Re: Help Me Please :)

[Robert Dewar <robert_dewar@my-deja.com>]

In article <38BC4EAF.209AE20C@port.ac.uk>,
  Will Mann <csm90231@port.ac.uk> wrote:
> Can some one help me with my Ada.. my lecturer has given me
code that
> doesn't work... the compiler says that it can't handle
"A".."Z" the
> error message is :
>
>  Inappropriate operands for "DOT_DOT" operation, continuing

Well here is how you might be able to find that out for
yourself. Obviously the compiler does not like the operands
for your .. expression, so look up in your Ada book the rules
for .. and you will find that discrete types are required.
Now look up discrete types, and you will find that they
include integer and enumeration types, including particular
character types. Clearly you are trying for the latter here,
so go look up what character literals should look like, and
you will find that they use single quotes, so you should
have written

   'a' .. 'z'

I think you might have had an easier type finding the error
for yourself with GNAT:

g.adb:3:17: expected a discrete type
g.adb:3:17: found a string type

In general I think the error messages from GNAT are likely to
be clearer for a beginner (or anyone else for that matter),
since huge effort has gone into making the messages clear.
You might consider getting hold of a copy of GNAT (which is
available for free download -- go to the ftp directories
at cs.nyu.edu, directory /pub/gnat).

At the very least, if you get another message you don't
understand, you can try and see what GNAT says :-)

Robert Dewar
Ada Core Technologies


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