TDPL reaches Thermopylae level

[Andrei Alexandrescu]

Jeremie Pelletier wrote:
> Andrei Alexandrescu wrote:
>> Bill Baxter wrote:
>>> On Mon, Oct 26, 2009 at 8:47 AM, Jeremie Pelletier 
>>> <jeremiep at gmail.com> wrote:
>>>> Andrei Alexandrescu wrote:
>>>>> 303 pages and counting!
>>>>>
>>>>> Andrei
>>>> Soon the PI level, or at least 10 times PI!
>>>>
>>>
>>> A hundred even. ;-)
>>
>> Coming along. I'm writing about strings and Unicode right now. I was 
>> wondering what people think about allowing concatenation (with ~ and 
>> ~=) of strings of different character widths. The support library 
>> could do all of the transcoding.
>>
>> (I understand that concatenating an array of wchar or char with a 
>> dchar is already in bugzilla.)
>>
>>
>> Andrei
> 
> I don't know if thats a good idea, its better when string encoding is 
> explicit so you know where your reallocations are.

The beauty of it is that reallocation with ~ occurs anyway, and with ~= 
is anyway imminent, regardless of the character width you're reallocating.

Allowing concatenation of strings of different widths is a nice way of 
acknowledging at the language level that all character widths are 
encodings of abstract characters.

> ie if I know some routine will have to convert a utf16 parameter to utf8 
> to append it to a string, then ill try and either make it output utf16 
> or input utf8. If its implicit its much harder to find and optimize 
> these cases.
> 
> to!string() is easy enough to use anyways.
> 
> But it could be good to add a range type that does this with multiple 
> opAppend/opAppendAssign overloads.

One problem with

s ~= to!string(someDstring);

is that it does two allocations instead of one.


Andrei