Make Your Own Perl with Moops
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This document discusses the history of extensibility in Perl, from early techniques using import subroutines and prototypes, to modern approaches like Devel::Declare, the keyword API, and Moops. Moops provides an easy and extensible way to define new syntax using Keyword::Simple, and was created to improve on earlier modules like MooseX::Declare by using a simpler design focused on extensibility. The document concludes by showing how Moops can be used to define a custom "setup" module that injects imports and extends the syntax, providing a cleaner way to share commonly used functions and roles.
![package My::Keyword;!
use Keyword::Simple;!
!
sub import { !
Keyword::Simple::define( !
class => sub { !
munge_code( $$_[0] );!
}!
);!
a real custom keyword](https://image.slidesharecdn.com/moops-141117003824-conversion-gate02/85/Make-Your-Own-Perl-with-Moops-38-320.jpg)
![package MyApp::Setup;!
use parent 'Moops';!
sub import { !
my $pkg = shift;!
my @imports = (!
'List::Util' => ['any'],!
'Scalar::Util' => ['blessed'],!
'experimental' => ['postderef']!
...!
);!
}
Moops-based setup class](https://image.slidesharecdn.com/moops-141117003824-conversion-gate02/85/Make-Your-Own-Perl-with-Moops-57-320.jpg)
Make Your Own Perl with Moops
- 1. flickr: philip66 Make your own Perl with M o o p s @friedo Mike Friedman London Perl Workshop 2014
- 3. A brief history… In the Beginning, Perl 5 was already extensible.
- 5. use Foo qw(bar); BEGIN {! require Foo;! Foo->import( ‘bar’ );! };
- 7. sub import {! my $pkg = shift;! ... a typical import sub
- 8. sub import {! my $pkg = shift;! my $callpkg = caller;! ... a typical import sub
- 9. sub import {! my $pkg = shift;! my $callpkg = caller;! my @imports = @_;! ... a typical import sub
- 10. sub import {! ... ! foreach ! my $sym(@imports) {! *{"${callpkg}::$sym"} = *{"${pkg}::$sym"} a typical import sub
- 12. A brief history… import is compile-time.
- 13. A brief history… import is compile-time. 1. add functions. 2. pretend they’re keywords.
- 14. package Adder;! ! sub import { ... }! sub add2 { ! return shift + 2;! } a pretend keyword
- 15. package Mine;! ! use Adder;! ! say add2 42; a pretend keyword
- 16. A brief history… Perl 5.2 ! Prototypes
- 17. Make fake keywords ! That behave like builtins
- 18. (kinda)
- 19. sub doblock(&@) { ! my $blk = shift;! return $blk->( @_ );! }! ! doblock { ! say $_ * $_ for @_;! } ( 1, 2, 3, 4, 5 );! a prototype pretend keyword
- 20. sub doblock(&) { ... }! ! doblock { ! say "first";! }! ! say "second"; a prototype pretend keyword
- 21. sub doblock(&) { ... }! ! doblock { ! say "first";! }! ! say "second"; a prototype pretend keyword # Fail :(
- 22. Prototype subs only work as expressions. ! Not statements.
- 23. sub doblock($&) { ... }! ! doblock name { ! say "first";! }! ! a prototype pretend keyword # Fail :(
- 24. a prototype pretend keyword # We have to say:
- 25. ! ! doblock name => sub { ! say "first";! };! ! a prototype pretend keyword # We have to say:
- 26. "&" prototypes are only magical if they're first.
- 27. A brief history… Perl 5.8 ! Devel::Declare
- 28. The first real way to add ! new syntax.
- 29. use MooseX::Declare;! ! class Foo { ! method bar { ... }! ...! }! ! a parser magic keyword
- 34. Devel::Declare is complicated •Declarators? •Scope injectors? •Method shadowing? •WTF?
- 35. MooseX::Declare is big, slow, and difficult to extend.
- 36. A brief history… Perl 5.12 ! The keyword API
- 37. Real keyword interface in the Perl core API.
- 38. package My::Keyword;! use Keyword::Simple;! ! sub import { ! Keyword::Simple::define( ! class => sub { ! munge_code( $$_[0] );! }! );! a real custom keyword
- 39. So... ! what is ! M o o p s ?
- 40. use Moops;! role NamedThing {! has name => ! (is => "ro", isa => Str);! }! ! class Person with NamedThing;! ... a Moops-defined class
- 42. Not exactly.
- 43. Not exactly. •Moo by default, but can use Moose
- 44. Not exactly. •Moo by default, but can use Moose •Uses Keyword::Simple for new syntax.
- 45. Not exactly. •Moo by default, but can use Moose •Uses Keyword::Simple for new syntax. •Uses Kavorka for functions/methods
- 46. Not exactly. •Moo by default, but can use Moose •Uses Keyword::Simple for new syntax. •Uses Kavorka for functions/methods •Designed for easy extensibility
- 47. A brief history… One year ago, ! I did this:
- 48. I like imports
- 50. package MyApp::Setup;! use Import::Into;! ! use List::Util ();! use List::MoreUtils ();! use Scalar::Util ();! use Const::Fast ();! use Try::Tiny ();! use Data::Alias ();! use autodie ();! ... Custom setup class
- 51. ! ! sub import { ! my $callpkg = caller;! Scalar::Util->import::into(! $callpkg, 'blessed', 'refaddr'! );! List::Util->import::into(! $callpkg, 'reduce', 'all', ...! );! ...! } Custom setup class
- 53. Unless I want to use custom syntax
- 54. use MooseX::Declare; ! # (or Moops)! ! class MyApp::Thing { ! use MyApp::Setup;! }! ! # :/! Custom setup class
- 55. I have to use the Setup class from within the right namespace.
- 56. What if the Setup class could also inject custom syntax?
- 57. package MyApp::Setup;! use parent 'Moops';! sub import { ! my $pkg = shift;! my @imports = (! 'List::Util' => ['any'],! 'Scalar::Util' => ['blessed'],! 'experimental' => ['postderef']! ...! );! } Moops-based setup class
- 58. sub import {! ...! $pkg->SUPER::import(! imports => @imports! );! }! ! ! # :D Moops-based setup class
- 59. Cool!
- 60. flickr: philip66 Questions @friedo Mike Friedman London Perl Workshop 2014