How do I use GNAT.Directory_Operations.Iteration?

How do I use GNAT.Directory_Operations.Iteration?

[Kulin Remailer]

I need to navigate through a directory structure. It seems like
GNAT.Directory_Operations.Iteration would help but I don't know how to use
it. I guess it should be instantiated as a generic but I don't understand
what syntax to use. Decorum prevents me from posting my futile attempts to
do that!  Can anyone explain how I should instantiate and use it?

Re: How do I use GNAT.Directory_Operations.Iteration?

[Thomas Løcke]

On 2011-03-14 19:18, Kulin Remailer wrote:
> I need to navigate through a directory structure. It seems like
> GNAT.Directory_Operations.Iteration would help but I don't know how to use
> it. I guess it should be instantiated as a generic but I don't understand
> what syntax to use. Decorum prevents me from posting my futile attempts to
> do that!  Can anyone explain how I should instantiate and use it?


http://wiki.ada-dk.org/index.php/Ada.Directories#Directory_Searching

That should get you started.

:o)

-- 
Thomas L�cke

Email: tl at ada-dk.org
Web: http//:ada-dk.org
http://identi.ca/thomaslocke

Re: How do I use GNAT.Directory_Operations.Iteration?

[Dmitry A. Kazakov]

On 14 Mar 2011 18:18:35 -0000, Kulin Remailer wrote:

> I need to navigate through a directory structure.

http://rosettacode.org/wiki/Walk_Directory_Tree#Ada

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de

Re: How do I use GNAT.Directory_Operations.Iteration?

[Stephen Leake]

Kulin Remailer <remailer@reece.net.au> writes:

> I need to navigate through a directory structure. It seems like
> GNAT.Directory_Operations.Iteration would help but I don't know how to use
> it. I guess it should be instantiated as a generic but I don't understand
> what syntax to use. Decorum prevents me from posting my futile attempts to
> do that!  Can anyone explain how I should instantiate and use it?

It would be better to post your futile attempts. This accomplishes two
things:

1) convince us you are actually trying (yes, sometimes we get paranoid
   about freeloaders)

2) show us where you are going wrong, so we can give targeted help

-- 
-- Stephe

Re: How do I use GNAT.Directory_Operations.Iteration?

[Dmitry A. Kazakov]

On Tue, 15 Mar 2011 02:30:20 -0400, Stephen Leake wrote:

> 2) show us where you are going wrong, so we can give targeted help

I would try to guess. It is possibly the flaw in the Ada.Directories
design, that the directory tree [or graph] is not properly abstracted. One
should manually filter out ".", ".." and other OS-dependent entities
breaking the abstraction.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de

Re: How do I use GNAT.Directory_Operations.Iteration?

[Nomen Nescio]

Hi everyone, thanks for your examples. My problem is instantiating the
GNAT.Directory_Operations.Iteration package and all of your answers are
about using Ada.Directories in code, which is not what I am asking about.

I may use your examples instead of the GNAT package because it would be more
portable, but I would like to understand how to instantiate the GNAT
package. I cannot figure the right syntax.

Thank you.

Re: How do I use GNAT.Directory_Operations.Iteration?

[Ludovic Brenta]

Nomen Nescio wrote on comp.lang.ada:
> Hi everyone, thanks for your examples. My problem is instantiating the
> GNAT.Directory_Operations.Iteration package and all of your answers are
> about using Ada.Directories in code, which is not what I am asking about.
>
> I may use your examples instead of the GNAT package because it would be more
> portable, but I would like to understand how to instantiate the GNAT
> package. I cannot figure the right syntax.

Something like:

   procedure Do_Something_With (Item : String; Index : Positive;
Quit : in out Boolean);
   -- processes the file named Item.  Implementation left to the
reader.

   procedure Do_Something_On_All_Files_Matching is
     new GNAT.Directory_Operations.Iteration.Find (Action =>
Do_Something_With);
begin
   Do_Something_On_All_Files_Matching (Root_Directory => "/",
File_Pattern => ".*\.ad[bs]");

HTH

--
Ludovic Brenta.

