perl-patterns

name	perl-patterns
description	Modern Perl 5.36+ idioms, best practices, and conventions for building robust, maintainable Perl applications.
origin	ECC

Modern Perl Development Patterns

Idiomatic Perl 5.36+ patterns and best practices for building robust, maintainable applications.

When to Activate

• Writing new Perl code or modules
• Reviewing Perl code for idiom compliance
• Refactoring legacy Perl to modern standards
• Migrating pre-5.36 code to modern Perl

Core Principles

1. Use v5.36 Pragma

use v5.36;

sub greet($name) {
    say "Hello, $name!";
}

2. Subroutine Signatures

sub connect_db($host, $port = 5432, $timeout = 30) {
    return DBI->connect("dbi:Pg:host=$host;port=$port", undef, undef, {
        RaiseError => 1,
        PrintError => 0,
    });
}

3. Postfix Dereferencing

my @users = $data->{users}->@*;
my @roles = $data->{users}[0]{roles}->@*;

Error Handling

Try::Tiny

use Try::Tiny;

my $user = try {
    $db->resultset('User')->find($id) // die "User $id not found\n";
} catch {
    warn "Failed to fetch user $id: $_";
    undef;
};

Modern OO with Moo

package User;
use Moo;
use Types::Standard qw(Str Int ArrayRef);

has name  => (is => 'ro', isa => Str, required => 1);
has email => (is => 'ro', isa => Str, required => 1);
has roles => (is => 'ro', isa => ArrayRef[Str], default => sub { [] });

sub is_admin($self) {
    return grep { $_ eq 'admin' } $self->roles->@*;
}
1;

Quick Reference

Legacy Pattern	Modern Replacement
use strict; use warnings;	use v5.36;
my ($x, $y) = @_;	sub foo($x, $y) { ... }
@{ $ref }	$ref->@*
open FH, "< $file"	open my $fh, '<:encoding(UTF-8)', $file
blessed hashref	Moo class with types
$1, $2, $3	$+{name} (named captures)

Anti-Patterns

• Two-arg open (security risk)
• Indirect object syntax (new Foo() instead of Foo->new())
• Disabling strict refs
• String eval for module loading