Ada extension information

Ada extension information

[info]

Hello,
a-textio.adb released with GNAT 2009 GPL for windows, contains:

Item :=
              (if not Is_Start_Of_Encoding (Character'Val (ch),
File.WC_Method)
               then Character'Val (ch)
               else Get_Upper_Half_Char_Immed (Character'Val (ch),
File));

which is easy enough to understand but is not standard Ada.

GNAT 2009 tells me :

try.adb:5:09: conditional expression is an Ada extension
try.adb:5:09: use -gnatX switch to compile this unit

http://www.adacore.com/2009/03/29/NF-63-I317-009-gnat/ discusses
this.

Is it not jumping the gun a little to use these extensions to document
standard libraries before they become official, or even documented?

More specifically where are these Ada extensions formally documented?
(Ada Conformity Assessment Authority seem to have discussion about
this up to 15th March 2009 !)

PS In the meantime Mika is broken if you use a-textio as distributed
with GNAT GPL  2009.

Sincerely,
http://www.midoan.com

Re: Ada extension information

[Martin]

On May 28, 7:26 pm, i...@midoan.com wrote:
> Hello,
> a-textio.adb released with GNAT 2009 GPL for windows, contains:
>
> Item :=
>               (if not Is_Start_Of_Encoding (Character'Val (ch),
> File.WC_Method)
>                then Character'Val (ch)
>                else Get_Upper_Half_Char_Immed (Character'Val (ch),
> File));
>
> which is easy enough to understand but is not standard Ada.
>
> GNAT 2009 tells me :
>
> try.adb:5:09: conditional expression is an Ada extension
> try.adb:5:09: use -gnatX switch to compile this unit
>
> http://www.adacore.com/2009/03/29/NF-63-I317-009-gnat/discusses
> this.
>
> Is it not jumping the gun a little to use these extensions to document
> standard libraries before they become official, or even documented?

Probably not, as there is nothing I know of requires the standard
libraries to be written in Ada, let alone 'vanilla' Ada.

Even if it was in the public part of the specification I guess it
would still be ok if used for something 'implementation-defined'.

Cheers
-- Martin

Re: Ada extension information

[Georg Bauhaus]

info@midoan.com wrote:

> More specifically where are these Ada extensions formally documented?

This is AI 147, Conditional Expressions (as primaries).
http://www.ada-auth.org/cgi-bin/cvsweb.cgi/ai05s/ai05-0147-1.txt?rev=1.2

Yet another thing that makes Ada more attractive
for programmers who would not waste valuable time
for finding names, say write a small named function
that conditionally returs this or that.
Obviously, local functions are overly verbose
and explicative, they must be avoided at all cost.

Ada finally gets C's  ?:  conditionals!
Have you ever seen anyone using ?: in C or Perl in
a way that is obfuscating? Really?

Nah, it's nice!  We can even leave out the bulky
comb structure.  Just pairs of parentheses!
the Lisp fans will rejoyce, C programmers will
feel at home, done with a single stroke!

loop
   exit if (if N > 0 then M/N > 0 else M > 1);
   N := F(M, N);
end loop;

Not even Lisp or ML style let bindings are necessary!
Ah, fancy that! We've got more and more anonymous pointers,
free and easy,  why not free floating control structure
then?  I forget, it's a nice opportunity for tool vendors
to sell more style enforcment programs and language restriction
options.  They are learning ... :-)

Re: Ada extension information

[Georg Bauhaus]

Georg Bauhaus wrote:

The first signs of confusion have already made it
into this example ;-)

> loop
>    exit if (if N > 0 then M/N > 0 else M > 1);
   exit when (if N > 0 then M/N > 0 else M > 1);
>    N := F(M, N);
> end loop;

Re: Ada extension information

[Adam Beneschan]

