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
• Designing Perl module architecture
• Migrating pre-5.36 code to modern Perl

How It Works

Apply these patterns as a bias toward modern Perl 5.36+ defaults: signatures, explicit modules, focused error handling, and testable boundaries. The examples below are meant to be copied as starting points, then tightened for the actual app, dependency stack, and deployment model in front of you.

Core Principles

1. Use v5.36 Pragma

A single use v5.36 replaces the old boilerplate and enables strict, warnings, and subroutine signatures.

# Good: Modern preamble
use v5.36;

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

# Bad: Legacy boilerplate
use strict;
use warnings;
use feature 'say', 'signatures';
no warnings 'experimental::signatures';

sub greet {
    my ($name) = @_;
    say "Hello, $name!";
}

2. Subroutine Signatures

Use signatures for clarity and automatic arity checking.

use v5.36;

# Good: Signatures with defaults
sub connect_db($host, $port = 5432, $timeout = 30) {
    # $host is required, others have defaults
    return DBI->connect("dbi:Pg:host=$host;port=$port", undef, undef, {
        RaiseError => 1,
        PrintError => 0,
    });
}

# Good: Slurpy parameter for variable args
sub log_message($level, @details) {
    say "[$level] " . join(' ', @details);
}

# Bad: Manual argument unpacking
sub connect_db {
    my ($host, $port, $timeout) = @_;
    $port    //= 5432;
    $timeout //= 30;
    # ...
}

3. Context Sensitivity

Understand scalar vs list context — a core Perl concept.

use v5.36;

my @items = (1, 2, 3, 4, 5);

my @copy  = @items;            # List context: all elements
my $count = @items;            # Scalar context: count (5)
say "Items: " . scalar @items; # Force scalar context

4. Postfix Dereferencing

Use postfix dereference syntax for readability with nested structures.

use v5.36;

my $data = {
    users => [
        { name => 'Alice', roles => ['admin', 'user'] },
        { name => 'Bob',   roles => ['user'] },
    ],
};

# Good: Postfix dereferencing
my @users = $data->{users}->@*;
my @roles = $data->{users}[0]{roles}->@*;
my %first = $data->{users}[0]->%*;

# Bad: Circumfix dereferencing (harder to read in chains)
my @users = @{ $data->{users} };
my @roles = @{ $data->{users}[0]{roles} };

5. The isa Operator (5.32+)

Infix type-check — replaces blessed($o) && $o->isa('X').

use v5.36;
if ($obj isa 'My::Class') { $obj->do_something }

Error Handling

eval/die Pattern

use v5.36;

sub parse_config($path) {
    my $content = eval { path($path)->slurp_utf8 };
    die "Config error: $@" if $@;
    return decode_json($content);
}

Try::Tiny (Reliable Exception Handling)

use v5.36;
use Try::Tiny;

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

Native try/catch (5.40+)

use v5.40;

sub divide($x, $y) {
    try {
        die "Division by zero" if $y == 0;
        return $x / $y;
    }
    catch ($e) {
        warn "Error: $e";
        return;
    }
}

Modern OO with Moo

Prefer Moo for lightweight, modern OO. Use Moose only when its metaprotocol is needed.

# Good: Moo class
package User;
use Moo;
use Types::Standard qw(Str Int ArrayRef);
use namespace::autoclean;

has name  => (is => 'ro', isa => Str, required => 1);
has email => (is => 'ro', isa => Str, required => 1);
has age   => (is => 'ro', isa => Int, default  => sub { 0 });
has roles => 
how to use perl-patterns
CursorClaude CodeClineCodexWindsurfGooseGitHub CopilotVS CodeGemini CLIKiloOpencodeKimi CLIRoo ClineAiderContinueZedBolt.newLovablev0Replit AgentSweepSmol DeveloperDevinCavemanAmpAntigravity
How to use perl-patterns on Cursor
AI-first code editor with Composer
1
Prerequisites
Before installing skills in Cursor, ensure your development environment meets these requirements:
›Cursor installed and configured on your development machine
›Node.js version 16.0+ with npm package manager (verify with node --version)
›Active project directory or workspace where you want to add perl-patterns
2
Execute installation command
Execute the skills CLI command in your project's root directory to begin installation:
$npx skills add https://github.com/affaan-m/everything-claude-code --skill perl-patternscopy
The skills CLI fetches perl-patterns from GitHub repository affaan-m/everything-claude-code and configures it for Cursor.
3
Select Cursor when prompted
The CLI will show a list of available agents. Use arrow keys to navigate and space to select Cursor:
◆ Which agents do you want to install to?
│
│ ── Universal (.agents/skills) ── always included ────
│   • Amp
│   • Antigravity
│   • Cline
│   • Codex
│ ●Cursor(selected)
│   • Cursor
│   • Windsurf
4
Verify installation
Confirm successful installation by checking the skill directory location:
.cursor/skills/perl-patterns
Reload or restart Cursor to activate perl-patterns. Access the skill through slash commands (e.g., /perl-patterns) or your agent's skill management interface.
⚠
Security & Verification Notice
We perform automated surface-level scans (Gen AI Scanner, Socket, Snyk) during installation. These checks detect common vulnerabilities but do not guarantee complete security. Always review skill source code and verify the publisher's reputation before production use.
Skills execute code in your development environment. Always verify the publisher's identity, review recent commits, and test in isolated environments before production deployment.
Additional Resources
›View source code on GitHub›Skills CLI documentation›Learn more about Cursor›What are agent skills?