string_view from a vector of string_ref's?
>>>>
>>>> Range with
>>>> http://www.boost.org/doc/libs/1_56_0/libs/range/doc/html/range/reference/utilities/join.html
>>>> could help.
>>>
>>> Hmm... looks interesting.  Obviously that could be used to get a
>>> single iterator over two string_ref's.
>>>
>>> If I have a chain of string_ref's r1...rN, it looks like I'd have to do:
>>>
>>> join(r1, join(r2, join(r3, join(r4, ..., join(rN-1, rN) ...)))
>>>
>>> Which doesn't look promising, but I'll give it a go.
>>
>> I think you will loose an O(1) indexed access but that might not be a problem. To join a container of string_refs std::accumulate could help.
>
> Believe each join type is unique, and type erasure on containers is usually non-performant, so the best you could do is fusion::accumulate - if your sequences were compile-time, which they are clearly no).
>
> The classic data structure for this stuff is a rope, but I don't know of a rope that refers to an outside buffer... :-(
>
> Cheers
> Gordon
>

Ok my mistake. So I think a rope for string_ref's has to be implemented. 
I found twines (http://llvm.org/docs/doxygen/html/Twine_8h_source.html) 
which look like a rope of variants of string_ref like types.

Jan Herrmann