[Issue 15759] New: chunks should work with only an input range

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=15759

          Issue ID: 15759
           Summary: chunks should work with only an input range
           Product: D
           Version: D2
          Hardware: x86_64
                OS: Linux
            Status: NEW
          Severity: enhancement
          Priority: P1
         Component: phobos
          Assignee: nobody at puremagic.com
          Reporter: greeenify at gmail.com

It would be nice if `chunks` would accept only an InputRange too. Let me show
you a common pattern that I often use:

// iterate over two lines in a pair and compute the difference between them
// 1 2
// 2 3
// => 2
stdin.byLineCopy.map!(x => x.splitter(' ').map!(to!int)).chunks(2)).map(x =>
  abs(x.frontPop - x.front);
);

This currently doesn't compile, because `chunks` doesn't buffer, it saves the
state of the forward range. However adding support for normal Input Ranges
shouldn't can easily done using a local buffer - I already wrote the code at
some point:

https://github.com/greenify/d-itertools/blob/4afbc804e8b50c797fa206969dc3b4934911a0b9/source/splitwise.d

I would be happy to wrap this up nicely and bring it into a phobos shape - any
thoughts/concerns?

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