Re: case statement in perl
Paul.G wrote:
Below is an extract from the perl script, the switch/case statement seemed like
a simple solution.
# Mail Program #
operation_CHECKFREEPVS();
print $numPV \n;
# print $FreePV[1] $FreePV[0] $numPV\n;
if ($numPV ne 0 ) {
switch ($numPV) {
case 1 { print $FreePV[0] \n; }
case 2 { print $FreePV[0] $FreePV[1] \n; }
case 3 { print $FreePV[0] $FreePV[1] $FreePV[2] \n; }
}
}
Couldn't you just do that like this:
if ( @FreePV @FreePV = 3 ) {
print join( ' ', @FreePV ), \n;
}
else {
print No PV's available \n;
}
John
--
Any intelligent fool can make things bigger and
more complex... It takes a touch of genius -
and a lot of courage to move in the opposite
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Re: case statement in perl
The example below is just a test, I need to be able to insert multiple values
into a command, those values can be either 1, 2 or upto 5.
Below is closer to the working example, but I will read that document and to
help make a final decision.
# Check Free PV's
operation_CHECKFREEPVS();
$NEWMIRROR = $MIRROR + $numPV;
if ($numPV ne 0 $MIRROR le 5) {
# lvextend
print $numPV $NEWMIRROR $MIRROR\n;
switch ($numPV) {
case 1 { run(/usr/sbin/lvextend -m $NEWMIRROR -s $sourcelv
$FreePV[0]); }
case 2 { run(/usr/sbin/lvextend -m $NEWMIRROR -s $sourcelv $FreePV[0]
$FreePV[1]); }
case 3 { run(/usr/sbin/lvextend -m $NEWMIRROR -s $sourcelv $FreePV[0]
$FreePV[1] $FreePV[2]); }
case 4 { run(/usr/sbin/lvextend -m $NEWMIRROR -s $sourcelv $FreePV[0]
$FreePV[1] $FreePV[2] $FreePV[3]); }
case 5 { run(/usr/sbin/lvextend -m $NEWMIRROR -s $sourcelv $FreePV[0]
$FreePV[1] $FreePV[2] $FreePV[3] $FreePV[4]);
}
}
# lvsync
run(/usr/sbin/lvsync -T $sourcelv);
logprint Successful $NEWMIRROR mirrors \t\t synced;
}
else {
cleanexit (10, FAIL \t\t No Free PV's Available);
}
return 0;
}
From: John W. Krahn jwkr...@shaw.ca
To: Perl Beginners beginners@perl.org
Sent: Wednesday, 1 August 2012 4:58 PM
Subject: Re: case statement in perl
Paul.G wrote:
Below is an extract from the perl script, the switch/case statement seemed
like a simple solution.
# Mail Program #
operation_CHECKFREEPVS();
print $numPV \n;
# print $FreePV[1] $FreePV[0] $numPV\n;
if ($numPV ne 0 ) {
switch ($numPV) {
case 1 { print $FreePV[0] \n; }
case 2 { print $FreePV[0] $FreePV[1] \n; }
case 3 { print $FreePV[0] $FreePV[1] $FreePV[2] \n; }
}
}
Couldn't you just do that like this:
if ( @FreePV @FreePV = 3 ) {
print join( ' ', @FreePV ), \n;
}
else {
print No PV's available \n;
}
John
--
Any intelligent fool can make things bigger and
more complex... It takes a touch of genius -
and a lot of courage to move in the opposite
direction. -- Albert Einstein
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Re: case statement in perl
On Wed, Aug 1, 2012 at 9:08 AM, Paul.G medur...@yahoo.com.au wrote:
The example below is just a test, I need to be able to insert multiple
values into a command, those values can be either 1, 2 or upto 5.
Below is closer to the working example, but I will read that document and
to help make a final decision.
