Introducing Perl - Version VI: A New Hope
Grant McLean^H^H^H^HSam Vilain
grantm^H^H^Hsamv@cpan.org
What is Perl 6?
A new high level programming language
Designed by @Larry
Bears a striking resemblance to this other language called
Perl 5, in much of its syntax and feel
Also Open Source
- programming vs scripting - offline
- compiled vs interpreted - offline
- procedural/object oriented/functional? - Yes
- Larry also wrote 'patch' (and 'rn')
- one of the original Open Source projects
- Perl 1 released in 1987 (4 years before Linux)
- Perl 5 released in 1994
- Uncle Sam wants lazy programmers image?
Cool things about Perl 6
'Clean' re-write - Lots of Broken As Designed(TM) things fixed
Optional Strict Typing
Objects in core
Rules-based programming
Higher Order functions
Interpreter independance
Grammar mutation, macros
Continuations and Coroutines
- Second System by people fully aware of SSD
- Objects system is Roles-based, like Smalltalk traits or Haskell classes
What can Perl 6 be used for?
Everything Perl 5 could
Writing compiled programs
Writing BIG programs
Writing compilers and parsers via rules and types
system(s)
Simpler Application Servers via continuations
...
Our first Perl program
)> World! (The time is 16:03)
samv:~/utsl/pm/perl-intro$ ]]>
good_practice.p6
1, 'II' => 2, 'III' => 3, 'IV' => 4);
print $roman{'III'}, "\n";
print join(', ', keys(%roman)), "\n";
while(my($key, $value) = each(%roman)) {
print "$key = $roman{$key}\n";
}
delete($roman{IV});
print join(', ', @roman{'I', 'II', 'III'}), "\n";
]]>
Perl 6 Data Types: hashes
1, 'II' => 2, 'III' => 3, 'IV' => 4);
say %roman{'III'};
say %roman.keys.join(", ");
for %roman.kv -> $key, $value {
say "$key = $value";
}
%roman.delete;
say %roman.join(', ');
]]>
- again, sigil stays the same
- list results can be chained
- pointy subs
- angle lookups
Perl 5 Syntax: while loop
) {
print if(/$pattern/);
}
]]>
A Perl 6 implementation of 'grep'
) {
print $foo if $foo ~~ m:perl5/$pattern/;
}
]]>
- =$foo syntax for iterators
- m:perl5: for pcre
Perl 5 Syntax: for loop
$count {
say $count;
}
]]>
Or:
Auckland:
Graeme Barker grabar@xtra.co.nz 027 555 1234
Martin Fenwick m.fenwick@clear.net.nz 021 555 5432
Waikato:
Fiona Winters fiwi@mooloo.net.nz 021 555 8113
Justin Hiraka justinh@xtra.co.nz 027 555 289
Hawkes Bay:
Michael Teller mike.teller@bay.net.nz 027 555 9753
Output:
INSERT INTO dealer VALUES (
'Graeme', 'Barker', 'grabar@xtra.co.nz',
'027 555 1234', 'Auckland'
);
Data munging continued
) {
if(/^([a-zA-Z ]+):\s*$/) {
$region = $1;
next;
}
if(/^(\w+)\s+(\w+)\s+(\S*?@\S+)\s+(\d+(?:\s+\d+)*)/) {
print "INSERT INTO dealer VALUES (",
"'$1', '$2', '$3', '$4', '$region');\n";
}
}
]]>
- earlier 'grep' example opened files implicitly, explicit here
- regular expressions for pattern matching
- if it looks like a region, store it in global (next to short-circuit)
- if it looks like a record, print out in appropriate form
- naive regex doesn't handle apostrophes, hyphens, 3 names etc
Data munging continued
Template::MasonLite->new_from_file('./_index.html'),
toc => Template::MasonLite->new_from_file('./_toc.html'),
slide => Template::MasonLite->new_from_file('./_slide.html'),
notes => Template::MasonLite->new_from_file('./_notes.txt'),
);
my $file = 'talk.xml';
my $parser = XML::LibXML->new;
my $doc = $parser->parse_file($file);
my $root = $doc->getDocumentElement;
gen_title_page($root);
gen_contents_page($root);
gen_slides($root);
gen_notes($root);
exit;
sub gen_title_page {
my($doc) = @_;
...
]]>
Grant's XML slide generator - module
Template::MasonLite->new_from_file('./_index.html'),
toc => Template::MasonLite->new_from_file('./_toc.html'),
slide => Template::MasonLite->new_from_file('./_slide.html'),
notes => Template::MasonLite->new_from_file('./_notes.txt'),
);
sub new {
bless {}, shift;
}
sub get_xmldoc {
shift;
my $file = shift;
my $parser = XML::LibXML->new;
my $doc = $parser->parse_file($file);
my $root = $doc->getDocumentElement;
return $root;
}
sub gen_title_page {
shift;
...
]]>
mkpres.p6