phobos and splitting things... but not with whitespace.

[simendsjo]

On Sat, 23 Jun 2012 17:39:55 +0200, Chad J  
<chadjoan at __spam.is.bad__gmail.com> wrote:

> On 06/23/2012 11:31 AM, simendsjo wrote:
>> On Sat, 23 Jun 2012 17:19:59 +0200, Chad J
>> <chadjoan at __spam.is.bad__gmail.com> wrote:
>>> http://dlang.org/phobos/std_array.html#splitter
>>
>>> The first thing I don't understand is why splitter is in /std.array/
>>> and yet only works on /strings/. It is defined > in terms of
>>> whitespace, and I don't understand how whitespace is well-defined for
>>> things besides text. Why wouldn't > it be in std.string?
>>
>> See http://dlang.org/phobos/std_algorithm.html#splitter
>>
>>> I would expect these functions to exist:
>>> auto getHead(C)(C[] s, C[] delim, ref C[] tail);
>>> auto getHead(C)(C[] s, C[] delim);
>>> auto getTail(C)(C[] s, C[] delim);
>>
>> As head is simply splitter(..)[0] and tail splitter(...)[1..$], extra
>> functions could be implemented much like this
>>
>> @property T head(T[] arr) { return arr.front; }
>> @property T[] tail(T[] arr) { return arr[1..$]; }
>>
>> ..and UFCS takes care of the rest:
>> auto fields = splitter(...);
>> auto head = fields.head;
>> auto tail = fields.tail;
>
> But I don't want tail as an array.  Assume that arr is HUGE and scanning  
> the rest of it is a bad idea.  join(arr[1..$]) then becomes a slow  
> operation: O(n) when I could have O(1).


Looking for findSplit? http://dlang.org/phobos/std_algorithm.html#findSplit