[31007] in Perl-Users-Digest
Perl-Users Digest, Issue: 2252 Volume: 11
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Thu Mar 5 14:09:50 2009
Date: Thu, 5 Mar 2009 11:09:13 -0800 (PST)
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, 5 Mar 2009 Volume: 11 Number: 2252
Today's topics:
A globbing question <yakovlev@hotmail.com>
Re: A globbing question <yakovlev@hotmail.com>
Re: A globbing question <syscjm@sumire.gwu.edu>
Re: A globbing question <someone@example.com>
Re: A globbing question <jimsgibson@gmail.com>
Find Windows Compression attribute? <novastaylor@gmail.com>
Re: Find Windows Compression attribute? QoS@invalid.net
Re: Find Windows Compression attribute? <smallpond@juno.com>
Net::Appliance::Session error? or something else? <scottdware@gmail.com>
Re: Net::Appliance::Session error? or something else? <smallpond@juno.com>
Re: Net::Appliance::Session error? or something else? <scottdware@gmail.com>
Re: Net::Appliance::Session error? or something else? <scottdware@gmail.com>
Strange system() slowdown when using Inline::C <ross.girshick@gmail.com>
Re: Strange system() slowdown when using Inline::C <ross.girshick@gmail.com>
Re: system not returning correct return code. <ben@morrow.me.uk>
use constant and hash <michaelgang@gmail.com>
Re: use constant and hash (Tim McDaniel)
Re: use constant and hash <michaelgang@gmail.com>
Re: What-if algorithm <gamo@telecable.es>
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: Thu, 5 Mar 2009 09:57:36 -0800 (PST)
From: Alex <yakovlev@hotmail.com>
Subject: A globbing question
Message-Id: <4df9f800-2346-459d-8990-48ec66ceee13@b16g2000yqb.googlegroups.com>
Hello,
I'm trying to figure out how to "glob" lists instead of the current
directory. For example:
my @var = File::Glob::bsd_glob('a*');
foreach my $f (@var) {print $f, "\n";}
This fragment will print all the filenames started with 'a' in the
current directory.
I need some function which doesn't depend on the file system. For
example
my @set = ('ab', 'ac', 'bc');
my @var = new_bsd_glob('a*', @set); # <---- non-existing function
with additional parameter
foreach my $f (@var) {print $f, "\n";}
It must work exactly as shell globbing, so it should print 'ab' and
'ac'.
I suspect this "new_bsd_glob" function already exist - could you
please advice where it resides?
Thanks
Alex
------------------------------
Date: Thu, 5 Mar 2009 10:25:04 -0800 (PST)
From: Alex <yakovlev@hotmail.com>
Subject: Re: A globbing question
Message-Id: <1c5733e7-83b1-4d1e-9d51-bb5a87826dbf@s31g2000vbp.googlegroups.com>
On Mar 5, 12:57 pm, Alex <yakov...@hotmail.com> wrote:
> Hello,
>
> I'm trying to figure out how to "glob" lists instead of the current
> directory. For example:
>
> my @var = File::Glob::bsd_glob('a*');
> foreach my $f (@var) {print $f, "\n";}
>
> This fragment will print all the filenames started with 'a' in the
> current directory.
>
> I need some function which doesn't depend on the file system. For
> example
>
> my @set = ('ab', 'ac', 'bc');
> my @var = new_bsd_glob('a*', @set); # <---- non-existing function
> with additional parameter
> foreach my $f (@var) {print $f, "\n";}
>
> It must work exactly as shell globbing, so it should print 'ab' and
> 'ac'.
>
> I suspect this "new_bsd_glob" function already exist - could you
> please advice where it resides?
>
> Thanks
> Alex
I've already found the Text::Glob !!
