D's confusing strings (was Re: D on hackernews)

[Graham Fawcett]

On Wed, 21 Sep 2011 11:39:03 -0500, Andrei Alexandrescu wrote:

> On 9/21/11 10:16 AM, Christophe wrote:
>> Timon Gehr , dans le message (digitalmars.D:144889), a écrit :
>>> unicode natively. Yet the 'D strings are strange and confusing'
>>> argument comes up quite often on the web.
>>
>> Well, I think they are. The ptr+length stuff is amasing, but the
>> behavior of strings in phobos is weird.
>>
>> mini-quiz: what should std.range.drop(some_string, 1) do ? hint: what
>> it actually does is not what the documentation of phobos suggests*...
>>
>> Strings are array of char, but they appear like a lazy range of dchar
>> to phobos. I could cope with the fact that this is a little unexpected
>> for beginners. But well, that creates a lot of exceptions in phobos,
>> like the fact that you can't even copy a char[] to a char[] with
>> std.algorithm.copy. And I don't mention all the optimization that are
>> not/cannot be performed for those strings. I'll just remember to use
>> ubyte[] wherever I can...
> 
> String handling in D is good modulo the oddities you noticed. What would
> make it perfect would be:
> 
> * Add property .rep that returns byte[], ushort[], or uint[] for char[],
> wchar[], dchar[] respectively (with the appropriate qualifier).
> 
> * Replace .length with .codeUnits.
> 
> * Disallow [n] and [m .. n]
> 
> This would upgrade D's strings from good to awesome. Really it would be
> a dream come true. Unfortunately it would also break most D code there
> is out there. I don't see how we can improve the current situation while
> staying backward compatible.
> 
> 
> Andrei

1. Let "string" remain an alias for "immutable(char)[]", and introduce a 
new struct, "text!charType", that does the awesome stuff; provide good 
conversion routines and casts between text instances and old-school 
strings.

2. Provide an awesome "std.text" library for the text type and related 
operations, absorbing std.uni and other similar modules. Adapt Phobos to 
take "text" in virtually every function that currently expects a "string".

3. ...

4. Profit.

Graham