Re: How do I use GNAT.Directory_Operations.Iteration?

[Nasser M. Abbasi]

On 3/15/2011 3:23 AM, Ludovic Brenta wrote:
> Nomen Nescio wrote on comp.lang.ada:
>> Hi everyone, thanks for your examples. My problem is instantiating the
>> GNAT.Directory_Operations.Iteration package and all of your answers are
>> about using Ada.Directories in code, which is not what I am asking about.
>>
>> I may use your examples instead of the GNAT package because it would be more
>> portable, but I would like to understand how to instantiate the GNAT
>> package. I cannot figure the right syntax.
>
> Something like:
>
>     procedure Do_Something_With (Item : String; Index : Positive;
> Quit : in out Boolean);
>     -- processes the file named Item.  Implementation left to the
> reader.
>
>     procedure Do_Something_On_All_Files_Matching is
>       new GNAT.Directory_Operations.Iteration.Find (Action =>
> Do_Something_With);
> begin
>     Do_Something_On_All_Files_Matching (Root_Directory =>  "/",
> File_Pattern =>  ".*\.ad[bs]");
>
> HTH
>
> --
> Ludovic Brenta.

When I also looked at the documentation for these packages, I could not
find any examples on how to use these:

http://www.iuma.ulpgc.es/users/jmiranda/gnat-rts/rts/g-dirope__ads.htm

When I write something myself, I try to always put a small example
at the top, as part of it documentation, of how to call or use it.
It would be nice if these had such examples.


--Nasser

Re: How do I use GNAT.Directory_Operations.Iteration?

[Simon Wright]

"Nasser M. Abbasi" <nma@12000.org> writes:

> On 3/15/2011 3:23 AM, Ludovic Brenta wrote:
>> Nomen Nescio wrote on comp.lang.ada:
>>> Hi everyone, thanks for your examples. My problem is instantiating
>>> the GNAT.Directory_Operations.Iteration package and all of your
>>> answers are about using Ada.Directories in code, which is not what I
>>> am asking about.
>>>
>>> I may use your examples instead of the GNAT package because it would
>>> be more portable, but I would like to understand how to instantiate
>>> the GNAT package. I cannot figure the right syntax.
>>
>> Something like:
>>
>>     procedure Do_Something_With (Item : String; Index : Positive;
>> Quit : in out Boolean);
>>     -- processes the file named Item.  Implementation left to the
>> reader.
>>
>>     procedure Do_Something_On_All_Files_Matching is
>>       new GNAT.Directory_Operations.Iteration.Find (Action =>
>> Do_Something_With);
>> begin
>>     Do_Something_On_All_Files_Matching (Root_Directory =>  "/",
>> File_Pattern =>  ".*\.ad[bs]");
>>
>> HTH
>>
>> --
>> Ludovic Brenta.
>
> When I also looked at the documentation for these packages, I could not
> find any examples on how to use these:
>
> http://www.iuma.ulpgc.es/users/jmiranda/gnat-rts/rts/g-dirope__ads.htm

The actual documentation is at
http://gcc.gnu.org/onlinedocs/gcc-4.5.0/gnat_rm/GNAT_002eDirectory_005fOperations_002eIteration-_0028g_002ddiopit_002eads_0029.html#GNAT_002eDirectory_005fOperations_002eIteration-_0028g_002ddiopit_002eads_0029
(gosh, what a URL! might be better to start here:
http://gcc.gnu.org/onlinedocs/gcc-4.5.0/gnat_rm/The-GNAT-Library.html#The-GNAT-Library
and look for g-diopit.ads)

and it's not helpful (specially to a newcomer).

There's a discussion of the use of generic formal subprograms at
http://en.wikibooks.org/wiki/Ada_Programming/Generics#Generic_formal_subprograms

> When I write something myself, I try to always put a small example
> at the top, as part of it documentation, of how to call or use it.
> It would be nice if these had such examples.