Thanks
Alex
------------------------------
Date: Thu, 05 Mar 2009 12:25:59 -0600
From: Chris Mattern <syscjm@sumire.gwu.edu>
Subject: Re: A globbing question
Message-Id: <slrngr069n.i9s.syscjm@sumire.gwu.edu>
On 2009-03-05, Alex <yakovlev@hotmail.com> wrote:
> Hello,
>
> I'm trying to figure out how to "glob" lists instead of the current
> directory. For example:
>
> my @var = File::Glob::bsd_glob('a*');
> foreach my $f (@var) {print $f, "\n";}
>
> This fragment will print all the filenames started with 'a' in the
> current directory.
>
> I need some function which doesn't depend on the file system. For
> example
>
> my @set = ('ab', 'ac', 'bc');
> my @var = new_bsd_glob('a*', @set); # <---- non-existing function
> with additional parameter
> foreach my $f (@var) {print $f, "\n";}
>
> It must work exactly as shell globbing, so it should print 'ab' and
> 'ac'.
>
> I suspect this "new_bsd_glob" function already exist - could you
> please advice where it resides?
>
Is there some bizarre reason you can't use regular expressions?
--
Christopher Mattern
NOTICE
Thank you for noticing this new notice
Your noticing it has been noted
And will be reported to the authorities
------------------------------
Date: Thu, 05 Mar 2009 10:31:41 -0800
From: "John W. Krahn" <someone@example.com>
Subject: Re: A globbing question
Message-Id: <iUUrl.24170$Tp5.12225@newsfe13.iad>
Alex wrote:
>
> I'm trying to figure out how to "glob" lists instead of the current
> directory. For example:
>
> my @var = File::Glob::bsd_glob('a*');
> foreach my $f (@var) {print $f, "\n";}
>
> This fragment will print all the filenames started with 'a' in the
> current directory.
>
> I need some function which doesn't depend on the file system. For
> example
>
> my @set = ('ab', 'ac', 'bc');
> my @var = new_bsd_glob('a*', @set); # <---- non-existing function
> with additional parameter
> foreach my $f (@var) {print $f, "\n";}
>
> It must work exactly as shell globbing, so it should print 'ab' and
> 'ac'.
It sounds like you want something like:
my @var = new_bsd_glob('{a*,ab,ac,bc}')
John
--
Those people who think they know everything are a great
annoyance to those of us who do. -- Isaac Asimov
------------------------------
Date: Thu, 05 Mar 2009 10:37:00 -0800
From: Jim Gibson <jimsgibson@gmail.com>
Subject: Re: A globbing question
Message-Id: <050320091037003286%jimsgibson@gmail.com>
In article
<4df9f800-2346-459d-8990-48ec66ceee13@b16g2000yqb.googlegroups.com>,
Alex <yakovlev@hotmail.com> wrote:
> Hello,
>
> I'm trying to figure out how to "glob" lists instead of the current
> directory. For example:
>
> my @var = File::Glob::bsd_glob('a*');
> foreach my $f (@var) {print $f, "\n";}
>
> This fragment will print all the filenames started with 'a' in the
> current directory.
>
> I need some function which doesn't depend on the file system. For
> example
>
> my @set = ('ab', 'ac', 'bc');
> my @var = new_bsd_glob('a*', @set); # <---- non-existing function
> with additional parameter
> foreach my $f (@var) {print $f, "\n";}
>
> It must work exactly as shell globbing, so it should print 'ab' and
> 'ac'.
>
> I suspect this "new_bsd_glob" function already exist - could you
> please advice where it resides?
Perhaps you are looking for grep:
my @var = grep( /a*/, @set );
See 'perldoc -f grep'
--
Jim Gibson
------------------------------
Date: Thu, 5 Mar 2009 05:43:17 -0800 (PST)
From: NovasTaylor <novastaylor@gmail.com>
Subject: Find Windows Compression attribute?
Message-Id: <0baf362e-7b17-4538-8af4-981b109e8c91@x13g2000yqf.googlegroups.com>
Hi folks,
Is there a way I can identify the windows compression property
"Compress contents to save disk space" on files and folders? I have a
large directory structure where I need to find files that have the
compression property active and ideally turn that attribute off.
