Re: Bounded String question

[Serge Robyns <serge.robyns@gmail.com>]

Hi Bob,

On Wednesday, 11 November 2015 01:48:43 UTC+1, Bob Duff  wrote:
> How about:
> 
>    function No_Client_Name return T_Client_Name is
>       (T_Client_Name (P_Strings.Null_Bounded_String));

May idea was to have a "constant" and use language construct/semantic to expose that.  I was expecting that the compiler will have more optimization options with such a construct than a dynamic construct like above.
 
> But why do you need Preelaborate?  It's not all that much use if you use
> GNAT's static elaboration model.

Just for the sake of "cleanness" and again using language features to express my intent as per my "expectations".  Even if I would end up using GNAT in all cases.

> > Maybe I'm using bounded strings completely wrong.
> 
> Well, I think the Ada.Strings.Bounded package is way overengineered.
> So "using Ada.Strings.Bounded" = "using bounded strings wrong".  ;-)
> I suggest rolling your own.  No need for generics.
> 
>    type Bounded_String (Max_Length : Natural := ...) is limited record
>       Length : Natural := 0;
>       Chars  : String (1 .. Max_Length);
>    end record;
> 
> along with a few trivial operations.

I tend to agree that the bounded strings seems over-engineered but I'm lacking Ada experience to judge that properly.  However it is indeed a pain to use compared to other languages where I come from, e.g. C.  I don't know why strings are so complex to use in Ada. At various places I've conversions between bounded strings and plain strings in order to offer a consistent API to my modules. Luckily the package already provide a To_String function.  However, I've had to write loads of functions like "To_Client_Name (Name : in String) return T_Client_Name is (T_Client_Name (P_Strings.To_Bounded_String (Name));" as I haven't found a more direct way to convert a string to the type. This with some other oddities in Ada is what do give me a lot of frustrations.  However, I do remain decided to proceed with Ada, as I do believe in its core principles of allowing developing reliable software.

Now with regards to rolling my own, is this not defeating re-use?  Why shall I waste my time on such a feature while I'm having loads of things to do on the application itself.

I've been considering using unbounded strings instead but then I'm dropping the idea of a bounded storage for my entities.  Most of these "strings" ends up in record types which in the end will map to database entities.

> - Bob

Serge