Agreed, to some extent. Though it'd only really be helpful here if you'd
never come across generic formal subprograms before. The comments in the
spec (the secret GNAT documentation!) seem pretty explicit, aside only
from the language detail that the OP had trouble with.

Re: How do I use GNAT.Directory_Operations.Iteration?

[Nasser M. Abbasi]

On 3/15/2011 4:15 AM, Simon Wright wrote:

>
> The actual documentation is at
> http://gcc.gnu.org/onlinedocs/gcc-4.5.0/gnat_rm/GNAT_002eDirectory_005fOperations_002eIteration-_0028g_002
>ddiopit_002eads_0029.html#GNAT_002eDirectory_005fOperations_002eIteration-_0028g_002ddiopit_002eads_0029
> (gosh, what a URL! might be better to start here:
> http://gcc.gnu.org/onlinedocs/gcc-4.5.0/gnat_rm/The-GNAT-Library.html#The-GNAT-Library
> and look for g-diopit.ads)
>

Yes, I know about those, and have visited them, but they do not have the source code?
All what it says:

"9.56 GNAT.Directory_Operations.Iteration (g-diopit.ads)

A child unit of GNAT.Directory_Operations providing additional
operations for iterating through directories."

But how to use it? The same link for the gcc part, I looked at also.
I was looking for the source code, to get an idea how to call it.

> and it's not helpful (specially to a newcomer).
>
> There's a discussion of the use of generic formal subprograms at
> http://en.wikibooks.org/wiki/Ada_Programming/Generics#Generic_formal_subprograms
>

>> When I write something myself, I try to always put a small example
>> at the top, as part of it documentation, of how to call or use it.
>> It would be nice if these had such examples.
>
> Agreed, to some extent. Though it'd only really be helpful here if you'd
> never come across generic formal subprograms before. The comments in the
> spec (the secret GNAT documentation!) seem pretty explicit, aside only
> from the language detail that the OP had trouble with.

Well, considering that Ada is used very little relatively speaking,
then one can say that almost all programmers can be classified as Ada
newbies.

So, having documentation readily available on how to call or use something
will make it easier for the rest of use to start using Ada, else a newbie
can get frustrated and drop it.

Many of us learn better by seeing examples, I know I do.

--Nasser

Re: How do I use GNAT.Directory_Operations.Iteration?

[Kulin Remailer]

example snipped

> > --
> > Ludovic Brenta.

Thanks Ludovic! I didn't see your post because like all responsible netizens
I killfile all google groups. Thanks to Nasser for quoting you.

> When I write something myself, I try to always put a small example
> at the top, as part of it documentation, of how to call or use it.
> It would be nice if these had such examples.

Thanks Nasser. I agree it would be nice if the GNAT doc would give examples
of using each API. The package spec is often enough but not always enough.

Re: How do I use GNAT.Directory_Operations.Iteration?

[Kulin Remailer]

> > http://www.iuma.ulpgc.es/users/jmiranda/gnat-rts/rts/g-dirope__ads.htm

Thank you.

> There's a discussion of the use of generic formal subprograms at
> http://en.wikibooks.org/wiki/Ada_Programming/Generics#Generic_formal_subprograms 

Thank you.

> Agreed, to some extent. Though it'd only really be helpful here if you'd
> never come across generic formal subprograms before. The comments in the
> spec (the secret GNAT documentation!) seem pretty explicit, aside only
> from the language detail that the OP had trouble with.

Well I have instantiated generics for text io, enumeration io etc but this
iteration generic threw me for a loop (pun intended!) Maybe it was the
double indirection. First you have to define a procedure and then
instantiate the generic with your procedure. I guess I have only understood
how a type is given to instantiate a generic, not a procedure.

The package spec does explain how to use the API as far as I can see, not
having tried it yet. The issue for me is not knowing Ada enough.

