On Sat, 15 Jan 2011 13:19:34 -0500, Andrei Alexandrescu
<[email protected]> wrote:
On 1/15/11 11:15 CST, Steven Schveighoffer wrote:
On Fri, 14 Jan 2011 12:03:28 -0500, Andrei Alexandrescu
<[email protected]> wrote:
On 1/14/11 5:06 AM, Steven Schveighoffer wrote:
On Thu, 13 Jan 2011 23:03:35 -0500, Steven Wawryk
<[email protected]>
wrote:
Because at the code-point level it *isn't* a random-access range and
the index makes no sense at the code-point level, only at the
code-unit level. It's encouraging the confusion of 2 distinctly
different abstractions or "views" of the same data. All the slicing
and indexing you're artificially putting in the code-point range is
already available in the code-unit range, and its only benefit is to
allow the user to save typing ".data".
I respectfully disagree. A stream built on fixed-sized units, but with
variable length elements, where you can determine the start of an
element in O(1) time given a random index absolutely provides
random-access. It just doesn't provide length.
I equally respectfully disagree. I think random access is defined as
accessing the ith element in O(1) time. That's not the case here.
I'd actually go as far as saying that any container you can do a quick
lookup given an index (O(lgn) or better) is random-access. For example,
a dictionary file of english words sorted alphabetically can look up any
word definition in O(lgn) time, but you can't look up the nth word in
O(lgn) time.
Here you are trying to equate a dictionary (map/hashtable) with an
otherwise unstructured variable length encoded array. I don't think
there is much similarity.
I see a lot of similarity. Both have sparsely populated indexes. Both
cannot determine their length unless you save it separately. Both are
encoded on an array of fixed-length elements. Both store their data
sorted by index.
The difference is that the index is a size_t for one and a string for the
other.
What do you call this type of container if not random access? Indexed
maybe? Whatever term you call it, I'd call it that, and say opIndex
belongs for that container.
-Steve
I'm not sure how you can call it, but it's definitely not random access.
The former complaint was "because this != random access, opIndex doesn't
belong."
If we can get past the terminology of what this is, I think at least
opSlice belongs and I still think opIndex belongs. Can you not see the
value of 'give me the element at index X' giving you back a full element
and not just a code-unit?
If opIndex doesn't belong unless it's a random access container (i.e.
array), then we should get rid of the operator for hashes and sorted trees.
-Steve
