Perl6 Michael Bryson Mark Staton Alex Varghese

Overview  Perl stands for practical extraction and report language  Was written as a language to scan text files, extract information from those files, and print reports based on that information

History  Perl1 was written around  Perl1 was mainly derived from C and to a lesser extent sed, awk, and the UNIX shell.  Perl1 was written for the file manipulation discussed earlier.

History (cont.)  Over the years, there have been many improvements in the language.  Perl now supports modularity and object- oriented programming.  Perl6 is the latest version and is a ground-up rewrite of the original source codes from versions 1 through 4.

History (cont.)  The evolution of Perl to the present day Perl6 allows programmers to perform or use:  Quick prototyping  System utilities  System management tasks  Database access  Graphical programming  Networking  World Wide Web programming

Interpreter/Compiler Perl is an interpreted language. This allows one to write programs without an intermediate compilation step. Not having a compilation step allows a programmer to experiment and test/debug quickly. Perl has also become a great replacement for shell scripting. Perl is an interpreted language. This allows one to write programs without an intermediate compilation step. Not having a compilation step allows a programmer to experiment and test/debug quickly. Perl has also become a great replacement for shell scripting.

Syntax  $ represents any scalar value represents a list  % represents a hash or associative array  You always need { } for any block in Perl. i.e. after an if statement  There are two sets of comparison operators. One set is for strings and the other is for numbers.

Parallel Data in Perl6  Junctions are a parallel scalar data-type, to be introduced in Perl 6  Four types of junctions:  Disjunctions  Conjunctions  Abjunctions  Injunctions

Disjunctions (any) $anyvalue = print “A number is too large” if $anyvalue > 10; can also be defined using binary operator (|) $anyvalue = $first | $second | $third; $third; $anyvalue |= $fourth;

Conjunctions (all) $allvalues = print “Must have positive number(s)” if $allvalues < 0; can also be defined using binary operator (&) $allvalues = $first & $second & $third; $third; $allvalues &= $fourth;

Abjunctions (one) $onevalue = print “There is exactly one zero” if $onevalue == 0;

Injunctions (none) $novalue = print “All negative numbers” if $novalue > 0;

More Junctions   Junctions can also be used implicitly:   print “all numbers must be positive” if $a|$b|$c < 0;   Junctions are simply scalars:   if (my_equals($value, {... }   Can be used for type declarations:   my Car|Truck $x;   my Car&RedObject $y;   my none(Truck) $z;   Allows for easy parallelization   if( sqrt( ) > 5 ) {... }

Comparisons  Perl’s expression syntax corresponds closely to C.  If you have experience with C or using UNIX, it is relatively easy to learn Perl.  On the surface, Perl and TCL are very similar. However, it is not until one is writing more complex programs and code that the differences become apparent.