Re: How do I use GNAT.Directory_Operations.Iteration?

[Adam Beneschan]

On Mar 15, 10:20 am, Kulin Remailer <remai...@reece.net.au> wrote:
>
> Thanks Ludovic! I didn't see your post because like all responsible netizens
> I killfile all google groups. Thanks to Nasser for quoting you.

I don't know about anyone else, but... if I asked a group of people
for advice on, say, fishing, and then covered my ears if the person
who responded came from a country I had a beef with or belonged to a
political party I don't like---I'd think that would be incredibly rude
behavior.  This strikes me as similar.  Asking a group for advice, and
then shutting out a certain subset of that group who may provide good
advice, seems like poor etiquette, unfriendly, something like that, I
dunno...

Unfortunately, or maybe fortunately, the OP won't see this because I'm
in the group of people he's killfiled.  Maybe this isn't as big a deal
as I'm making out of it, but it's really rubbing me the wrong way.

                            -- Adam

Re: How do I use GNAT.Directory_Operations.Iteration?

[Ludovic Brenta]

Adam Beneschan <adam@irvine.com> writes:
> On Mar 15, 10:20 am, Kulin Remailer <remai...@reece.net.au> wrote:
>>
>> Thanks Ludovic! I didn't see your post because like all responsible netizens
>> I killfile all google groups. Thanks to Nasser for quoting you.
>
> I don't know about anyone else, but... if I asked a group of people
> for advice on, say, fishing, and then covered my ears if the person
> who responded came from a country I had a beef with or belonged to a
> political party I don't like---I'd think that would be incredibly rude
> behavior.  This strikes me as similar.  Asking a group for advice, and
> then shutting out a certain subset of that group who may provide good
> advice, seems like poor etiquette, unfriendly, something like that, I
> dunno...
>
> Unfortunately, or maybe fortunately, the OP won't see this because I'm
> in the group of people he's killfiled.  Maybe this isn't as big a deal
> as I'm making out of it, but it's really rubbing me the wrong way.

This is not a Google Group, it is Usenet comp.lang.ada; Google Groups is
only one of a large number of Usenet clients allowing access to it.  I
think the OP simply doesn't know that (and therefore is an uneducated
netizen).  But his attitude might say something about the signal to
noise ratio in other Google Groups :)

-- 
Ludovic Brenta.

Re: How do I use GNAT.Directory_Operations.Iteration?

[Noel Duffy]

On Tue, 15 Mar 2011 14:40:39 -0700, Adam Beneschan wrote:

> Asking a group for advice, and then shutting out a certain subset
> of that group who may provide good advice, seems like poor
> etiquette, unfriendly, something like that, I dunno...

Lots of people feel compelled to do this because of the enormous
volume of spam that originates from Google Groups. Google have ignored
the problem for years and do not seem to care about Usenet at all. If
your ISP, like most in NZ, does not do NNTP any more, there are lots
of free Usenet servers that you can use, so there is no need to read
or post through Google Groups unless you are feeling especially
masochistic. I am using eternal-september.org who are pretty good at
filtering out the vast majority of the crap so the only filtering I do
is for posts cross-posted to two or more groups.

Of course, as with any filtering, there is a risk that you will get
false positives, and reading comp.lang.ada while filtering out the
posts of Ludovic is a doozy of a false positive!

Re: How do I use GNAT.Directory_Operations.Iteration?

[Anonymous]

Ludovic Brenta <ludovic@ludovic-brenta.org> wrote:

> > I don't know about anyone else, but... if I asked a group of people
> > for advice on, say, fishing, and then covered my ears if the person
> > who responded came from a country I had a beef with or belonged to a
> > political party I don't like---I'd think that would be incredibly rude
> > behavior. This strikes me as similar.

