Re: Ada Idioms Progress Preview

["Marin David Condic" <dont.bother.mcondic.auntie.spam@[acm.org>]

This works nicely so long as you are doing one of two things (again, by
convention.) If you are always allocating your strings off the stack after
deciding how much space you need by entering a new scope or you are always
allocating your strings off the heap with the "new" operator. Both cases
allow you to write string handling code that takes advantage of 'First,
'Last, 'Length and so on.

However, this is not always convenient or simple. Certainly, understanding
the idioms necessary to do it is maybe just a bit beyond the beginner. (Hey,
there's a topic for the Idiom Guys!) Also, it is not something that is
assumed by all of the language supplied services. (Text_IO, being a problem
in this area. Suppose that a Get_Line were to return an access to a string
instead of putting characters into your own string and giving you a length?
That would have its own pitfalls, but it would allow you to structure
everything else using 'First 'Last & 'Length.)

Maybe Ada0x should attempt to establish some convention here? Ahhhhhh....
Skip it! We've got Unbounded strings - just use them!. :-)

MDC
--
Marin David Condic
Senior Software Engineer
Pace Micro Technology Americas    www.pacemicro.com
Enabling the digital revolution
e-Mail:    marin.condic@pacemicro.com
Web:      http://www.mcondic.com/


"Ted Dennison" <dennison@telepath.com> wrote in message
news:zVXd7.109$2u.23585@www.newsranger.com...
> It frees you from that problem in *some* cases. I find that most of the
time I
> don't change the string, so I can declare it perfectly sized. When you do
that,
> you are not storing the length explicitly, but rather implicitly in the
array
> bounds. As others have mentioned, you also don't have to iterate through
every
> valid data element to derive this piece of implicit information like you
do with
> C. Thus perfectly-sized Ada strings give you the best of both worlds.
>
> Unfortunately, the most notable exception to this is in reading data from
> Text_IO, which is also one of the first things a newbie will want to do
with Ada
> strings. :-(
>