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Full Discussion: Perl syntax
Top Forums Shell Programming and Scripting Perl syntax Post 302809215 by scj2012 on Saturday 18th of May 2013 08:06:13 PM
Old 05-18-2013
Quote:
Originally Posted by balajesuri
$tz is a reference variable that refers to the object obtained by blessing some package. site is a sub-routine (object method) in that package to which you're sending two arguments (as a list) viz. ['http','https'] and $site.

The single arrow (->) operator is called the dereference operator. In actual sense, a single arrow is used to refer to a value in a data structure (could be a scalar variable, list, hash, object). Observe the below example:
Code:
my $anonyArrRef = [ 1, 2, 3, 4, 5 ];
print "$anonyArrRef->[2]\n";

This will output 3, the 3rd number in the anonymous array whose reference is held in $anonyArrRef variable.

In your example, $tz is a reference variable that points to some object. And that object contains a sub-routine (object method) that is accessed by the thin arrow operator (->) -- $tz->site()A big arrow operator (=>) is just a notation used to represent key-value pairs while defining a hashmap.
Code:
my %hash = ('k1', 'v1', 'k2', 'v2); # One way to define a hash. Not so pleasing to human eye.
my %hash = ('k1' => 'v1', 'k2' => 'v2'); #Another way. Pleasing to human eye.
my %hash = (   'k1' => 'v1',
               'k2' => 'v2',
               'k3' => 'v3',
           ); # A little more creativity.

In your example, you're sending one key-value pair to sub-routine site, where the key is an anonymous array ['http','https'] and value is a scalar variable $site. Actually, the key would be a reference to this anonymous array.

Hope this helps.
Here is some more code. Comment on this.

Code:
my $tz = LWP::UserAgent->new; 
my $site = http://website.com 
$tz->site(['http','https'] => $site);

 

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rc.config

rc.config(4)						     Kernel Interfaces Manual						      rc.config(4)

NAME

       rc.config, rc.config.d - files containing system configuration information

SYNOPSIS

DESCRIPTION

       The  system  configuration  used  at  startup  is  contained in files within the directory The file sources all of the files within and and
       exports their contents to the environment.

   /etc/rc.config
       The file is a script that sources all of the scripts, and also sources To read the  configuration  definitions,	only  this  file  need	be
       sourced.   This	file  is  sourced by whenever it is run, such as when the command is run to transition between run states.  Each file that
       exists in is sourced, without regard to which startup scripts are to be executed.

   /etc/rc.config.d
       The configuration information is structured as a directory of files, rather than as a single file containing the  same  information.   This
       allows  developers  to  create and manage their own configuration files here, without the complications of shared ownership and access of a
       common file.

   /etc/rc.config.d/* Files
       This is where files containing configuration variable assignments are located.

       Configuration scripts must be written to be read by the POSIX shell, and not the Bourne shell, or In some cases, these files must  also	be
       read  and  possibly modified by control scripts or the sam program.  See sd(4) and sam(1M).  For this reason, each variable definition must
       appear on a separate line, with the syntax:

       No trailing comments may appear on a variable definition line.  Comment statements must be on separate lines, with the comment character in
       column one.  This example shows the required syntax for configuration files:

       Configuration variables may be declared as array parameters when describing multiple instances of the variable configuration.  For example,
       a system may contain two network interfaces, each having a unique IP address and subnet mask (see ifconfig(1M)).  An example of such a dec-
       laration is as follows:

       Note  that  there  must	be  no requirements on the order of the files sourced.	This means configuration files must not refer to variables
       defined in other configuration files, since there is no guarantee that the variable being referenced is currently  defined.   There  is	no
       protection  against  environment variable namespace collision in these configuration files.  Programmers must take care to avoid such prob-
       lems.

   /etc/TIMEZONE
       The file contains the definition of the environment variable.  This file is required by POSIX.  It is sourced by at the same time the files
       are sourced.

SEE ALSO

       rc(1M).

																      rc.config(4)
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