A little of coordination for Rosettacode

[bearophile]

If some of you has a little of time to review code, I have 
converted the very fast C memory mapped version of "Ordered 
words" to D:

http://rosettacode.org/wiki/Ordered_words#Mmap

http://rosettacode.org/wiki/Ordered_words#Memory_Mapped_Version

The C version contains several pointers that get juggled around, 
even with a negative index:

if (s[0] < s[-1]) r = 0;

So the C entry is rather bug-prone (and it doesn't compile on GCC 
Windows). The D entry is portable, and uses mostly slices and 
(non-negative) array indexes.


The D findWord function is fiddly still:

const(char)[] findWord(const char[] s) pure nothrow @safe {
     size_t wordEnd = 0;
     while (wordEnd < s.length && s[wordEnd] != '\n'
            && s[wordEnd] != '\r')
         wordEnd++;
     return s[0 .. wordEnd];
}


I think a takeWhile (similar to a Python itertools function) is 
able to replace it:

return s.takeWhile!(c => !"\n\r".canFind(c));


Using the current Phobos (but a benchmark shows with DMD it's 
slower):

const(char)[] findWord(const char[] s) pure /*nothrow*/ @safe {
     immutable wordEnd = s.countUntil!q{a == '\n' || a == '\r'}();
     return s[0 .. wordEnd >= 0 ? wordEnd : $];
}

Bye,
bearophile