On May 28, 2:22 pm, Georg Bauhaus <rm.tsoh.plus-
bug.bauh...@maps.futureapps.de> wrote:
> i...@midoan.com wrote:
> > More specifically where are these Ada extensions formally documented?
>
> This is AI 147, Conditional Expressions (as primaries).http://www.ada-auth.org/cgi-bin/cvsweb.cgi/ai05s/ai05-0147-1.txt?rev=1.2
>
> Yet another thing that makes Ada more attractive
> for programmers who would not waste valuable time
> for finding names, say write a small named function
> that conditionally returs this or that.
> Obviously, local functions are overly verbose
> and explicative, they must be avoided at all cost.
>
> Ada finally gets C's  ?:  conditionals!
> Have you ever seen anyone using ?: in C or Perl in
> a way that is obfuscating? Really?
>
> Nah, it's nice!  We can even leave out the bulky
> comb structure.  Just pairs of parentheses!
> the Lisp fans will rejoyce, C programmers will
> feel at home, done with a single stroke!
>
> loop
>    exit if (if N > 0 then M/N > 0 else M > 1);
>    N := F(M, N);
> end loop;
>
> Not even Lisp or ML style let bindings are necessary!
> Ah, fancy that! We've got more and more anonymous pointers,
> free and easy,  why not free floating control structure
> then?  I forget, it's a nice opportunity for tool vendors
> to sell more style enforcment programs and language restriction
> options.  They are learning ... :-)

Hey, it's not part of the Ada language yet, so no need to get all
worked up.  This feature could still be rejected.

And yes, this is certainly a feature that could be abused.  But as the
AI makes clear, there are cases where it can improve readability
because there's no other good way to accomplish the same thing.  Sure,
there are programmers who don't understand readability who would use
this construct in an inappropriate place, just because the feature is
there.  But those programmers probably wouldn't write readable code no
matter how many features you took away from them.  I've seen plenty of
incomprehensible Ada 83 code so I'm sure this is true.

                                       -- Adam

Re: Ada extension information

[Randy Brukardt]

"Martin" <martin.dowie@btopenworld.com> wrote in message 
news:0d9fe71d-788c-46b0-8c5b-18bd229d7246@r3g2000vbp.googlegroups.com...
...
>> Is it not jumping the gun a little to use these extensions to document
>> standard libraries before they become official, or even documented?
>
>Probably not, as there is nothing I know of requires the standard
>libraries to be written in Ada, let alone 'vanilla' Ada.
>
>Even if it was in the public part of the specification I guess it
>would still be ok if used for something 'implementation-defined'.

That is correct. There is no requirement that Ada standard packages be 
implemented in Ada (although generally the standard tries to make that 
possible). I think it is unusual if all of the standard packages *are* 
implemented in Ada.

For instance, Janus/Ada has a couple of units implemented in assembler, and 
there are also a number of standard packages that are 'built-in'; that is 
there is no implementation at all (the compiler just generates the needed 
code).

Obviously, portability is enhanced if units don't depend on 
compiler-specific features, but that hardly matters for the language-defined 
units. No one is going to try to compile the Janus/Ada Ada.Text_IO package 
with GNAT (or vice versa) -- both compilers have their own!

                             Randy.

Re: Ada extension information

[anon]

The problem is, those extra routines that make use of the "C like conditional 
compiling statements" are define in the body and referenced in the private 
sections of "Ada.Text_IO" and "Ada.Wide_Text_IO" packages. The comments 
state that they are for a sub-package "Ada.Text_IO.Wide_Text_IO" that is not 
present in the source. In scanning all 2850 plus files in the 2009 GNAT, the 
only references to this sub-package is in comments from the following 3 files:

  Ada.Text_IO 
  Ada.Wide_Text_IO
and 
  System.WCh_WtS

So, why are these routines in the two Text IO packages, and where is that 
child package "Ada.Text_IO.Wide_Text_IO"?  

Now, if these routines are defined and reference only with-in the package 
they are defined, then why are these routines references in the specification 
private area, they should be at the top of the body, hidden from the 
specification side. Keeping the Ada Text packages more precise to the Ada 
language, instead of junking it up with references that are not used outside 
ofthat package.   

