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Modern Perl


package User;

use Do 'Class';

has 'fname';
has 'lname';

method greet(Str $name) {
  my $fname = $self->fname;
  my $lname = $self->lname;

  "Hey $name, I'm $fname $lname";

package main;

my $user = User->new(fname => 'Al', lname => 'Newkirk');

say $user->greet('You');



This package aims to provide a modern Perl development framework and foundational set of types, functions, classes, patterns, and interfaces for jump-starting application development. This package inherits all behavior from Data::Object.


If you're doing something modern with Perl, start here!


This package provides a framework for modern Perl development, embracing Perl's multi-paradigm programming nature, flexibility and vast ecosystem that many of engineers already know and love. The power of this framework comes from the extendable (yet fully optional) type library which is integrated into the object system and type-constrainable subroutine signatures (supporting functions, methods and method modifiers). We also provide classes which wrap Perl 5 native data types and provides methods for operating on the data.


Contrary to the opinion of some, modern Perl programming can be extremely well-structured and beautiful, leveraging many advanced concepts found in other languages, and some which aren't. Abilities like method modification also referred to as augmentation, reflection, advanced object-orientation, type-constrainable object attributes, type-constrainable subroutine signatures (with named and positional arguments), as well roles (similar to mixins or interfaces in other languages). This framework aims to serve as an entrypoint to leveraging those abilities.

use Do;

The "Do" package is an alias and subclass of this package. It encapsulates all of the framework's features, is minimalist, and is meant to be the first import in a new class or module.

use Data::Object;

Both import statements are funcationally equivalent, enable the same functionality, and can be configured equally. This is what's enabled whenever you import the "Do" or "Data::Object" package into your namespace.

# basics
use strict;
use warnings;

# loads say, state, switch, etc
use feature ':5.14';

# loads type constraints
use Data::Object::Library;

# loads function/method signatures
use Data::Object::Signatures;

# imports keywords and super "do" function, etc
use Data::Object::Export;

# enables method calls on native data types
use Data::Object::Autobox;

To explain by way of example: The following established a user-defined type library where user-defined classes, roles, etc, will be automatically registered.

package App;

use Do 'Library';


The following creates a class representing a user which has the ability to greet another person. This class is type-library aware and will register itself as a type constraint.

package App::User;

use Do 'Class', 'App';

has name => (
  is  => 'ro',
  isa => 'Str',
  req => 1

method hello(AppUser $user) {
  return 'Hello '. $user->name .'. How are you?';


The following is a script which is type-library aware that creates a function that returns how one user greets another user.

package main;

use App::User;

use Do 'Core', 'App';

fun greetings(AppUser $u1, AppUser $u2) {
  return $u1->hello($u2);

my $u1 = User->new(name => 'Jane');
my $u2 = User->new(name => 'June');

say(greetings($u1, $u2)); # Hello June ...

This demonstrates much of the power of this framework in one simple example. If you're new to Perl, the code above creates a class with a single (read-only string) attribute called name and a single method called hello, then registers the class in a user-defined type-library called App where all user-defined type constraints will be stored and retrieved (and reified). The main program (namespace) initializes the framework and specifies the user-defined type library to use in the creation of a single function greetings which takes two arguments which must both be instances of the class we just created. Please see Data::Object for more information and usages.


It's important to note that while the example showcases much of what's possible with this framework, all of the sophistication is totally optional. For example, method and function signatures are optionally typed, so the declarations would work just as well without the types specified. In fact, you could then remove the App type library declarations and even resort rewriting the method and function as plain-old Perl subroutines. This flexibility to be able to enable more advanced capabilities is common in the Perl ecosystem and is one of the things we love most. The wiring-up of things! If you're familiar with Perl, this framework is in-part the wiring up of Moo (with Moose support), Type::Tiny, Function::Parameters, Try::Tiny and data objects in a cooperative and cohesive way that feels like it's native to the language. Please feel free to use as much or as little of the framework as you need and are comfortable with.


If you have cpanm, you only need one line:

$ cpanm -qn Do

If you don't have cpanm, get it! It takes less than a minute, otherwise:

$ curl -L | perl - -qn Do

Add Do to the list of dependencies in cpanfile:

requires "Do" => "1.60"; # 1.60 or newer

If cpanm doesn't have permission to install modules in the current Perl installation, it will automatically set up and install to a local::lib in your home directory. See the local::lib documentation for details on enabling it in your environment. We recommend using a Perlbrew or Plenv environment. These tools will help you manage multiple Perl installations in your $HOME directory. They are completely isolated Perl installations.


Al Newkirk, +289

Anthony Brummett, +10

José Joaquín Atria, +1


Al Newkirk,


Copyright (C) 2011-2019, Al Newkirk, et al.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.








To get the most out of this distribution, consider reading the following:








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