On Sunday, 27 October 2013 at 08:35:11 UTC, Jonathan M Davis
wrote:
On Sunday, October 27, 2013 09:14:28 Nicolas Sicard wrote:
On Sunday, 27 October 2013 at 07:44:06 UTC, Jakob Ovrum wrote:
> On Saturday, 26 October 2013 at 21:23:13 UTC, Gautam Goel
> wrote:
>> Dumb Newbie Question: I've searched through the library
>> reference, but I haven't figured out how to extract a
>> substring from a string. I'd like something like
>> string.substring("Hello", 0, 2) to return "Hel", for
>> example.
>> What method am I looking for? Thanks!
>
> There are a lot of good answers in this thread but I also
> think
> they miss the real issue here.
I don't think so. It's indeed worth noticing that Phobos'
algorithms work with Unicode nicely, but:
a) working on indices is sometimes the actual functionality you
need
Sometimes, but it usually isn't. If you find that you
frequently need to use
indices for a string, then you should probably rethink how
you're using
strings. Phobos aims at operating on ranges, which rarely means
using indices,
and _very_ rarely means using indices on strings. In general,
indices only get
used on strings when you're trying to optimize a particular
algorithm for
strings and make sure that you slice the string so that the
result is a string
rather than a wrapper range.
+1
Also, I think if users need to get UTF indices in their own code,
it's indicative of either a) Phobos lacking an (optimized)
algorithm, or b) the user is doing something extremely niche that
Phobos can't aim to cover generically.
Sure, indexing strings can be very useful, but they way that
Phobos is
designed does not lend itself to using string indices (quite
the opposite in
fact), and in my experince, using string indices is rarely
needed even when
doing heavy string manipulation.
And Phobos is better off for it!
I don't know if we do a good enough job of educating users about
Unicode and its implications though, assuming this is a
responsibility of the D community towards new D users.
c) do they really handle grapheme clusters? (I don't know)
I believe that that sort of thing is properly supported by the
updated std.uni
in 2.064, but it is the sort of thing that you have to code
for. Phobos as a
whole operates on ranges of dchar - which is correct most of
the time but not
enough when you need full-on grapheme support. I haven't yet
looked in detail
at what std.uni now provides though. I just know that it's
added some grapheme
support.
- Jonathan M Davis
The new std.uni supports all the grapheme-related functionality
you would ever need (as far as I can tell), but the nice thing is
that most code doesn't need to use it to be Unicode-correct. i.e.
you don't need to be "aware" of grapheme clusters to not break
them in the vast majority of code domains.