Simply identifying the files with that attribute would be a good first
step.
Thanks!
Tim
------------------------------
Date: Thu, 05 Mar 2009 15:22:34 GMT
From: QoS@invalid.net
Subject: Re: Find Windows Compression attribute?
Message-Id: <_6Srl.1462$%u5.804@nwrddc01.gnilink.net>
NovasTaylor <novastaylor@gmail.com> wrote in message-id: <0baf362e-7b17-4538-8af4-981b109e8c91@x13g2000yqf.googlegroups.com>
>
> Hi folks,
>
> Is there a way I can identify the windows compression property
> "Compress contents to save disk space" on files and folders? I have a
> large directory structure where I need to find files that have the
> compression property active and ideally turn that attribute off.
> Simply identifying the files with that attribute would be a good first
> step.
>
> Thanks!
>
> Tim
parse the output of compact /s
the third column of the output displays the compression ratio.
example output: 63344 : 63344 = 1.0 to 1 CDILLA05.DLL
------------------------------
Date: Thu, 5 Mar 2009 08:12:48 -0800 (PST)
From: smallpond <smallpond@juno.com>
Subject: Re: Find Windows Compression attribute?
Message-Id: <996ef43c-10fe-41c8-8f79-fd69fe7264e0@t7g2000yqa.googlegroups.com>
On Mar 5, 8:43=A0am, NovasTaylor <novastay...@gmail.com> wrote:
> Hi folks,
>
> Is there a way I can identify the windows compression property
> "Compress contents to save disk space" on files and folders? I have a
> large directory structure where I need to find files that have the
> compression property active and ideally turn that attribute off.
> Simply identifying the files with that attribute would be a good first
> step.
>
> Thanks!
>
> Tim
I believe that you can get this from Win32::File
------------------------------
Date: Thu, 5 Mar 2009 07:36:28 -0800 (PST)
From: scottdware <scottdware@gmail.com>
Subject: Net::Appliance::Session error? or something else?
Message-Id: <fdadc296-c385-4add-8b98-822653ee15f3@d2g2000pra.googlegroups.com>
Hello,
I am having trouble on some of my SSH scripts that are using the
Net::Appliance::Session module on a Unix (Solaris 9) box.
Basically, I keep getting the error:
"Login failed to remote host at line..."
"Pattern match time-out"
Can you see any reason as to why I am getting that? If I use this on
Cygwin, it works fine, but I don't know why it wouldn't work on Unix?
Here's a test script:
#!/usr/local/bin/perl
use strict;
use warnings;
use Net::Appliance::Session;
my $user = "username";
my $pass = "password";
my $host = "somehost.domain.com";
my $command = "show ip int brie";
my $ssh = Net::Appliance::Session->new(Host => $host, Transport =>
'SSH');
eval {
$ssh->connect(Name => $user, Password => $pass, SHKC => 0);
$ssh->cmd(String => $command, Timeout => 30);
sleep 2;
};
if (UNIVERSAL::isa($@, 'Net::Appliance::Session::Exception')) {
print $@->message ."\n";
print $@->lastline ."\n";
print $@->errmsg ."\n";
}
------------------------------
Date: Thu, 5 Mar 2009 08:35:37 -0800 (PST)
From: smallpond <smallpond@juno.com>
Subject: Re: Net::Appliance::Session error? or something else?
Message-Id: <910e9460-72b8-48d8-8071-dab72a555605@s20g2000yqh.googlegroups.com>
On Mar 5, 10:36=A0am, scottdware <scottdw...@gmail.com> wrote:
> Hello,
>
> I am having trouble on some of my SSH scripts that are using the
> Net::Appliance::Session module on a Unix (Solaris 9) box.
>
> Basically, I keep getting the error:
>
> "Login failed to remote host at line..."
> "Pattern match time-out"
>
> Can you see any reason as to why I am getting that? If I use this on
> Cygwin, it works fine, but I don't know why it wouldn't work on Unix?