# Check Free PV's
operation_CHECKFREEPVS();
$NEWMIRROR = $MIRROR + $numPV;
if ($numPV ne 0 $MIRROR le 5) {
# lvextend
print $numPV $NEWMIRROR $MIRROR\n;
switch ($numPV) {
case 1 { run(/usr/sbin/lvextend -m $NEWMIRROR -s $sourcelv
$FreePV[0]); }
case 2 { run(/usr/sbin/lvextend -m $NEWMIRROR -s $sourcelv
$FreePV[0] $FreePV[1]); }
case 3 { run(/usr/sbin/lvextend -m $NEWMIRROR -s $sourcelv
$FreePV[0] $FreePV[1] $FreePV[2]); }
case 4 { run(/usr/sbin/lvextend -m $NEWMIRROR -s $sourcelv
$FreePV[0] $FreePV[1] $FreePV[2] $FreePV[3]); }
case 5 { run(/usr/sbin/lvextend -m $NEWMIRROR -s $sourcelv
$FreePV[0] $FreePV[1] $FreePV[2] $FreePV[3] $FreePV[4]);
}
}
# lvsync
run(/usr/sbin/lvsync -T $sourcelv);
logprint Successful $NEWMIRROR mirrors \t\t synced;
}
else {
cleanexit (10, FAIL \t\t No Free PV's Available);
}
return 0;
}
From: John W. Krahn jwkr...@shaw.ca
To: Perl Beginners beginners@perl.org
Sent: Wednesday, 1 August 2012 4:58 PM
Subject: Re: case statement in perl
Paul.G wrote:
Below is an extract from the perl script, the switch/case statement
seemed like a simple solution.
# Mail Program #
operation_CHECKFREEPVS();
print $numPV \n;
# print $FreePV[1] $FreePV[0] $numPV\n;
if ($numPV ne 0 ) {
switch ($numPV) {
case 1 { print $FreePV[0] \n; }
case 2 { print $FreePV[0] $FreePV[1] \n; }
case 3 { print $FreePV[0] $FreePV[1] $FreePV[2] \n; }
}
}
Couldn't you just do that like this:
if ( @FreePV @FreePV = 3 ) {
print join( ' ', @FreePV ), \n;
}
else {
print No PV's available \n;
}
John
--
Any intelligent fool can make things bigger and
more complex... It takes a touch of genius -
and a lot of courage to move in the opposite
direction. -- Albert Einstein
--
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Why make life so hard as John suggested you check for the number of
arguments and as long as it is less then 5 you simply join them with a
space and you are done with a single line...
No matter what you do you will always have to check the variables that you
are going to push out, right now I could very well feed a parameter that
ends in a ; and then do something like *rm -rf /* which could make a
serious mess of your system...
Personally I would suggest checking the command flags if they are valid,
and do not contain any funny characters before even considdering putting
this in a system call or equivalent.
Regards,
Rob
Re: case statement in perl
Paul.G wrote:
The example below is just a test, I need to be able to insert multiple values
into a command, those values can be either 1, 2 or upto 5.
Below is closer to the working example, but I will read that document and to
help make a final decision.
# Check Free PV's
operation_CHECKFREEPVS();
$NEWMIRROR = $MIRROR + $numPV;
if ($numPV ne 0 $MIRROR le 5) {
You are using string comparisons on numerical values which may not work
out the way you intended:
$ perl -le'
for my $MIRROR ( 0, 1, 4, 5, 6, 10, 4000 ) {
print $MIRROR le 5 is , $MIRROR le 5 ? TRUE : FALSE;
}
'
0 le 5 is TRUE
1 le 5 is TRUE
4 le 5 is TRUE
5 le 5 is TRUE
6 le 5 is FALSE
10 le 5 is TRUE
4000 le 5 is TRUE
# lvextend
print $numPV $NEWMIRROR $MIRROR\n;
switch ($numPV) {
case 1 { run(/usr/sbin/lvextend -m $NEWMIRROR -s $sourcelv
$FreePV[0]); }
case 2 { run(/usr/sbin/lvextend -m $NEWMIRROR -s $sourcelv $FreePV[0]
$FreePV[1]); }
case 3 { run(/usr/sbin/lvextend -m $NEWMIRROR -s $sourcelv $FreePV[0]
$FreePV[1] $FreePV[2]); }
case 4 { run(/usr/sbin/lvextend -m $NEWMIRROR -s $sourcelv $FreePV[0]
$FreePV[1] $FreePV[2] $FreePV[3]); }
case 5 { run(/usr/sbin/lvextend -m $NEWMIRROR -s $sourcelv $FreePV[0]
$FreePV[1] $FreePV[2] $FreePV[3] $FreePV[4]);
}
You could do that like this:
if ( @FreePV @FreePV = 5 ) {
run( /usr/sbin/lvextend -m $NEWMIRROR -s $sourcelv @FreePV );
}
}
# lvsync
run(/usr/sbin/lvsync -T $sourcelv);
logprint Successful $NEWMIRROR mirrors \t\t synced;
}
else {
cleanexit (10, FAIL \t\t No Free PV's Available);
}
return 0;
}
John
--
Any intelligent fool can make things bigger and
more complex... It takes a touch of genius -
and a lot of courage to move in the opposite
direction. -- Albert Einstein
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Catalyst model problem- WARNING: No tables found, did you forget to specify db_schema?
