replaceFirst, findPieces, and takeExactly

[Andrei Alexandrescu]

OK, I added replaceFirst:

http://d-programming-language.org/cutting-edge/phobos/std_array.html#replaceFirst

http://www.dsource.org/projects/phobos/changeset/2365

I've also added two crucial abstractions that finally quench my many 
sleepless nights following my Boostcon keynote. Back then people said 
that STL's find() is better than D's find() because the former returns 
an iterator that can be combined with either the first iterator to get 
the portion before the match, or with the last iterator to get the 
portion starting at the match. D's find() only gives you the portion 
after the match.

The first abstraction is the takeExactly() function:

http://d-programming-language.org/cutting-edge/phobos/std_range.html#takeExactly

That function allows you to pick a determined number of elements from a 
range, assuming the range is never shorter than that. That sounds a bit 
obscure, but plays a pivotal role in findParts() (which is the name I 
settled on for the equivalent of Python's partition()):

http://d-programming-language.org/cutting-edge/phobos/std_algorithm.html#findParts

There are many nice things about findParts() that make it feel whole: 
all parts have lengths, their types are the best possible given the 
input, and the amount of information conveyed is maximized.

The implementations of findParts and takeExactly are simple and elegant too:

http://www.dsource.org/projects/phobos/changeset/2365


Andrei