>
> Here's a test script:
>
> #!/usr/local/bin/perl
>
> use strict;
> use warnings;
> use Net::Appliance::Session;
>
> my $user =3D "username";
> my $pass =3D "password";
> my $host =3D "somehost.domain.com";
> my $command =3D "show ip int brie";
>
> my $ssh =3D Net::Appliance::Session->new(Host =3D> $host, Transport =3D>
> 'SSH');
>
> eval {
> =A0 =A0 =A0 =A0 $ssh->connect(Name =3D> $user, Password =3D> $pass, SHKC =
=3D> 0);
> =A0 =A0 =A0 =A0 $ssh->cmd(String =3D> $command, Timeout =3D> 30);
> =A0 =A0 =A0 =A0 sleep 2;
>
> };
>
> if (UNIVERSAL::isa($@, 'Net::Appliance::Session::Exception')) {
> =A0 =A0 =A0 =A0 print $@->message ."\n";
> =A0 =A0 =A0 =A0 print $@->lastline ."\n";
> =A0 =A0 =A0 =A0 print $@->errmsg ."\n";
>
>
>
> }
The login prompt is not matching what the module expects.
Read the "Important Notes ..." section of Net::SSH::Expect
documentation.
------------------------------
Date: Thu, 5 Mar 2009 09:43:16 -0800 (PST)
From: scottdware <scottdware@gmail.com>
Subject: Re: Net::Appliance::Session error? or something else?
Message-Id: <06586840-922f-4856-b7b6-658c32703188@v18g2000pro.googlegroups.com>
On Mar 5, 11:35=A0am, smallpond <smallp...@juno.com> wrote:
> On Mar 5, 10:36=A0am, scottdware <scottdw...@gmail.com> wrote:
>
>
>
> > Hello,
>
> > I am having trouble on some of my SSH scripts that are using the
> > Net::Appliance::Session module on a Unix (Solaris 9) box.
>
> > Basically, I keep getting the error:
>
> > "Login failed to remote host at line..."
> > "Pattern match time-out"
>
> > Can you see any reason as to why I am getting that? If I use this on
> > Cygwin, it works fine, but I don't know why it wouldn't work on Unix?
>
> > Here's a test script:
>
> > #!/usr/local/bin/perl
>
> > use strict;
> > use warnings;
> > use Net::Appliance::Session;
>
> > my $user =3D "username";
> > my $pass =3D "password";
> > my $host =3D "somehost.domain.com";
> > my $command =3D "show ip int brie";
>
> > my $ssh =3D Net::Appliance::Session->new(Host =3D> $host, Transport =3D=
>
> > 'SSH');
>
> > eval {
> > =A0 =A0 =A0 =A0 $ssh->connect(Name =3D> $user, Password =3D> $pass, SHK=
C =3D> 0);
> > =A0 =A0 =A0 =A0 $ssh->cmd(String =3D> $command, Timeout =3D> 30);
> > =A0 =A0 =A0 =A0 sleep 2;
>
> > };
>
> > if (UNIVERSAL::isa($@, 'Net::Appliance::Session::Exception')) {
> > =A0 =A0 =A0 =A0 print $@->message ."\n";
> > =A0 =A0 =A0 =A0 print $@->lastline ."\n";
> > =A0 =A0 =A0 =A0 print $@->errmsg ."\n";
>
> > }
>
> The login prompt is not matching what the module expects.
> Read the "Important Notes ..." section of Net::SSH::Expect
> documentation.
Thanks. But why would the Net::SSH::Expect module come in handy here,
since I'm not using it? Does it pull from that as well?
------------------------------
Date: Thu, 5 Mar 2009 10:04:37 -0800 (PST)
From: scottdware <scottdware@gmail.com>
Subject: Re: Net::Appliance::Session error? or something else?