Hi All, I am trying to learn Catalyst framework, by following the introduction modules available on CPAN. I am doing this on strawberry perl, on my PC. Also, I am using SQLite and have created myapp.db. While trying to create a model, I get the below error: \strawberry\perl\bin\MyApp\scriptmyapp_create.pl model DB DBIC::Schema MyApp::Schema create=static dbi:SQLite:myapp.db on_connect_do=PRAGMA foreign_keys = ON exists D:\strawberry\perl\bin\MyApp\lib\MyApp\Model exists D:\strawberry\perl\bin\MyApp\t Dumping manual schema for MyApp::Schema to directory D:\strawberry\perl\bin\MyApp\lib ... Schema dump completed. WARNING: No tables found, did you forget to specify db_schema? exists D:\strawberry\perl\bin\MyApp\lib\MyApp\Model\DB.pm --- The instruction says make sure your myapp.db database file is in the application's topmost directory. I tried placing myapp.db in all possible directories but it is not working. I understand this warning is coming from Catalyst::Helper::Model::DBIC::Schema.pm, but I am not able to troubleshoot beyond that. Can someone tell me where am I suppose to keep the myapp.db file? Regards Guru
Re: Catalyst model problem- WARNING: No tables found, did you forget to specify db_schema?
Hi Guys, I found out the issue here:) Apparently, there is a note towards the end of the doc: *NOTE:* Be sure you run the script/myapp_server.pl command from the 'base' directory of your application, not inside the script directory itself or it will not be able to locate the myapp.db database file. You can use a fully qualified or a relative path to locate the database file, but we did not specify that when we ran the model helper earlier. Regards Guru On Wed, Aug 1, 2012 at 7:17 PM, Guruprasad Kulkarni guruprasa...@gmail.comwrote: Hi All, I am trying to learn Catalyst framework, by following the introduction modules available on CPAN. I am doing this on strawberry perl, on my PC. Also, I am using SQLite and have created myapp.db. While trying to create a model, I get the below error: \strawberry\perl\bin\MyApp\scriptmyapp_create.pl model DB DBIC::Schema MyApp::Schema create=static dbi:SQLite:myapp.db on_connect_do=PRAGMA foreign_keys = ON exists D:\strawberry\perl\bin\MyApp\lib\MyApp\Model exists D:\strawberry\perl\bin\MyApp\t Dumping manual schema for MyApp::Schema to directory D:\strawberry\perl\bin\MyApp\lib ... Schema dump completed. WARNING: No tables found, did you forget to specify db_schema? exists D:\strawberry\perl\bin\MyApp\lib\MyApp\Model\DB.pm --- The instruction says make sure your myapp.db database file is in the application's topmost directory. I tried placing myapp.db in all possible directories but it is not working. I understand this warning is coming from Catalyst::Helper::Model::DBIC::Schema.pm, but I am not able to troubleshoot beyond that. Can someone tell me where am I suppose to keep the myapp.db file? Regards Guru
RE: Script to test connecting to Oracle DBs
#!/bin/sh C:/grep/grep.exe -S (SERVICE_NAME = tnsnames.ora service.ora rm -r new.ora echo #!/bin/sh tns_ping.sh C:/cygwin/bin/sed.exe 's/(SERVICE_NAME \=/tnsping.exe /' service.oratns_ping.sh vi tns_ping.sh If you find There is a way to pipe the 2 commands let me know but for now this little shell script works Martin ___ Jogi és Bizalmassági kinyilatkoztatás/Verzicht und Vertraulichkeitanmerkung/Note de déni et de confidentialité Ez az üzenet bizalmas. Ha nem ön az akinek szánva volt, akkor kérjük, hogy jelentse azt nekünk vissza. Semmiféle továbbítása vagy másolatának készítése nem megengedett. Ez az üzenet csak ismeret cserét szolgál és semmiféle jogi alkalmazhatósága sincs. Mivel az electronikus üzenetek könnyen megváltoztathatóak, ezért minket semmi felelöség nem terhelhet ezen üzenet tartalma miatt. Diese Nachricht ist vertraulich. Sollten Sie nicht der vorgesehene