Re: [boost] Variadic append for std::string

Subject: Re: [boost] Variadic append for std::string
From: Christof Donat (cd_at_[hidden])
Date: 2017-01-25 11:23:13

Hi,

Am 24.01.2017 13:12, schrieb Richard Hodges:
>> The second version I reject regardless, because it uses an overloaded
>> operator |.
> 
>> That is the adaptor API from boost::range and is the same in 
>> ranges::v3.
> It's not my invention.
> 
> I must admit that I share Hans' distaste of the pipe overloads.

As I said, this is not my invention. That notation is used with 
boost::ranges and ranges::v3 and has good chances to be part of the C++ 
standard library in future. At least the committee seems to discuss 
ranges::v3.

> I also strongly feel that .str() is an error, since it couples the 
> concepts
> of strings with joiners, or concatenators. Strings have allocators and
> traits. I feel that a free function is more decoupled, and could even 
> go in
> a separate header file to reduce complexity.

The allocator could be given with a parameter :

concat(...).str(my_allocator);

We could have a character type as template parameter, which might 
default to char:

concat(...).str<wchar>(my_allocator);

The whole discussion started with a question for a concat() like 
function, that would return std::string. Therefore I don't feel too 
embarrassed, that up to now we came up with stuff, that is coupled to 
produce strings.

> to_string(x) is better than x.str() is better than implicit conversion.

Maybe it is just my strong distaste of the name to_string(), which at 
the moment is just a feeling, no good reasons. It just feels clumsy to 
me, while .str() is in line with regular expression matches, and 
stringstreams in the standard library.

Christof