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Perl. Drew Murphy Drew Ebelhar. There’s more than one way to do it!. History. December 18, 1987 Creator- Larry Wall Objective: To develop a general purpose Unix scripting language to make report processing easier.
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Perl Drew Murphy Drew Ebelhar There’s more than one way to do it!
History • December 18, 1987 • Creator- Larry Wall • Objective: To develop a general purpose Unix scripting language to make report processing easier. • Gained widespread popularity in the late ‘90s as a CGI scripting language. • Perl 5 is the latest version, with Perl 6 currently under development.
Changes from 5 to 6 • Most changes attempt to normalize language. • Adds static typing to the already present dynamic typing. • Makes object-oriented programming easier. • Introduces feature similar to interfaces in Java. • Syntactical simplification.
Brief Overview • Perl is a high-level general purpose Unix based scripting language • Named “Perl” after the Parable of the Pearl in the Gospel of Matthew. • Occasionally backronymedPractical Extraction and Report Language. • Derived heavily from C. • Together with Python and PHP, form the three P’s of the internet, which denote the most popular dynamic languages for writing web applications.
Functional ity • TEXT MANIPULATION • CGI scripting • Graphics programming • System administration • Network programming • Bioinformatics • Lovingly referred to as the “Swiss army chainsaw of programming languages”, as well as the “duct tape that holds the internet together”.
Who’s using Perl? • Amazon • Craigslist • IMDb • Yahoo • Priceline
Design • While Fortran and C attempt to make efficient use of the expensive hardware, Perl makes efficient use of expensive programmersby making code easy to write. • Perl is extremely generous to the programmer at the expense of CPU and memory resources • The compiler is very forgiving and as a result debugging can be difficult • Does not enforce any particular paradigm(procedural,OOP,functional)
Sample Program – Hello World #!/usr/bin/perl use strict; use warning; my $hello = "Hello World!"; print $hello;
Some Code $ perl myscript.pl $myVar = 10; $myOtherVar = 9; $myString = “Some string.\n”; @someArray = (“An”,”Array”,”of”,”Strings”); print(“@someArray”); if($myVar != $myOtherVar) { print(“Ten does most definitely not equal nine.\n”); else{ print(“The universe exploded.\n”); } for $p (1..10) { print(“$p\n”); }
Readability • Pros • None. • Cons • Usually many ways to accomplish an operation. • Tolerates exceptions to its rules. • Large number of language primitives.
Writability • Pros • Easy to learn, yet extensive. • Supports many programming paradigms, such as objected-oriented, procedural, and functional programming. • Many built-in functions, such as sorting. • Can interact with other languages within code. • Cons • No writing standard for the language exists.
Reliability • Pros • Dynamic type checking. • Cons • Doesn’t require variable declaration unless the “use strict;” command is used. • Compiler is not strict, so bugs are difficult to find when present.
Cost • Pros • Easy to learn, so cost of training programmers is cheap. • Free • Uses hybrid implementation system, so compilation time is faster. • Available on many platforms. • Cons • Difficult to maintain or update programs, as there is generally poor readability.
References http://en.wikipedia.org/wiki/Perl http://en.wikipedia.org/wiki/Perl_6 http://www.perl.org/ http://perl-begin.org/learn/Perl-perl-but-not-PERL/ http://perl-begin.org/tutorials/perl-for-newbies/part1/ http://www.tizag.com/perlT/perlarrays.php