Empfaenger sein, so bitten wir hoeflich um eine Mitteilung. Jede unbefugte Weiterleitung oder Fertigung einer Kopie ist unzulaessig. Diese Nachricht dient lediglich dem Austausch von Informationen und entfaltet keine rechtliche Bindungswirkung. Aufgrund der leichten Manipulierbarkeit von E-Mails koennen wir keine Haftung fuer den Inhalt uebernehmen. Ce message est confidentiel et peut être privilégié. Si vous n'êtes pas le destinataire prévu, nous te demandons avec bonté que pour satisfaire informez l'expéditeur. N'importe quelle diffusion non autorisée ou la copie de ceci est interdite. Ce message sert à l'information seulement et n'aura pas n'importe quel effet légalement obligatoire. Étant donné que les email peuvent facilement être sujets à la manipulation, nous ne pouvons accepter aucune responsabilité pour le contenu fourni. Date: Sat, 28 Jul 2012 13:45:18 +1200 Subject: Script to test connecting to Oracle DBs From: newbie01.p...@gmail.com To: beginners@perl.org; dbi-us...@perl.org Hi all, I am looking for a Perl script or something similar that I can use to test connection from a client PC to several databases on a server. Does anyone know of any such script lying around somewhere :(- Currently, am testing connection from a client PC to an Oracle DB using Oracle's sqlplus. All is well and good until I have to test connection to multiple databases on the server. So I am hoping to use a Perl script that I can use which will parse some sort of config file that contains hostname.tns_alias combination and then test connection to the Oracle DB and run a simple SQL like SELECT COUNT(1) from USER_TABLES, if I get an error, that means there is an issue connection to that database, otherwise all is good. At the moment, easiest I can think of using Perl's system command to run sqlplus. Or is it better to look at using DBI? Would be very much appreciated if someone can provide me a simple DBI script to start with if that is the best approach to use. Any suggestion/advice much appreciated. Thanks in advance.
Unexpected token error when providing a regular expression as input
Hi
My program takes is supposed to take regular expression and a file
containing a list of words/lines as input and print all those lines
that match the regular expression. Below is the program
#!/usr/bin/perl
use strict;
use warnings;
sub grep_file {
my $pattern = shift;
my @file_names = @_;
for my $file_name (@file_names) {
open my ($file_handle), $file_name;
while(my $line = $file_handle) {
if ($line =~ m/$pattern/) {
print $line;
}
}
close $file_handle;
}
}
grep_file @ARGV;
When I execute this program from the command line by running ./
grep.pl (.es.){3} /usr/share/dict/words , I get the error
bash: syntax error near unexpected token `.es.'
But, if execute it as ./grep.pl \(.es.\){3} /usr/share/dict/
words , I get the expected result.
Please help me understand this.
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Re: Script to test connecting to Oracle DBs
use strict;
use DBI;
use DBD::Oracle qw(:ora_types);
my $user = '';
my $passwd = '';
my $tnsName = '';
$ENV{'ORACLE_HOME'} = 'C:\oracle\product\10.2.0\client_1';
my $dbh = DBI-connect(dbi:Oracle:$tnsName, $user, $passwd);
my $SQL = qq{ SELECT XXX};
my $sth0 = $dbh-prepare($SQL);
print SQL is prepared;\n;
$sth0-execute();
print SQL is executed;\n;
$sth0-finish();
On Fri, Jul 27, 2012 at 6:45 PM, newbie01 perl newbie01.p...@gmail.com wrote:
Hi all,
I am looking for a Perl script or something similar that I can use to test
connection from a client PC to several databases on a server.
Does anyone know of any such script lying around somewhere :(-
Currently, am testing connection from a client PC to an Oracle DB using
Oracle's sqlplus. All is well and good until I have to test connection to
multiple databases on the server.