Or is this somewhat of an advance copy of 2010/2011 version of 
Ada.Text_IO and a new "Ada.Text_IO.Wide_Text_IO" package.


And there is no reference in the documentation of the "C like conditional 
compiling statements".

From RM 1.1.3 "Conformity of an Implementation with the Standard" 

    6  Contain no variations except those explicitly permitted by this
       International Standard, or those that are impossible or
       impractical to avoid given the implementation's execution
       environment;

    7  Specify all such variations in the manner prescribed by this
       International Standard.


No True Ada programmer wants "Language extensions" without references.  
And most would prefer some simple references that is stated with-in the RM, 
not just hinted to by the RM, like having a RM section on what type 
"conditional compiling statements" would be acceptable with a few examples. 

So where is the documentation that is requred by RM 1.1.3 ( 7 ). Plus, 
I have not found where "conditional compiling statements" are allow 
in Ada RM 1.1.3 ( 6 ). And in some cases "conditional compiling 
statements" kills the need for generic package.

Plus, there is another Adacore pragma ( sample located in body of 
Ada.Sequential_IO ). This seams to bypass the requirement to use 
"-gnatX". 

      pragma Extensions_Allowed ( On | Off ) ;

with no documentation in the GNAT Documentation User's Guide ( GNAT_UGN ) 
or the GNAT Reference Manual ( GNAT_RM ).

Plus, if Adacore want to extend Ada, they normally use a child package 
with-in the GNAT package structure to test the idea before forcing the 
changes into the the Ada package structure. 

And finally what other changes have been made and how to disable them. Aka 
to turn off all "conditional expressions"? And for that reason the "C like 
conditional compiling statements" should never be in the core Ada or core 
System packages that are define in the RM.




In <d784432e-fa9d-4bc9-b849-ecb2208afc73@c9g2000yqm.googlegroups.com>, info@midoan.com writes:
>Hello,
>a-textio.adb released with GNAT 2009 GPL for windows, contains:
>
>Item :=
>              (if not Is_Start_Of_Encoding (Character'Val (ch),
>File.WC_Method)
>               then Character'Val (ch)
>               else Get_Upper_Half_Char_Immed (Character'Val (ch),
>File));
>
>which is easy enough to understand but is not standard Ada.
>
>GNAT 2009 tells me :
>
>try.adb:5:09: conditional expression is an Ada extension
>try.adb:5:09: use -gnatX switch to compile this unit
>
>http://www.adacore.com/2009/03/29/NF-63-I317-009-gnat/ discusses
>this.
>
>Is it not jumping the gun a little to use these extensions to document
>standard libraries before they become official, or even documented?
>
>More specifically where are these Ada extensions formally documented?
>(Ada Conformity Assessment Authority seem to have discussion about
>this up to 15th March 2009 !)
>
>PS In the meantime Mika is broken if you use a-textio as distributed
>with GNAT GPL  2009.
>
>Sincerely,
>http://www.midoan.com

Re: Ada extension information

[info]