Message-Id: <a91d56c3-9ce4-460f-b455-be4eb90fb7b8@v35g2000pro.googlegroups.com>
On Mar 5, 12:43=A0pm, scottdware <scottdw...@gmail.com> wrote:
> On Mar 5, 11:35=A0am, smallpond <smallp...@juno.com> wrote:
>
>
>
> > On Mar 5, 10:36=A0am, scottdware <scottdw...@gmail.com> wrote:
>
> > > Hello,
>
> > > I am having trouble on some of my SSH scripts that are using the
> > > Net::Appliance::Session module on a Unix (Solaris 9) box.
>
> > > Basically, I keep getting the error:
>
> > > "Login failed to remote host at line..."
> > > "Pattern match time-out"
>
> > > Can you see any reason as to why I am getting that? If I use this on
> > > Cygwin, it works fine, but I don't know why it wouldn't work on Unix?
>
> > > Here's a test script:
>
> > > #!/usr/local/bin/perl
>
> > > use strict;
> > > use warnings;
> > > use Net::Appliance::Session;
>
> > > my $user =3D "username";
> > > my $pass =3D "password";
> > > my $host =3D "somehost.domain.com";
> > > my $command =3D "show ip int brie";
>
> > > my $ssh =3D Net::Appliance::Session->new(Host =3D> $host, Transport =
=3D>
> > > 'SSH');
>
> > > eval {
> > > =A0 =A0 =A0 =A0 $ssh->connect(Name =3D> $user, Password =3D> $pass, S=
HKC =3D> 0);
> > > =A0 =A0 =A0 =A0 $ssh->cmd(String =3D> $command, Timeout =3D> 30);
> > > =A0 =A0 =A0 =A0 sleep 2;
>
> > > };
>
> > > if (UNIVERSAL::isa($@, 'Net::Appliance::Session::Exception')) {
> > > =A0 =A0 =A0 =A0 print $@->message ."\n";
> > > =A0 =A0 =A0 =A0 print $@->lastline ."\n";
> > > =A0 =A0 =A0 =A0 print $@->errmsg ."\n";
>
> > > }
>
> > The login prompt is not matching what the module expects.
> > Read the "Important Notes ..." section of Net::SSH::Expect
> > documentation.
>
> Thanks. But why would the Net::SSH::Expect module come in handy here,
> since I'm not using it? Does it pull from that as well?
Ok, I figured it out. I had to specify the "App" parameter inside of
the connect constructor, and then it worked as intended:
$ssh->connect(Name =3D> $user, Password =3D> $pass, SHKC =3D> 0, App =3D> '=
/
usr/local/bin/ssh');
------------------------------
Date: Thu, 5 Mar 2009 09:15:01 -0800 (PST)
From: rbg <ross.girshick@gmail.com>
Subject: Strange system() slowdown when using Inline::C
Message-Id: <2abccbd9-a06e-4258-a02b-dd70be7c59e0@e5g2000vbe.googlegroups.com>
Before reading the code below, I want to make it clear that this code
is just a *simple reproduction* of a bug I'm seeing in some
computational biology code. So please don't point out things like,
"why are you using system() to run date?!?". :-)
The problem I'm having is that when I make the array foo[] large, the
calls to system() slow down enormously. I'm measuring this problem
using `perl -d:DProf ...`
Test case 1 below is slow, test case 2 is faster. The only difference
is LEN = (1<<26) in test case 1 and LEN = (1<<10) in test case 2. I
welcome any ideas on how to debug this bizarre problem.
Thanks!
Ross
Test case 1:
-------------------------
use Inline C;
use strict;
hello();
sub foo {
for my $i (1..1000) {
system('date > /dev/null');
}
}
foo();
__END__
__C__
#define LEN (1<<26)
static char foo[LEN];
void hello() {
int i;
printf("hello world\n");
for (i = 0; i < LEN; i++) {
foo[i] = 0;
}
}
-------------------------
Test case 2
-------------------------
use Inline C;
use strict;
hello();
sub foo {
for my $i (1..1000) {
system('date > /dev/null');
}
}
foo();
__END__
__C__
#define LEN (1<<10)
static char foo[LEN];
void hello() {
int i;
printf("hello world\n");
for (i = 0; i < LEN; i++) {
foo[i] = 0;
}
}
-------------------------
------------------------------
Date: Thu, 5 Mar 2009 09:24:49 -0800 (PST)
From: rbg <ross.girshick@gmail.com>
Subject: Re: Strange system() slowdown when using Inline::C
Message-Id: <03b91f73-2166-4f6c-af9c-27fa157bbf47@v15g2000yqn.googlegroups.com>
I should include the DProf output for these cases.
