On May 2, 2012, at 8:39 AM, Stuart Marks wrote:
>
> It's fun to think about how joining would work in a lambda/streamy kind of
> world, e.g.
>
> stream.infix(",").join(new StringBuilder()).toString()
>
Indeed :-) [Paul ducks as he makes up stuff!]:
String s = stream.interpose(",").reduce(new ToStringReducer());
since join can be considered a reduce operation, and the above could be
equivalent to:
String s = stream.interleave(repeat(",")).drop(1).reduce(new
ToStringReducer()); [*]
As well as:
String s = stream.join(",") // can be optimal implementation specific to
strings, String.join could defer to this
> or some such. There are a bunch of issues to consider here though, such as
> special-casing of types in the input stream, e.g., append CharSequence
> directly instead of calling toString(), treat int value as a Unicode code
> point, etc. There are also issues about the result type: StringBuilder?
> String? Appendable?
>
> As much as I like the lambda stuff, though, I don't think having stream-based
> joining will supplant the need to have a good old-fashioned
>
> String.join(",", ...bunch of strings...)
>
Yes.
Paul.
[*] interleave could support one or more streams
