[26210] in Perl-Users-Digest
Perl-Users Digest, Issue: 8396 Volume: 10
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Thu Sep 8 09:05:27 2005
Date: Thu, 8 Sep 2005 06:05:06 -0700 (PDT)
From: Perl-Users Digest <Perl-Users-Request@ruby.OCE.ORST.EDU>
To: Perl-Users@ruby.OCE.ORST.EDU (Perl-Users Digest)
Perl-Users Digest Thu, 8 Sep 2005 Volume: 10 Number: 8396
Today's topics:
<> and filehandles in hashes <BZ@caradhras.net>
Re: <> and filehandles in hashes <zen13097@zen.co.uk>
Re: application question <sisyphus1@nomail.afraid.org>
Re: application question <"h.v.niekerk at hccnet.nl">
Re: application question <john@castleamber.com>
Crude Email Adddress CHecking <uctraing@ultranet.com>
Re: Crude Email Adddress CHecking <steve@uptime.org.uk>
Re: Launching And Detaching <someone@example.com>
Re: Launching And Detaching axel@white-eagle.invalid.uk
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: 8 Sep 2005 11:13:03 GMT
From: BZ <BZ@caradhras.net>
Subject: <> and filehandles in hashes
Message-Id: <slrndi075v.mfv.BZ@kalypso.caradhras.net>
Hi!
Can anyone please explain to me why this code doesn't work? (it gives
a syntax error on the "print while..." line):
---- snip ----
#!/usr/bin/perl
use strict;
use warnings;
my %rec;
$rec{filename} = '/etc/fstab';
open($rec{fh},$rec{filename}) or die("$! while opening");
my @arr;
push @arr, { %rec };
# next line results in a syntax error:
print while (<$arr[0]->{fh}>);
close($rec{fh}) or die("$! while closing");
---- snip ----
If I change the <$arr[0]->{fh}> to readline($arr[0]->{fh}), it works
fine, and it also works fine if I put the filehandle in a scalar
variable first:
## this works fine again
my @arr;
push @arr, { %rec };
my $fh = $arr[0]->{fh};
print while (<$fh>);
Does anyone have a clue what's going on here?
--
BZ
------------------------------
Date: 08 Sep 2005 11:31:13 GMT
From: Dave Weaver <zen13097@zen.co.uk>
Subject: Re: <> and filehandles in hashes
Message-Id: <43202101$0$306$da0feed9@news.zen.co.uk>
On 8 Sep 2005 11:13:03 GMT, BZ <BZ@caradhras.net> wrote:
...
> If I change the <$arr[0]->{fh}> to readline($arr[0]->{fh}), it works
> fine, and it also works fine if I put the filehandle in a scalar
> variable first:
>
> ## this works fine again
> my @arr;
> push @arr, { %rec };
> my $fh = $arr[0]->{fh};
> print while (<$fh>);
>
> Does anyone have a clue what's going on here?
Taken from `perldoc perlop`:
If what the angle brackets contain is a simple scalar variable
(e.g., <$foo>), then that variable contains the name of the
filehandle to input from, or its typeglob, or a reference to the
same. For example:
$fh = \*STDIN;
$line = <$fh>;
If what's within the angle brackets is neither a filehandle nor a
simple scalar variable containing a filehandle name, typeglob,
or typeglob reference, it is interpreted as a filename pattern to
be globbed, and either a list of filenames or the next filename
in the list is returned, depending on context.
------------------------------
Date: Thu, 8 Sep 2005 14:25:11 +1000
From: "Sisyphus" <sisyphus1@nomail.afraid.org>
Subject: Re: application question
Message-Id: <431fbd61$0$8993$afc38c87@news.optusnet.com.au>
"Huub" <"h.v.niekerk at hccnet.nl"> wrote in message
news:431fb6a5$0$769$3a628fcd@reader10.nntp.hccnet.nl...
> Hi,
>
> I have to do a project that will combine computergraphics, AI and
> scripting. I know perl can be used for AI and scripting, but how about
> graphics (e.g. OpenGL)? I read the faq, but couldn't find an answer on
that.
>
As regards OpenGL see:
http://search.cpan.org/search?query=OpenGL&mode=module
Note also that PDL (Perl Data Language) can be built with OpenGL and PGPLOT
support.
For perl graphics in general see:
http://search.cpan.org/modlist/Graphics
Cheers,
Rob
------------------------------
Date: Thu, 08 Sep 2005 06:59:06 +0200
From: Huub <"h.v.niekerk at hccnet.nl">
Subject: Re: application question
Message-Id: <431fc471$0$777$3a628fcd@reader20.nntp.hccnet.nl>
Sisyphus wrote:
> "Huub" <"h.v.niekerk at hccnet.nl"> wrote in message
> news:431fb6a5$0$769$3a628fcd@reader10.nntp.hccnet.nl...
>
>>Hi,
>>
>>I have to do a project that will combine computergraphics, AI and
>>scripting. I know perl can be used for AI and scripting, but how about
>>graphics (e.g. OpenGL)? I read the faq, but couldn't find an answer on
>
> that.
>
>
> As regards OpenGL see:
> http://search.cpan.org/search?query=OpenGL&mode=module
>
> Note also that PDL (Perl Data Language) can be built with OpenGL and PGPLOT
> support.
