[RFC] I/O and Buffer Range

[Joseph Cassman]

On Sunday, 29 December 2013 at 22:02:57 UTC, Dmitry Olshansky 
wrote:
> [...]

Interesting idea. Seems to fill a need I have been facing with 
some parsing code.

Since I was unclear about how its functionality compares to 
ForwardRange I took a look through std.algorithm. If typed 
versions of lookahead/lookbehind were added it seems like 
ForwardRange could be replaced with this new range type, at least 
in certain places. For example, it seems to me that the following 
code (from the article "On Iteration" 
https://www.informit.com/articles/article.aspx?p=1407357&seqNum=7)

    ForwardRange findAdjacent(ForwardRange r){
       if (!r.empty()) {
          auto s = r.save();
          s.popFront();
          for (; !s.empty();
                r.popFront(), s.popFront()) {
             if (r.front() == s.front()) break;
          }
       }
       return r;
    }

also could be written as

    BufferedRange findAdjacent(BufferedRange r) {
       for(;!r.empty;r.popFront()) {
          if(r.front == r.lookahead(1)[0]) break;
       }
       return r;
    }

Perhaps the mark and/or slice functionality could be leveraged to 
do something similar but be more performant.

If anyone can see how the new range type compares to ForwardRange 
that would be cool.

Joseph