Test 1:
Total Elapsed Time = 12.65265 Seconds
User+System Time = 3.202649 Seconds
Exclusive Times
%Time ExclSec CumulS #Calls sec/call Csec/c Name
90.5 2.900 2.900 1 2.9000 2.9000 main::foo
Test 2:
Total Elapsed Time = 4.697635 Seconds
User+System Time = 0.337635 Seconds
Exclusive Times
%Time ExclSec CumulS #Calls sec/call Csec/c Name
77.0 0.260 0.260 1 0.2600 0.2600 main::foo
You can see that in test 2, foo() is roughly 10x faster.
------------------------------
Date: Thu, 5 Mar 2009 13:16:50 +0000
From: Ben Morrow <ben@morrow.me.uk>
Subject: Re: system not returning correct return code.
Message-Id: <2vv486-h22.ln1@osiris.mauzo.dyndns.org>
Quoth Eric Pozharski <whynot@pozharski.name>:
> On 2009-03-04, Xho Jingleheimerschmidt <xhoster@gmail.com> wrote:
> > Eric Pozharski wrote:
> >> On 2009-03-03, Ben Morrow <ben@morrow.me.uk> wrote:
> >>>
> >>> Yes. From the $? entry in perldoc perlvar:
> >>>
> >>> If you have installed a signal handler for "SIGCHLD", the value
> >>> of $? will usually be wrong outside that handler.
> >>>
> >>> On systems that honour "IGNORE" for SIGCHLD, it counts as a signal
> >>> handler. So don't do that.
> >>
> >> I would like that quote to be verified.
> >
> > Which aspect?
>
> "If you have ... that handler."
<snip>
>
> (that seems my english is a way bad still) Did I got that right? The
> perldoc wants to say that even if I'm in B<waitpid> and I get SIGCHLD
> then the I<$?> still would be unset?
No. What the perldoc is saying is
If you have a SIGCHLD handler, then any code *outside* that handler
will not see the correct value for $?.
That is:
#!/usr/bin/perl
# $? is useless here.
$SIG{CHLD} = sub {
# $? is still useless here, because nothing inside this handler
# has set it yet.
waitpid ...; # or something else that sets $?
# $? has the correct value here.
};
# $? is useless again here.
One consequence of this is that if you have $SIG{CHLD} = "IGNORE", $? is
*never* useful, since there is none of your code running inside the
handler.
Ben
------------------------------
Date: Thu, 5 Mar 2009 07:43:55 -0800 (PST)
From: david <michaelgang@gmail.com>
Subject: use constant and hash
Message-Id: <7c8c3ca1-0e61-446f-8149-947d16ff7fb5@o11g2000yql.googlegroups.com>
Hi all,
Is there an option to create a constant hash ?
I tried two snippets
This does not compile:
use strict;
use warnings;
my %hash =(1=>2);
use constant A=>%hash;
print A{1},"\n";
>perl -w a.pl
syntax error at a.pl line 5, near "A{"
syntax error at a.pl line 6, near "A{"
Execution of a.pl aborted due to compilation errors.
and the following does not do the work:
use strict;
use warnings;
my %hash =(1=>2);
use constant A=>\%hash;
print A->{1},"\n";
print A->{2},"\n";
print "why do i print this ?\n"
>perl -w a.pl
Use of uninitialized value in print at a.pl line 6.
2
why do i print this ?
I thought afterwards, that the second snippet has no chance to work.
The hash address remains constant even the values changes :-(.