On May 30, 8:13 am, a...@anon.org (anon) wrote:
> The problem is, those extra routines that make use of the "C like conditional
> compiling statements" are define in the body and referenced in the private
> sections of "Ada.Text_IO" and "Ada.Wide_Text_IO" packages. The comments
> state that they are for a sub-package "Ada.Text_IO.Wide_Text_IO" that is not
> present in the source. In scanning all 2850 plus files in the 2009 GNAT, the
> only references to this sub-package is in comments from the following 3 files:
>
>   Ada.Text_IO
>   Ada.Wide_Text_IO
> and
>   System.WCh_WtS
>
> So, why are these routines in the two Text IO packages, and where is that
> child package "Ada.Text_IO.Wide_Text_IO"?  
>
> Now, if these routines are defined and reference only with-in the package
> they are defined, then why are these routines references in the specification
> private area, they should be at the top of the body, hidden from the
> specification side. Keeping the Ada Text packages more precise to the Ada
> language, instead of junking it up with references that are not used outside
> ofthat package.  
>
> Or is this somewhat of an advance copy of 2010/2011 version of
> Ada.Text_IO and a new "Ada.Text_IO.Wide_Text_IO" package.
>
> And there is no reference in the documentation of the "C like conditional
> compiling statements".
>
> From RM 1.1.3 "Conformity of an Implementation with the Standard"
>
>     6  Contain no variations except those explicitly permitted by this
>        International Standard, or those that are impossible or
>        impractical to avoid given the implementation's execution
>        environment;
>
>     7  Specify all such variations in the manner prescribed by this
>        International Standard.
>
> No True Ada programmer wants "Language extensions" without references.  
> And most would prefer some simple references that is stated with-in the RM,
> not just hinted to by the RM, like having a RM section on what type
> "conditional compiling statements" would be acceptable with a few examples.
>
> So where is the documentation that is requred by RM 1.1.3 ( 7 ). Plus,
> I have not found where "conditional compiling statements" are allow
> in Ada RM 1.1.3 ( 6 ). And in some cases "conditional compiling
> statements" kills the need for generic package.
>
> Plus, there is another Adacore pragma ( sample located in body of
> Ada.Sequential_IO ). This seams to bypass the requirement to use
> "-gnatX".
>
>       pragma Extensions_Allowed ( On | Off ) ;
>
> with no documentation in the GNAT Documentation User's Guide ( GNAT_UGN )
> or the GNAT Reference Manual ( GNAT_RM ).
>
> Plus, if Adacore want to extend Ada, they normally use a child package
> with-in the GNAT package structure to test the idea before forcing the
> changes into the the Ada package structure.
>
> And finally what other changes have been made and how to disable them. Aka
> to turn off all "conditional expressions"? And for that reason the "C like
> conditional compiling statements" should never be in the core Ada or core
> System packages that are define in the RM.
>
> In <d784432e-fa9d-4bc9-b849-ecb2208af...@c9g2000yqm.googlegroups.com>, i...@midoan.com writes:
> >Hello,
> >a-textio.adb released with GNAT 2009 GPL for windows, contains:
>
> >Item :=
> >              (if not Is_Start_Of_Encoding (Character'Val (ch),
> >File.WC_Method)
> >               then Character'Val (ch)
> >               else Get_Upper_Half_Char_Immed (Character'Val (ch),
> >File));
>
> >which is easy enough to understand but is not standard Ada.
>
> >GNAT 2009 tells me :
>
> >try.adb:5:09: conditional expression is an Ada extension
> >try.adb:5:09: use -gnatX switch to compile this unit
>
> >http://www.adacore.com/2009/03/29/NF-63-I317-009-gnat/discusses
> >this.
>
> >Is it not jumping the gun a little to use these extensions to document
> >standard libraries before they become official, or even documented?
>
> >More specifically where are these Ada extensions formally documented?
> >(Ada Conformity Assessment Authority seem to have discussion about
> >this up to 15th March 2009 !)
>
> >PS In the meantime Mika is broken if you use a-textio as distributed
> >with GNAT GPL  2009.
>
> >Sincerely,
> >http://www.midoan.com
>
>

Just to clarify what Mika, our test data generator, uniquely it
appears, does. During test data generation, and only if the user's
code uses standrad libraries, Mika analyses the standard libraries and
uses that information to simulate their behaviour. We believe that
this approach is more accurate, repeatable and thorough than other
alternatives such as writing manual stubs for them. It also offers the
possibility of generating more interesting tests that cover the CFG of
the standard libraries (not to test the standard libraries, but rather
to generate tests that are borderline and that may not be expected by
the developers).


It therefore makes our job easier if the libraries are written in
standard Ada. The fact that they are close to it is already a great
help for us: althought we cannot analyse everything, things left in
code during development (but would probably be removed in the final
version) such as usages of textio do not have to removed; the code
does not have to be modified.

We released a minor update yesterday, and Mika can now parse
conditional expressions in standard libraries.

Regards,
Midoan