Re: Text parsing package

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

On Mon, 28 Mar 2011 12:18:38 +0200, Yannick Duch�ne (Hibou57) wrote:

> Le Mon, 28 Mar 2011 10:15:52 +0200, Dmitry A. Kazakov  
> <mailbox@dmitry-kazakov.de> a �crit:
>>>> 3. As others have mentioned, it is a good idea to abstract the source
>>>> formats in order to be able to parse files, strings, streams etc.
>>> And Ada already provides a root for that: Ada.Streams.Root_Stream_Type
>>
>> Unfortunately Root_Stream_Type is not an interface and string cannot be
>> inherited from. So in the effect you would need a special root.
> I meant implementing a concrete Root_Stream_Type using a string as source.  
> You would have an open method, getting a string or any kind of reference  
> to string, just not as a filename this time. But wonder about efficiency  
> (because of the tagged type), which is important for such low-level and  
> heavily iterated stuff.

Another problem is that it would be difficult to use. Mix-in does not work
because String cannot be a discriminant. You would have a nasty
access-to-string one or have to copy the whole string into the stream
object.

>> Yes, it would be nice to have structured multiple co-routines as an
>> alternative to FSM. There are some cases where tasks look like an  
>> overkill.
> I remember I made that wish too (can't remember what was said to advocate  
> against it).

The reason is always same, if there is nobody from ARG personally
interested in the concept, it will be blindly rejected. Here I mean not the
implementation, but merely a serious consideration of possible ways to
approach the problem. Alone this require much mental work.

> Let's hope for Ada 2017 or Ada 2022.

I doubt it. This is a "serious" issue, not a patch or yet another kludge.

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