So I am hoping to use a Perl script that I can use which will parse some
sort of config file that contains hostname.tns_alias combination and then
test connection to the Oracle DB and run a simple SQL like SELECT COUNT(1)
from USER_TABLES, if I get an error, that means there is an issue
connection to that database, otherwise all is good.
At the moment, easiest I can think of using Perl's system command to run
sqlplus. Or is it better to look at using DBI? Would be very much
appreciated if someone can provide me a simple DBI script to start with if
that is the best approach to use.
Any suggestion/advice much appreciated. Thanks in advance.
--
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Re: case statement in perl
On 08/01/2012 03:08 AM, Paul.G wrote: The example below is just a test, I need to be able to insert multiple values into a command, those values can be either 1, 2 or upto 5. you aren't getting the issue. the switch module was a major mistake and no one should be using it. you have to understand the downside to source filtering. no module can properly filter perl code as it is too subtle and complex to do so automatically. so source filters can seem to work now and if you do some changes to your code (not even near the switch stuff), it could break and you will have a hell of a time fixing it. the downside of that nasty hard to find bug is never worth it even if switch.pm appeals to you. modern perl's have a builtin given/when statement, you can use dispatch tables (especially for a fixed list of numbers or tokens) and other methods too. just avoid using the switch module. there is no way you can defend its use given the extremely nasty possible bugs it can introduce. uri -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: Unexpected token error when providing a regular expression as input
On Tue, Jul 31, 2012 at 12:54 AM, moijes12 moije...@gmail.com wrote:
When I execute this program from the command line by running ./
grep.pl (.es.){3} /usr/share/dict/words , I get the error
bash: syntax error near unexpected token `.es.'
But, if execute it as ./grep.pl \(.es.\){3} /usr/share/dict/
words , I get the expected result.
The parenthesis and curly braces mean something special to the command
line. It's not a Perl issue. It's a shell issue. In your case, the bash
shell. bash tries to interpret (.es.){3} before running Perl. Those
extra slashes you added tell bash to not interpret the parenthesis.
You could also get around the problem by quoting the regular expression on
the command line, like this:
# ./grep.pl '(.es.){3}' /usr/share/dict/words
Hope that helps.
--
Robert Wohlfarth
RE: Cannot connect to Oracle db; script will not run
have a look at
http://search.cpan.org/~pythian/DBD-Oracle-1.46/lib/DBD/Oracle/Troubleshooting.pm
it should answer most of your questions
From: james.war...@acxiom.com
To: beginners@perl.org; dbi-us...@perl.org
CC: newbie01.p...@gmail.com; rob.di...@gmx.com
Subject: Cannot connect to Oracle db; script will not run
Date: Wed, 1 Aug 2012 00:54:13 +
--Beyond some training, I'm very much a newbie to Perl (and this list). So,
please indulge me with my first attempt at a posted question to you; please
see below (*with the full code Perl script toward the bottom of my email)...
-I've been dealing with an issue in a Perl script that I'm writing, similar
to what was posted recently under 'Subject: Script to test connecting to
Oracle DBs' (and 'Subject: Re: Script to test connecting to Oracle DBs' by
Rob Dixon).
Specifically, from my code:
$ENV{TWO_TASK} = lady;
$dbh = DBI-connect($connString, $ladyUser, $ladyPass,
{ AutoCommit=0, RaiseError=0, PrintError=0, ora_check_sql=0 }) or die
Could not connect to database: . DBI-errstr ;
... ...but I still keep getting the same error message at command line in
unix:
naszcard@gustavo: /ou8/naszcard/sox = perl -c Clapper_jjw_lookups.pl
Clapper_jjw_lookups.pl syntax OK
naszcard@gustavo: /ou8/naszcard/sox = perl Clapper_jjw_lookups.pl -t
Could not connect to database: ORA-24327: need explicit attach before
authenticating a user (DBD ERROR: OCISessionBegin) at Clapper_jjw_lookups.pl
line 134.
