Add xCAT code standard doc page

docs/source/developers/guides/code/code_standard.rst

@@ -0,0 +1,92 @@
+Code Standard for Perl
+======================
+
+This document gives out a ``Code Standard`` for Perl programming in xCAT. All the Perl code which is checked in to xCAT code repository should follow this standard.
+
+This document does not give the coding rules one by one, but give a piece of example code. You need to follow the example code strictly.
+
+This standard referred to the Perl code style from perldoc: http://perldoc.perl.org/perlstyle.html
+
+Meanwhile, you are recommended to use following command line to tidy your code: ::
+
+    perltidy -w -syn -g -opt -i=4 -nt -io -nbbc -kbl=2 -pscf=-c -aws -pt=2 -bbc -nolc  <orig_code> -o <formatted_code>
+    
+Code Standard Example: ::
+
+    #! /usr/bin/perl
+    
+    # This is a perl program example to demo the recommended
+    # style to write perl code
+    
+    use strict;
+    use warnings;
+    
+    #--------------------------------------------------------------------------------
+    
+    =head3   subroutine_example
+        Descriptions:
+            This a subroutine to demo how to write perl code
+        Arguments:
+            param1: The first parameter
+            param2: The second parameter
+            param3: The third parameter
+        Returns:
+            0 - success
+            0 - fail
+    =cut
+    
+    #--------------------------------------------------------------------------------
+    sub subroutine_example {
+        my ($param1, $param2, $param3) = @_;
+    
+        print "In the subroutine subroutine_example.\n";
+    
+        return 0;
+    }
+    
+    
+    # Declar variables
+    my $a_local_scale;
+    my @a_local_array;
+    my %a_local_hash;
+    
+    $a_local_scale = 1;
+    
+    @a_local_array = ("a", "b", "c");
+    
+    %a_local_hash = (
+        "v1" => 1,
+        "v2" => 2,
+        "v3" => 3,
+    );
+    
+    # Demo how to check the key of hash
+    if (%a_local_hash and
+        defined($a_local_hash{v1}) and
+        defined($a_local_hash{v2}) and
+        defined($a_local_hash{v3})) {
+    
+        # Calculate the sum of values
+        my $sum_of_values = $a_local_hash{v1}
+          + $a_local_hash{v2}
+          + $a_local_hash{v3};
+    
+        print "The sum of values: $sum_of_values.\n";
+    }
+    
+    # Demo how to check whether the array is empty
+    if (@a_local_array) {
+        print "Has element in array: " . join(',', @a_local_array) . "\n";
+    }
+    elsif ($a_local_scale) {
+        print "The value of a scale variable: $a_local_scale.\n";
+    }
+    else {
+        # None of above
+        print "Get into the default path.\n";
+    }
+    
+    # Call the subroutine subroutine_example()
+    subroutine_example($a_local_scale, \@a_local_array, %a_local_hash);
+    
+    exit 0;

docs/source/developers/guides/code/index.rst

@@ -3,7 +3,8 @@ Code Development
 
 .. toctree::
    :maxdepth: 2
- 
+
+   code_standard.rst 
    builds.rst  
    debug.rst
    tips.rst