Has anyone another idea ?
Thanks,
David
------------------------------
Date: Thu, 5 Mar 2009 16:24:07 +0000 (UTC)
From: tmcd@panix.com (Tim McDaniel)
Subject: Re: use constant and hash
Message-Id: <gooub6$f6$1@reader1.panix.com>
In article <7c8c3ca1-0e61-446f-8149-947d16ff7fb5@o11g2000yql.googlegroups.com>,
david <michaelgang@gmail.com> wrote:
>Is there an option to create a constant hash ?
What exactly do you mean?
(1) a fixed set of keys -- that is, you can neither create nor delete
entries?
(2) fixed data -- that is, you can give a value to a given key only
once, but you can create and delete keys?
(3) both fixed keys and fixed data?
(4) Do you mean recursive constant -- if there's a hash in a value, si
it locked too?
(5) Do you want the ability to lock and unlock at will?
A CPAN search for
hash readonly
showed module Readonly. Damian Conway suggests its use in _Perl Best
Practices_, ch 4, in preference to "use constant".
I did a CPAN search for
hash locked
and one hit was Hash::Util, which allows various mixtures of those
possibilities. (Note that lock_keys isn't quite (1): it allows
deleting a key.) It's somewhat more flexible, but I prefer to know
that something is read-only forever.
--
Tim McDaniel, tmcd@panix.com
------------------------------
Date: Thu, 5 Mar 2009 08:58:01 -0800 (PST)
From: david <michaelgang@gmail.com>
Subject: Re: use constant and hash
Message-Id: <f0c72752-1036-488f-be37-555303a2fd34@s28g2000vbp.googlegroups.com>
On Mar 5, 6:24=A0pm, t...@panix.com (Tim McDaniel) wrote:
> In article <7c8c3ca1-0e61-446f-8149-947d16ff7...@o11g2000yql.googlegroups=
.com>,
>
> david =A0<michaelg...@gmail.com> wrote:
> >Is there an option to create a constant hash ?
>
> What exactly do you mean?
> (1) a fixed set of keys -- that is, you can neither create nor delete
> =A0 =A0 entries?
> (2) fixed data -- that is, you can give a value to a given key only
> =A0 =A0 once, but you can create and delete keys?
> (3) both fixed keys and fixed data?
> (4) Do you mean recursive constant -- if there's a hash in a value, si
> =A0 =A0 it locked too?
> (5) Do you want the ability to lock and unlock at will?
>
> A CPAN search for
> =A0 =A0 hash readonly
> showed module Readonly. =A0Damian Conway suggests its use in _Perl Best
> Practices_, ch 4, in preference to "use constant".
>
> I did a CPAN search for
> =A0 =A0 hash locked
> and one hit was Hash::Util, which allows various mixtures of those
> possibilities. =A0(Note that lock_keys isn't quite (1): it allows
> deleting a key.) =A0It's somewhat more flexible, but I prefer to know
> that something is read-only forever.
>
> --
> Tim McDaniel, t...@panix.com
I would prefer option 4 but option 3 is also good. Readonly looks nice
but the last version is from 2004 (does not have to mean anything).
Hash::Util looks very interesting.
Thanks
------------------------------
Date: Thu, 5 Mar 2009 15:23:10 +0100
From: gamo <gamo@telecable.es>
Subject: Re: What-if algorithm
Message-Id: <alpine.LNX.2.00.0903051516010.5542@jvz.es>
On Wed, 4 Mar 2009, gamo wrote:
The question remains open since I suspect that a mathematical
bisection doesn't fit for a goal seek problem. I.e. if max=a
& min=b the bisection method croaks if f(a)*f(b)>0 (It doesn't
garantees the Bolzano's theorem).
f() could be a function with if's max, min, abs, etc. that does
not fit well in a mathematical root-finding schema.
TIA
--
http://www.telecable.es/personales/gamo/
"Was it a car or a cat I saw?"
perl -E 'say 111_111_111**2;'
------------------------------
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