FYI: line 134 is above - { AutoCommit=0, RaiseError=0, PrintError=0,
ora_check_sql=0 }) or die Could not connect to database: . DBI-errstr;
-So, after double-checking that I was using the correct SID, and banging my
head against the wall ;-), I commented out the 'use DBI;' and the section
above, and just tried to go straight to it, command line, and do it this way
instead:
my $tempCmd = sqlplus /nolog \@ . '/ou8/naszcard/sox/spool_lookup1b.sql ' .
$gustavoUser $gustavoPass | grep ORA;
@oracleErrors = '$tempCmd';
if(@oracleErrors ne 0) {
$tempDate = `date`;
chomp($tempDate);
my $tempORAError = join(/n,@oracleErrors);
system(echo \Clapper_jjw_lookups.pl has failed due to ORACLE ERROR(S): \n\n
It is $tempDate \n\n $tempORAError\ | mailx -s \Moja Table Lookups Errors\
\ $global_email \ );
exit;
}
~That produces this not very informative, error generated email:
-Original Message-
From: service - PRC [mailto:naszc...@acxiom.com]
Sent: Monday, July 30, 2012 10:51 PM
To: Warren James - jawarr
Subject: Moja Table Lookups Errors
Clapper_jjw_lookups1.pl has failed due to ORACLE ERROR(S):
It is Mon Jul 30 22:50:47 CDT 2012
(@oracleErrors is an array which doesn't seem to be working...)
*Here is the current, full text of my Perl code (passwords and other
sensitive, proprietary, etc., info. changed/hidden/masked to protect the
innocent ;-):
#!/usr/bin/perl
use strict;
use warnings;
#use DBI;
#use DBD::Oracle qw(:ora_types);
use Net::SFTP::Foreign;
use diagnostics;
## SCRIPT: Clapper_jjw_lookups.pl
## AUTHOR: James J. Warren -- jawarr
## NOTES: ERRORs logged and emailed
##
## First Perl script for James
##
# --
# Global Declaration --
# --
my $logPath = ; #-- Directory where all logs go (Does include last '/' )
my $codePath = ; #-- Directory where all scripts are (Does include last
'/' )
my $ftpDirectory = '/outbound/sftpp/xpj123/';
my $global_email = naszprod\@acxiom.com; # -- Global email (All emails
will be mailed to this address)
# my $dbh = ; # -- Database handle that will be initiated later
my $sth = ; # -- Statement handle that will be initiated later
my @oracleErrors;
my $fileConnectionString = ;
my $connString = ;
my $ladyUser = ;
my $ladyPass = ;
my $gustavoUser = ;
my $gustavoPass = ;
my @finishedSqlScripts;
my $tempQuery = ;
my $err_str = ;
# --
# End of Global Declaration ---
# --
my $startupCounter = 0;
our($opt_t);
init();
if ( $opt_t ){
$fileConnectionString = `cat ///xxx/logon.sql`; # -- The string
passed into the code that decides what user and password to use when login
into Oracle
$connString = 'dbi:Oracle:SID';
$logPath = '/xxx//logs/reporting/dev/';
$codePath = '/xxx//xxx/';
$ladyUser = \@lady;
$ladyPass = ;
$gustavoUser = ;
$gustavoPass = ;
$global_email = James.Warren\@acxiom.com;
}
else{
Re: case statement in perl
On Wed, Aug 01, 2012 at 12:02:04 -0400 , Uri Guttman wrote: On 08/01/2012 03:08 AM, Paul.G wrote: The example below is just a test, I need to be able to insert multiple values into a command, those values can be either 1, 2 or upto 5. you aren't getting the issue. the switch module was a major mistake and no one should be using it. you have to understand the downside to source filtering. no module can properly filter perl code as it is too subtle and complex to do so automatically. so source filters can seem to work now and if you do some changes to your code (not even near the switch stuff), it could break and you will have a hell of a time fixing it. the downside of that nasty hard to find bug is never worth it even if switch.pm appeals to you. modern perl's have a builtin given/when statement, you can use dispatch tables (especially for a fixed list of numbers or tokens) and other methods too. just avoid using the switch module. there is no way you can defend its use given the extremely nasty possible bugs it can introduce. +1 Though given/when is too smart for its own good, I agree with everything here. When uri and I agree on something, it's a strong indicator to pay attention. -- Chris Nehren | Coder, Sysadmin, Masochist Shadowcat Systems Ltd. | http://shadowcat.co.uk/ pgpWgsnYFeliD.pgp Description: PGP signature
Re: case statement in perl