>
> For perl graphics in general see:
> http://search.cpan.org/modlist/Graphics
>
> Cheers,
> Rob
>
>
Thank you.
------------------------------
Date: 8 Sep 2005 05:01:21 GMT
From: John Bokma <john@castleamber.com>
Subject: Re: application question
Message-Id: <Xns96CBCBDA4Bcastleamber@130.133.1.4>
Huub <"h.v.niekerk at hccnet.nl"> wrote:
> Hi,
>
> I have to do a project that will combine computergraphics, AI and
> scripting. I know perl can be used for AI and scripting, but how about
> graphics (e.g. OpenGL)? I read the faq, but couldn't find an answer on
> that.
http://search.cpan.org/search?query=opengl&mode=all
--
John Small Perl scripts: http://johnbokma.com/perl/
Perl programmer available: http://castleamber.com/
Happy Customers: http://castleamber.com/testimonials.html
------------------------------
Date: Thu, 08 Sep 2005 12:08:41 GMT
From: Bob <uctraing@ultranet.com>
Subject: Crude Email Adddress CHecking
Message-Id: <20a0i1ti70jr65hg767f49tfaid762m2kf@4ax.com>
OK, admitting up front that I know it's impossible to actually check
email addresses for validity due to the possible valid address
formats...
I'm looking for a routine/chunk of code that will check email
addresses for compliance with fairly standard formats i.e. it
needs to be user@somedomain.com format, contain no spaces, etc.
Anyone have a chunk or a pointer?
Thanks,
Bob (barely a perl programmer :-)
------------------------------
Date: Thu, 08 Sep 2005 13:15:57 +0100
From: Stephen Hildrey <steve@uptime.org.uk>
Subject: Re: Crude Email Adddress CHecking
Message-Id: <1126181757.32143.0@eunomia.uk.clara.net>
Bob wrote:
> OK, admitting up front that I know it's impossible to actually check
> email addresses for validity due to the possible valid address
> formats...
>
> I'm looking for a routine/chunk of code that will check email
> addresses for compliance with fairly standard formats i.e. it
> needs to be user@somedomain.com format, contain no spaces, etc.
perldoc -q "valid mail"
Steve
--
Stephen Hildrey
E-mail: steve@uptime.org.uk / Tel: +442071931337
Jabber: steve@jabber.earth.li / MSN: foo@hotmail.co.uk
------------------------------
Date: Thu, 08 Sep 2005 05:02:22 GMT
From: "John W. Krahn" <someone@example.com>
Subject: Re: Launching And Detaching
Message-Id: <yBPTe.166396$wr.106988@clgrps12>
Hal Vaughan wrote:
> I'm using one simple program to launch some daemons. When I launch a
> program, I use backticks. (This is all on Linux, in bash, btw.) I've
> added "2>&1 >/dev/null &" to the command line, so it's like this:
>
> `/path/to/program 2>&1 >/dev/null &`;
>
> I've noticed that if I include the '&' so the program detaches from the
> shell, if I kill the launching program, the child process survives. I've
> also tried this by forking first:
>
> if (!fork()) {
> `/path/to/program 2>&1 >/dev/null &`;
> exit;
> }
>
> I had the hope that if I forked and launched like this, once all the
> programs were launched, the launching program would exit. It doesn't. Is
> there a way I can launch a program, then have the first program exit, so
> it's no longer using that bash instance (without killing it)?
Just putting '&' at the end does not detach a process from the shell.
man nohup
perldoc perlipc
John
--
use Perl;
program
fulfillment
------------------------------
Date: Thu, 08 Sep 2005 11:27:34 GMT
From: axel@white-eagle.invalid.uk
Subject: Re: Launching And Detaching
Message-Id: <GeVTe.6644$k22.3228@fe2.news.blueyonder.co.uk>
Hal Vaughan <hal@thresholddigital.com> wrote:
> I'm using one simple program to launch some daemons. When I launch a
> program, I use backticks. (This is all on Linux, in bash, btw.) I've
> added "2>&1 >/dev/null &" to the command line, so it's like this:
>
> `/path/to/program 2>&1 >/dev/null &`;
>
> I've noticed that if I include the '&' so the program detaches from the
> shell, if I kill the launching program, the child process survives. I've
> also tried this by forking first:
>
> if (!fork()) {
> `/path/to/program 2>&1 >/dev/null &`;
> exit;
> }
>
> I had the hope that if I forked and launched like this, once all the
> programs were launched, the launching program would exit. It doesn't. Is
> there a way I can launch a program, then have the first program exit, so
> it's no longer using that bash instance (without killing it)?
You should not been using backticks for this purpose - they
are designed to collect data from the external program
and will wait for that program.
Have a look at: perldoc -f exec
Axel
------------------------------
Date: 6 Apr 2001 21:33:47 GMT (Last modified)
From: Perl-Users-Request@ruby.oce.orst.edu (Perl-Users-Digest Admin)
Subject: Digest Administrivia (Last modified: 6 Apr 01)
Message-Id: <null>
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------------------------------
End of Perl-Users Digest V10 Issue 8396
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