affaan-m--everything-claude-code/rules/perl/patterns.md

---
paths:
  - "**/*.pl"
  - "**/*.pm"
  - "**/*.t"
  - "**/*.psgi"
  - "**/*.cgi"
---
# Perl Patterns

> This file extends [common/patterns.md](../common/patterns.md) with Perl-specific content.

## Repository Pattern

Use **DBI** or **DBIx::Class** behind an interface:

```perl
package MyApp::Repo::User;
use Moo;

has dbh => (is => 'ro', required => 1);

sub find_by_id ($self, $id) {
    my $sth = $self->dbh->prepare('SELECT * FROM users WHERE id = ?');
    $sth->execute($id);
    return $sth->fetchrow_hashref;
}
```

## DTOs / Value Objects

Use **Moo** classes with **Types::Standard** (equivalent to Python dataclasses):

```perl
package MyApp::DTO::User;
use Moo;
use Types::Standard qw(Str Int);

has name  => (is => 'ro', isa => Str, required => 1);
has email => (is => 'ro', isa => Str, required => 1);
has age   => (is => 'ro', isa => Int);
```

## Resource Management

- Always use **three-arg open** with `autodie`
- Use **Path::Tiny** for file operations

```perl
use autodie;
use Path::Tiny;

my $content = path('config.json')->slurp_utf8;
```

## Module Interface

Use `Exporter 'import'` with `@EXPORT_OK` — never `@EXPORT`:

```perl
use Exporter 'import';
our @EXPORT_OK = qw(parse_config validate_input);
```

## Dependency Management

Use **cpanfile** + **carton** for reproducible installs:

```bash
carton install
carton exec prove -lr t/
```

## Reference

See skill: `perl-patterns` for comprehensive modern Perl patterns and idioms.