Re: State of the compiler market

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On 30/06/2017 09:34, J-P. Rosen wrote:
> Le 30/06/2017 à 09:18, Dmitry A. Kazakov a écrit :
>> Encoding must be a part of the string type. This is essential for
>> dealing with OS/API bindings. E.g. an UTF-8 string must provide a view
>> of an array of octets (for OS/API calls) and a view of an array of code
>> points (for the application). The second view must constitute a class.
>> We don't need explicit conversions between string types.
>>
> This is your opinion. I don't see why it must constitute a class.

Because there is no reason to have exponentially exploding number of 
To_XXX_String functions. Semantically all strings are chains of code points.

> I tend
> to use the simplest structure available for my need, hence avoid tagged
> types unless they are the most appropriate structure.

A type need not to be tagged in order to have a class. Different string 
types have different representations anyway. There is no sense to put a 
tag in there, that will not make view conversion work. The tag will be 
in the String'Class only.

> Moreover, encodings are useful only at the boundary between the
> application and the external world, internal processing should use the
> internal form, i.e. characters (characters are the abstract notion to
> which a code point is associated). Therefore, conversions at the
> boundary seem quite appropriate

True, however for performance reasons many applications tend to deal 
with UTF-8 octets rather than with code points. I doubt anybody uses 
characters at all.

>> But the point is that the language should not have string types at all.
>> The type system should be capable to define things as described above at
>> the library level.
> Then you should be happy. There is absolutely no magic about String in
> Ada (as opposed to most other languages), and string types ARE simply
> defined in a package (namely Standard). They are known to the compiler
> only for attributes that return a string type.

The magic is called array. You have to use magic spell "type ... is 
array (...) of ..." with severe limitation coming with.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de