Perl OOP and reference

Perl can do OOP for sure. I reviewed relevant material for recent work. Use "Package" to define a class. What's interesting is the use of "bless" keyword. An object is used in the syntax of a C++ object, say you use "->" to retrieve its member variable or function.

The use of reference facilitates a lot of programming features. In Perl using a back slash "\" in front of a variable (scalar, array or hash) turns it into a reference. This can be passed to subroutines, to be used recursively etc. To cast it back and refer to the object, use $/@{}/%{} for scalar/array/hash respectively.

References:
- Object Oriented Programming in PERL

Perl - count number of occurrences

http://www.chengfu.net/2005/10/count-occurrences-perl/

The author wants to find out what's the fastest way of counting occurrences of a string in a text. e.g. '-' in “1-4-7-8-37-5-7-8-3-42″. He gives 5 ways of doing this:

1. my $size = (scalar(@{[$string =~ /-/g]}) + 1);
2. my $size = scalar(split /-/, $string);
3. my $size = (($string =~ s/-//g) + 1);
4. my $size = (($string =~ tr/-//) + 1);
5. my $size = 1; $size++ while $string =~ /-/g;

He found the speed to be 4, 3, 5, 1, 2 in the order of fastest to slowest on his machine.

Doodling in math class

Doodling in math class: http://vihart.com/doodling/

Interesting.

Perlpod

Perlpod: The Plain Old Document format.

Description about Perlpod from the above source:

Pod is a simple-to-use markup language used for writing documentation for Perl, Perl programs, and Perl modules.
Translators are available for converting Pod to various formats like plain text, HTML, man pages, and more.
Pod markup consists of three basic kinds of paragraphs: ordinary, verbatim, and command.

Setup email forwarding in linux/unix

Email forwarding can be setup in an email client such as Thunderbird.

Under linux/unix, it can done by admin or by user himself, as explained here.

To do it by the user himself, he only needs to create a file .forward in his account root, and enter the forward email addresses separated by comma or new line. The .forward file should have permission 644.

An example .forward file is:

"|/usr/local/bin/procmail"
example@gmail.com

Java becomes closed source

December 9, 2010: The ASF Resigns From the JCP Executive Committee.

It seems that now Java to Oracle is as C# to Microsoft. Java becomes proprietary language of Oracle. But, C/C++/PHP/Perl/Python/Ruby are still open source.

Since Oracle also owns MySQL, don't know what will happen to MySQL. PostgreSQL is still open source though.

Silicon valley

Here is an introduction to silicon valley.