standard ranges

[Steven Schveighoffer]

On Wed, 27 Jun 2012 16:55:49 -0400, Timon Gehr <timon.gehr at gmx.ch> wrote:

> On 06/27/2012 10:22 PM, Steven Schveighoffer wrote:
>> On Wed, 27 Jun 2012 15:20:26 -0400, Timon Gehr <timon.gehr at gmx.ch>  
>> wrote:
>>
>>> There is no reason for anyone to be confused about this endlessly. It
>>> is simple to understand. Furthermore, think about the implications of a
>>> library-defined string type: it just introduces the problem of what the
>>> type of built-in string literals should be. This would cause endless
>>> pain with type deduction, ifti, string mixins, ... A library-defined
>>> string type cannot be a full string type. Pretending that it can has no
>>> value.
>>
>> Default type of the literal should be the library type.
>
> Then it is not a library type, but a built-in type. Are you planning to
> inject a dependency on Phobos into the compiler?

No, druntime, and include minimal utf support.  We do the same thing with  
AssociativeArray.

>> If you want immutable(char)[], use "abc".codeunits or equivalent.
>>
>
> I really don't want to type .codeunits, but I want to use
> immutable(char)[] everywhere. This 'library type' is just an interface
> change that makes writing nice and efficient code a kludge.

When most string functions take strings, why would you want to use  
immutable(char)[] everywhere?

>> Of course, it should by default work as a zero-terminated char * for C
>> compatibility.
>>
>> The current situation is not simple to understand.
>
> It is simple, even if not immediately obvious. It does not have to be
> immediately obvious without explanation. It needs to be convenient.

Try sorting an array of ascii characters.

>> Generic code that accepts arrays  has to special-case narrow-width  
>> strings if you plan to
>> use phobos with them in some cases. That is a horrible situation.
>>
>
> Generic code accepts ranges, not arrays. All necessary (or maybe
> unnecessary, I don't know) special casing is already done for you in
> Phobos. The _only_ thing that is problematic is the inconsistent
> 'foreach' behaviour.

Plenty of generic code specializes on arrays.

>>> alias immutable(char)[] string is just fine.
>>
>> That is technically fine, but if phobos wants to treat immutable(char)[]
>> as something other than an array, it is not fine.
>>
>> -Steve
>
> Phobos does not treat immutable(char)[] as something other than an
> array. It does not treat all arrays uniformly though.

It certainly does.  An array by definition is a random-access range.  It  
does not treat strings as random access ranges.

-Steve