It's not similar. I didn't filter on the group after I posted to it, I have
been filtering on google groups for a long time to eliminate spam. Your
analogy isn't. I figure anybody intelligent enough to participate in usenet
is intelligent enough to post through a news server or m2n gateway and use a
news client and that's conventional wisdom.

> Asking a group for advice, and then shutting out a certain subset of that
> group who may provide good advice, seems like poor etiquette, unfriendly,
> something like that, I dunno...

That's right, you don't know. It's standard practice to eliminate certain
news servers because of spam and people who think usenet is google groups
and use it as their playground. I realize there are two or three legitimate
posters on google groups and I would like to see what they have to say but
the spam and millions of noise level posts make that not worth it in the
long run. What gives you the right to tell me what I have to read?

> > Unfortunately, or maybe fortunately, the OP won't see this because I'm
> > in the group of people he's killfiled.  Maybe this isn't as big a deal
> > as I'm making out of it, but it's really rubbing me the wrong way.

You're going to be rubbed a lot more that way if you stay on usenet because
many people are killfiling google (and other) usenet gateway posts.

> This is not a Google Group, it is Usenet comp.lang.ada; Google Groups is
> only one of a large number of Usenet clients allowing access to it.  I
> think the OP simply doesn't know that (and therefore is an uneducated
> netizen).  

Now Ludovic, what ever gave you that idea? I'm posting through Mix and I use
a news client and I never go anywhere near google or google groups. I think
I understand very well what usenet is and is not. ;)

> But his attitude might say something about the signal to noise ratio in
> other Google Groups :) 

It's not an attitude, it's simply a sensible approach to spam and noise
reduction in usenet.

And to the whiner who's post you copied, I have every right to choose what
forums to read, what newspapers to read, etc. If you find that offensive
you're on your own.

Re: How do I use GNAT.Directory_Operations.Iteration?

[Simon Wright]

Anonymous <nobody@remailer.paranoici.org> writes:

> And to the whiner who's post you copied, I have every right to choose
> what forums to read, what newspapers to read, etc. If you find that
> offensive you're on your own.

Given that attitude, I think I should killfile anything from 'remailer'.

Re: How do I use GNAT.Directory_Operations.Iteration?

[Kulin Remailer]

Here's just *one* answer for Shrill Bill:

http://twovoyagers.com/improve-usenet.org/

Re: How do I use GNAT.Directory_Operations.Iteration?

[Ludovic Brenta]

Anonymous wrote on comp.lang.ada:
> Ludovic Brenta <ludo...@ludovic-brenta.org> wrote:
>>> I don't know about anyone else, but... if I asked a group of people
>>> for advice on, say, fishing, and then covered my ears if the person
>>> who responded came from a country I had a beef with or belonged to a
>>> political party I don't like---I'd think that would be incredibly rude
>>> behavior. This strikes me as similar.
>
> It's not similar. I didn't filter on the group after I posted to it, I have
> been filtering on google groups for a long time to eliminate spam. Your
> analogy isn't. I figure anybody intelligent enough to participate in usenet
> is intelligent enough to post through a news server or m2n gateway and use a
> news client and that's conventional wisdom.

There are places where firewalls block NNTP.  Mail to news does not
always work either.  In these situations, the only reasonable option
is a web interface to Usenet.

>> Asking a group for advice, and then shutting out a certain subset of that
>> group who may provide good advice, seems like poor etiquette, unfriendly,
>> something like that, I dunno...
>
> That's right, you don't know.

Adam doesn't know that Google Groups is a source of a lot of spam,
simply because comp.lang.ada is mostly spam-free, even with all those
"evil" Google Groupers as regulars.  Which is what *you* seem not to
know.  Personally, I think Adam overreacted to your overreaction.

> It's standard practice to eliminate certain news servers
       ^^^^^^^^^^^^^^^^^

It's "standard practice" to program in Visual Basic or Java, not Ada.
So don't get me started on "standard practices".