so why don't they get rid of it? On Wed, Aug 1, 2012 at 2:33 PM, Chris Nehren c.nehren/beginn...@shadowcat.co.uk wrote: On Wed, Aug 01, 2012 at 12:02:04 -0400 , Uri Guttman wrote: On 08/01/2012 03:08 AM, Paul.G wrote: The example below is just a test, I need to be able to insert multiple values a command, those values can be either 1, 2 or upto 5. you aren't getting the issue. the switch module was a major mistake and no one should be using it. you have to understand the downside to source filtering. no module can properly filter perl code as it is too subtle and complex to do so automatically. so source filters can seem to work now and if you do some changes to your code (not even near the switch stuff), it could break and you will have a hell of a time fixing it. the downside of that nasty hard to find bug is never worth it even if switch.pm appeals to you. modern perl's have a builtin given/when statement, you can use dispatch tables (especially for a fixed list of numbers or tokens) and other methods too. just avoid using the switch module. there is no way you can defend its use given the extremely nasty possible bugs it can introduce. +1 Though given/when is too smart for its own good, I agree with everything here. When uri and I agree on something, it's a strong indicator to pay attention. -- Chris Nehren | Coder, Sysadmin, Masochist Shadowcat Systems Ltd. | http://shadowcat.co.uk/ -- - Chicago Hal Wigoda -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: case statement in perl
On Wed, Aug 01, 2012 at 14:38:42 -0500 , Hal Wigoda wrote: so why don't they get rid of it? I'm not sure which it you're referring to: Switch.pm or given/when. For better or worse, Perl has a strong culture of backwards compatibility. Perl is one of the few languages where you can use code written 10-20 years ago on a new version with few difficulties. As for given/when, there are some threads on the perl5-porters mailing list (where perl development is discussed) about changing given/when to something that is less ambiguous and less clever. As for Switch.pm, it has been removed from perl core. -- Chris Nehren | Coder, Sysadmin, Masochist Shadowcat Systems Ltd. | http://shadowcat.co.uk/ pgprSLgwr7Uhb.pgp Description: PGP signature
Re: updating variable in Parent using Parallel::ForkManager
On 2012-07-30 15:47, punit jain wrote:
my $pm = new Parallel::ForkManager(10);
my $count=0;
foreach my $user (@users) {
$pm-start($user) and next;
my $result;
--- do some processing ---
$pm-finish(0, \$result);
}
$pm-wait_all_children;
However the final value of count is not correct. Is there some race
condition on same variable updation by the processes ?
pm - run_on_finish (
sub {
my $result = @;
if (defined($result)) {
my $count += $result;
}
}
I wonder why you expect a parent variable to be available to a child.
I am ignoring the bugs and style issues in your code, because they are
not relevant to that point.
If you need to merge results from child-processes, it is best to let
those child-processes write to unshared resources. Rows with an
autoincrement-id in a database are often fine for that. A separate file
per child-process on disk can also be fine.
After all children exited, the parent collects all those results and
merges them.
Map: the parent divides the tasks over the children
Reduce: each child reduces its assigned input to a result
Merge: the parent combines all the results into the final result
--
Ruud
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Re: case statement in perl
I have removed the switch funtion from the script. From: Uri Guttman u...@stemsystems.com To: beginners@perl.org Sent: Thursday, 2 August 2012 2:02 AM Subject: Re: case statement in perl On 08/01/2012 03:08 AM, Paul.G wrote: The example below is just a test, I need to be able to insert multiple values into a command, those values can be either 1, 2 or upto 5. you aren't getting the issue. the switch module was a major mistake and no one should be using it. you have to understand the downside to source filtering. no module can properly filter perl code as it is too subtle and complex to do so automatically. so source filters can seem to work now and if you do some changes to your code (not even near the switch stuff), it could break and you will have a hell of a time fixing it. the downside of that nasty hard to find bug is never worth it even if switch.pm appeals to you. modern perl's have a builtin given/when statement, you can use dispatch tables (especially for a fixed list of numbers or tokens) and other methods too. just avoid using the switch module. there is no way you can defend its use given the extremely nasty possible bugs it can introduce. uri -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
