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Perlito Perl programming language compiler

Perlito, a compiler collection that implements Perl 5 and Perl 6.

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Perl to Java compiler

PPC Portable Perl Compiler

PPC Portable Perl Compiler

Flávio S. Glock

Booking.com

PPC Team

Perl to Java compiler

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• Why?

Fun: Hackathons, community

Technical: Typed variables; explore the limits

Business: Hadoop, Android

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Perl to Java compiler

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• Install from GitHub

https://github.com/fglock/Perlito

• Install from CPAN

https://metacpan.org/pod/Perlito5

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Not so easy in Java world

• No timely destruction
• DESTROY
• Auto-close files
• No XS
• Not Unix
• Long application startup time

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Nice things in Java world

• Lot of modules
• Threads
• Memory management

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Work in progress

• overload
• encoding

Perl5 Grammar

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token stmt_yadayada {

'...'

{

$MATCH->{capture} = Perlito5::AST::Apply->new(

code => 'die',

namespace => '',

arguments => [ Perlito5::AST::Buf->new( buf => 'Unimplemented' ) ],

);

}

};

​

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link: https://github.com/fglock/Perlito

Perl5 BEGIN blocks

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BEGIN {

for my $i ("first", "second", "third") {

*{"main::sub_$i"} = sub {

say "This is $i";

};

}

}

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java -jar perlito5.jar -I src5/lib -Cperl5 demo_begin.pl

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Perl5 eval-string

say "input: ";

my $x = <>;

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eval <<~'EOT';

chomp $x;

say '$x = ', $x;

say "next: ", ++$x;

EOT

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java -jar perlito5.jar -I src5/lib demo_eval.pl

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java -jar perlito5.jar -I src5/lib -Cjava demo_eval.pl

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Perl to Java compiler

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• Compiler generates plain Java code with no dependencies

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Perl to Java compiler

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// print “hello, World!\n”;

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PlCORE.print(

PlCx.VOID,

PlCx.STDOUT,

new PlArray(

new PlString("hello, World!" + (char)10)

)

);

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Perl to Java compiler

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• Shadow modules
• Internals
• PerlitoX::strict
• Platform specific - XS replacement
• PerlitoX::Java::MIME::Base64

Perl to Java compiler

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• Java imports should be hidden in modules
• Just like we move XS away from view
• use PerlitoX::Java namespace
• Main program should be plain perl

Java Extensions

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use feature 'say';

use strict;

package Calendar { import => "java.util.Calendar" }

package TimeZone { import => "java.util.TimeZone" }

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my Calendar $calNewYork = Calendar->getInstance();�

$calNewYork->setTimeZone(TimeZone->getTimeZone("America/New_York"));

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my $hour = $calNewYork->get(Calendar->HOUR_OF_DAY);

my $min = $calNewYork->get(Calendar->MINUTE);

say "Time in New York: $hour:$min";

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Dual object system

• Perl and Java objects
• Typed variables
• Import Java classes
• Integrates with HBase, Android

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https://github.com/fglock/Perlito/blob/master/misc/Java/TestThread2.pl

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perl perlito5.pl -Isrc5/lib -Cjava misc/Java/TestThread2.pl > Main.java ; javac Main.java ; java Main

Perl to Java compiler

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• Compiler Internals - Hackathon activities

Command line compiler

Runtime library

Parser development

DSL for Java imports

Compiler optimization

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Perl to Java compiler

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• Where is it used

Android test suite

Code extracted from “lib/Bookings/Tools/UserAgent.pm”

(code is not shared with main.git)

http-tests/src/test/perl/UserAgent.pm

http-tests/src/test/java/com/booking/common/http/UserAgentPerl.java

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Perl to Java compiler

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• Tools - Hackathon projects

Android development environment

Android specific targeting

Android <> Java SE

Integration with “Android Studio”

- Gradle task

- special “-Candroid” compiler switch

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Perl to Java compiler

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• Conclusion

about 10 people have worked in compiler internals.

We’ve used the Perl to Java compiler in places where rewriting code in Java was painful, such as in regex-heavy business rules.

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Perl to Java compiler

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• Current state

Still fun to work with, developing a community

Still technical challenges

Still going after more business

java -jar perlito5.jar -I src5/lib -Cjava camel.pl

Perl to Java compiler

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• Thanks!

Pugs, v6.pm: Audrey, "putter"

Perlito5: Jesse, “pmurias”, Shlomi, Simon

Perlito5-Java: Bosko, Yati, Bruno, Bas, Ovidiu,

Emmanuel, Frederico, Imran, Luca�

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Perlito Perl language compiler

Flávio S. Glock