Drew Murphy Drew Ebelhar

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 backronymed Practical 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 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”. ity

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 programmers by 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; $myString = “Some = (“An”,”Array”,”of”,”Strings”); if($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.

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