Re: string literals

Re: string literals

[Robert Dewar]

"but don't want to use [the package with character literals]"

why on earth not? this is what use is for! There is a certain style of
Ada question that goes like:

   How do I do X without using Y

where Y is exactly the feature intended to support X. Most odd!

If you are worried that the use clause would clutter up the name space, a
nice way of doing things is to put the definition of the character type 
into a nested package:

   package Stuff is
      ...
      package Char_Type_Package is
         type Char_Type is ( ....
      end Char_Type_Package;
   end Stuff;

now you can just say use Stuff.Char_Type_Package and you have access to the
literals.

Re: string literals

[Pascal OBRY]

Cary Jamison wrote :

>but I can't find a way to do anything like
>
>  My_String : Pkg1.Big_String(1..5) := Pkg1."Hello";
>
>other than (Pkg1.'H', Pkg1.'e', ...)

Well with Ada9x you can use a single type without do a use of the full
package.

	see use type (RM 8.4)

You should be able to write :

	use type Pkg1.Big_Char;

	My_String : Pkg1.Big_String(1..5) := "Hello";
	

I think this address your problem.

Pascal.
--

--|---------------------------------------------------------------
--| Pascal OBRY			e-mail: pascal.obry@der.edf.fr   |
--| EDF-DER-IPN-SID-ISI					         |
--| Bureau G1-010			voice: +33-1-47.65.50.91 |
--| 1 Av General de Gaulle				         |
--| 92141 Clamart CEDEX		     			         |
--| FRANCE			     			         |
--|---------------------------------------------------------------

Re: string literals

[Robert Dewar]

An absolute rule against all use clauses is misconceived and ill-advised,
but you can live with it, because the consequence is just junky hard to
read source code, and tools can hide the junk from you.

An absolute rule against all use of unchecked conversion is true folly. There
are all sorts of situations in which UC is an important tool, and completely
forbidding its use seriously cripples the language.

Sure it can be misused, so can addition and integers, but that doesn't mean
you should ban addition and integers.

Indeed the requirement of an explicit with of unchecked conversion is
precisely intended to allow *control* of the use of this important feature,
not its *elimination*.

I can't tell you how many times I have seen people decide that you can't do
something in Ada, and therefore resort to C, or whatever, just because they
have crippled Ada with silly restrictions.

Re: string literals

[Richard G. Hash]

In <3fbtgk$501@gnat.cs.nyu.edu> dewar@cs.nyu.edu (Robert Dewar) writes:
>
> Also, Keith says that it is as hard to look at a variable and know where
> it came from as [...]
> 
> Nonsense, the first question can be answered by a trivial tool, you should
> indeed be able to click on an identifier and have a window pop up with
> the declaration. [...]

Since this tool will be so "trivial", I hope you plan on including
it in the GNAT effort. Can we expect it by, oh, say, next month?

1/2 ;-)

--
Richard G. Hash                                      email: rgh@shell.com
Shell Development Company, Bellaire Research Center  phone: (713) 245-7311
Member Team Ada                Free Ada95 compilers: cs.nyu.edu:/pub/gnat

Re: string literals

[Robert Dewar]

"Since this tool will be so "trivial", I hope you plan on including
it in the GNAT effort. Can we expect it by, oh, say, next month?"

certainly not by next month, but I would hope this would happen soon. 
Tools for GNAT have to be mostly fashioned outside NYU, since NYU (and
the GNAT contract) are concentrated on the compiler itself. However,
I do expect various interesting things to be happening in the tool
department, stay tuned!

Re: string literals

[Rolf Ebert]

>>>>> "Richard" == Richard G Hash <rgh@shell.com> writes:

Richard> In <3fbtgk$501@gnat.cs.nyu.edu> dewar@cs.nyu.edu (Robert Dewar)
Richard> writes:
>>  Also, Keith says that it is as hard to look at a variable and know
>> where it came from as [...]
>> 
>> Nonsense, the first question can be answered by a trivial tool, you
>> should indeed be able to click on an identifier and have a window pop
>> up with the declaration. [...]

Richard> Since this tool will be so "trivial", I hope you plan on
Richard> including it in the GNAT effort. Can we expect it by, oh, say,
Richard> next month?

Richard> 1/2 ;-)

It's already there! 

Try Emacs with the latest Ada Mode on cs.nyu.edu:/pub/gnat.  It contains
a support mode for the gnat Xreferencer GNATF.  Click with the mouse on
an identifier, Emacs will place your cursor at its declaration. The tool
knows everthing about overloading, record fields, etc.

The current release 2.12 of the Ada Mode has a problem, if the xref
information is not immidiately available (i.e. must be regenerated). 
This will be fixed in the upcoming 2.13.

Richard> -- Richard G. Hash email: rgh@shell.com Shell Development
Richard> Company, Bellaire Research Center phone: (713) 245-7311 Member
Richard> Team Ada Free Ada95 compilers: cs.nyu.edu:/pub/gnat

	Rolf


--
Rolf Ebert                      Beratung fuer Energiesysteme und Informatik
Erich Kaestner Str. 17               Conseil en Energetique et Informatique
D - 80796 Muenchen        (Team Ada)               Tel.: +49-89-30.77.88.00
Germany                                            Fax.: +49-89-30.77.91.00