Re: Ada Idioms Progress Preview

[Ole-Hjalmar Kristensen <ohk@clustra.com>]

lutz@iks-jena.de (Lutz Donnerhacke) writes:

> * Ole-Hjalmar Kristensen wrote:
> >One thing which can be said in favour of having a terminator character is
> >that it frees you from having to store the length explicitly.
> 
> This requires an out-of-band terminator, which does not exists in C.
> Instead they prefer to use a valid character they do not need at the moment.
> 
> But the real problem of a terminator character is creating a view:
> In order to reference a substring you have to create a full copy of the
> substring because you have to insert the terminal character. Inserting it
> directly into the main version would cause serve damage.
> 
> Dealing with copies:
>   - is time inefficient.
>   - is semantical different modulo modifications.
>   - is space inefficient.
>   - requires heap space instead of stack space.
> 
> >The length of a string is usually different from the size of the array
> >used to store the string.
> 
> It's not necessary to provide a buffer to hold any possible string of a
> given type if you can pass complex objects to or from a function. C can only
> pass primitive types and therefore switched to passing pointers of implicit
> terminated arrays.

Close, but not quite. C will happily pass records by value.

-- 
Kabelsalat ist gesund.

Ole-Hj. Kristensen