Sunday, March 22, 2015

Few basic tips about Perl programming

Perl development
Perl is a programming language on UNIX or Linux operating systems. It is a family of powerful, mature, stable and portable programming and feature rich languages. Originally Perl was developed in the form of a general UNIX scripting language for making it easier to process reports. It has undergone various revisions and changes since its initial development. Perl languages usually borrow features from different programming languages like shell scripting (sh), C and many others.

Always Benchmark the Code
It is important to assess the performance of a program. Such performance assessing can be done by timing a piece of code. The process of timing can be performed using certain Perl modules that are available and is simple to perform.

Necessary to Benchmark Modules
There are a number of useful modules in Comprehensive Perl Archive Network. The code present in the CPAN is thoroughly tested as well as improved by the Perl development community. While focusing on the performance aspect of an application, it is essential not only to benchmark code but at the same time go for benchmarking the modules that are being used. While using the modules, care needs to be taken on the part of the programmers.

Use my function to localize variables
Perl consists of ‘my function’ that is used to create lexical variables. The programming language only manages memory usage on the part of the Perl programmers and it does not see if he uses the variable later. Therefore, in case of variable creation in a particular subroutine, it is necessary to declare using ‘my function’. In doing so, variable memory is reclaimed at the end of the subroutine.

Always stay away from Slurping
Whenever the coding process is done, the input record separator remains undefined. This results in slurping or read in the entire file. The slurping process is inefficient with large files. Processing a line at a time requires the use of the while loop. There are situations when processing a line at a time is not possible and the slurping is unavoidable. Benchmarking the code enables to see the penalty imposed by slurping process.

The use of undef versus ( )
Reusing an array in shell requires clearing them instead of not defining them. Undefining an array in order to clear it makes Perl to deallocate the space having the data. Populating the array with data requires reallocating the space again. This slows the programming process.

The utility of Self Loader module
It is a module that hides subroutines and functions. It is because of this the interpreter associated with the language does not compile them to operation codes (opcodes) upon loading a PERL application. Compiling is done only when it is necessary. This process makes the programming very efficient.

Use the auto use feature
When external modules are used in the application then the atouse feature delays the loading process unless a particular function from a module is used.

Need to Avoid the Shell
It is preferable to avoid the shell unless it is absolutely necessary. There are other functions for different UNIX commands. These functions need to be used instead of the shell, whenever required.

Refer to Existing Solutions for Your Problems
With respect to Perl web development, it is quite natural for the programmer to get stuck with an issue. In case somebody faced similar issue earlier, the programmer can then simply borrow the code instead of spending time in developing the solution.

It is also important for IT professionals using the software to refer to certain books on the topics, learn useful algorithms, tricks as well as tips.

Use Regular Expressions when required
Regular expressions need to be used as these are the fundamental aspects of the language. CGI applications often use them.

Programming using PERL is nothing much complicated and becomes more convenient if one follows certain tips and tricks associated with it. These tips basically increase the efficiency of the programming language. A proficient programmer is able to identify the right method at the right time for developing a solution making use of the language.

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