TDPL reaches Thermopylae level

[Justin Johansson]

Chris Nicholson-Sauls Wrote:

> Andrei Alexandrescu wrote:
> > Bill Baxter wrote:
> >> On Mon, Oct 26, 2009 at 11:51 AM, Andrei Alexandrescu
> >> <SeeWebsiteForEmail at erdani.org> 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.)
> >>
> >> So a common way to convert wchar to char might then become 
> >> ""~myWcharString?
> >>
> >> That seems kind of odd.
> > 
> > Well, I guess. In particular, to me it's not clear what type we should 
> > assign to a concatenation between a string and a wstring. With ~=, it's 
> > much easier...
> > 
> 
> My intuition would be to expect the same as adding an int to a byte: you get an int. 
> Concatenating a string and a wstring should yield a wstring; ie, encode to the wider of 
> the two types.
> 
> -- Chris Nicholson-Sauls

Though I'm sure Shannon would say that the number of bits of intrinsic information
contained in the same sequence of Unicode codepoints is exactly the same whether
it be encoded as a string or a wstring.  Accordingly my intuition is that some rule
based upon left-to-right associativity would be more apt.  You could then concatenate
a wstring (on the rhs) to an empty string (on the lhs) to convert the wstring to a string
or vica versa.

Cheers
Justin Johansson