> because of spam and people who think usenet is google groups
> and use it as their playground. I realize there are two or three legitimate
> posters on google groups and I would like to see what they have to say but
> the spam and millions of noise level posts make that not worth it in the
> long run. What gives you the right to tell me what I have to read?

Adam is an expert on Ada. If you want to learn Ada then you should
listen to him, no matter what news client he chooses.  And if you're
going to make friends on this place, you'd better not antagonize
people a priori.

'nuff said and read, I'll now ignore the rest of this thread.

--
Ludovic Brenta.

Re: How do I use GNAT.Directory_Operations.Iteration?

[Mart van de Wege]

Simon Wright <simon@pushface.org> writes:

> Anonymous <nobody@remailer.paranoici.org> writes:
>
>> And to the whiner who's post you copied, I have every right to choose
>> what forums to read, what newspapers to read, etc. If you find that
>> offensive you're on your own.
>
> Given that attitude, I think I should killfile anything from 'remailer'.

Funny thing. I have a global down-score rule on anything coming through
dizum.com, as my experience is that mostly trolls use anonymizers.

For some reason, someone posting through dizum complaining about Google
Groups accounts being mostly spammers appears to me to be a splendid
case of stones and glass houses.

And that's the last thing I'll say in this off-topic conversation.

Mart

-- 
"We will need a longer wall when the revolution comes."
    --- AJS, quoting an uncertain source.

Re: How do I use GNAT.Directory_Operations.Iteration?

[Kulin Remailer]

> Funny thing. I have a global down-score rule on anything coming through
> dizum.com, as my experience is that mostly trolls use anonymizers.

I don't agree but you're entitled to your opinion just as I am mine.

> For some reason, someone posting through dizum complaining about Google
> Groups accounts being mostly spammers appears to me to be a splendid
> case of stones and glass houses.

First of all nobody spams through remailers as it's not cost effective. How
surprising people in free software groups are the first to campaign against
free speech. I guess free speech isn't one of your fictitous (insert number
of Freedoms) "freedoms". I'm entitled to post how I please, if you don't
like it you're free to killfile me or ignore me. But I don't see how my
question was off-topic, and I said thanks to people who posted. The silly
personal agenda rants from you and your buddy are the problem, not my
posting. Neither of you actually contributed to the thread, you both just
added noise and discord. We were doing fine without you thanks very much.

Perhaps you should stop trolling and stop accusing other people of things
they haven't done. The only complaints in the thread are coming from you
anti-freedom activists.

Re: How do I use GNAT.Directory_Operations.Iteration?

[Anonymous]

> Yes, I know about those, and have visited them, but they do not have the
> source code? 

What I did was browse to the adainclude lib under the gcc directory for my
Linux distro, for Slackware 64 the path is

/usr/lib64/gcc/x86_64-slackware-linux/4.3.3/adainclude/

And in there I found the package specs and bodies for the API I found in the
top secret Ada manuals (grins at Jeffrey Carter).

> Well, considering that Ada is used very little relatively speaking,
> then one can say that almost all programmers can be classified as Ada
> newbies.

I thought it was just me but I guess I'm not alone!

> So, having documentation readily available on how to call or use something
> will make it easier for the rest of use to start using Ada, else a newbie
> can get frustrated and drop it.

Yes, that's true but this group is very helpful. I didn't post before but I
got a good answer right away. Thanks guys!

> Many of us learn better by seeing examples, I know I do.

Yes, agreed.

Re: How do I use GNAT.Directory_Operations.Iteration?

[Stephen Leake]

Nomen Nescio <nobody@dizum.com> writes:

> Hi everyone, thanks for your examples. My problem is instantiating the
> GNAT.Directory_Operations.Iteration package and all of your answers are
> about using Ada.Directories in code, which is not what I am asking about.
>
> I may use your examples instead of the GNAT package because it would be more
> portable, but I would like to understand how to instantiate the GNAT
> package. I cannot figure the right syntax.

Once again, if you show us what you've tried, we could be more helpful

-- 
-- Stephe