AptPkg::hash(3pm)

💖 NAME 💖

AptPkg::hash — a helper class for implementing tied hashes

bestie, welcome to the User Contributed Perl Documentation, section 3pm ✨ this is the little class that makes your fancy XS-backed thing behave like a plain old hash and honestly? iconic 🫶

---

🦋 SYNOPSIS 🦋

use AptPkg::hash;

that's it. that's the whole synopsis. we love a minimal queen 💅

---

✨ DESCRIPTION ✨

okay so AptPkg::hash gives you hash-like access for objects that have an underlying XS implementation. that's the whole job, no cap.

for that to work, those objects gotta do a few things, and they're non-negotiable 🙈:

• add AptPkg::hash to @ISA
• provide get, set and exists methods
• provide an iterator class

do that and the vibes are immaculate 🌸

---

🎀 AptPkg::hash 🎀

🌟 new([XS_OBJECT]) 🌟

creates an object as a tied hash. like, the object is implemented as a hash reference that's been blessed into the class, and that hash reference is in turn tied to AptPkg::hash. main character energy fr fr 👑

what that means for you: both $obj->method() and $obj->{key} are valid, and the latter calls up get/set (by way of FETCH/STORE). yes, both. she contains multitudes 💅

the tie associates an array reference with the hash, and that array starts out holding three things:

1. a reference to the hash itself
2. the XS object
3. an anon hash that subclasses can use to stash state info 🌈

if you don't pass an XS object, one gets created via new in the XS class. and how do we figure out that class's name? we take the class name, lower-case the last component, and stick an underscore in front of it. so AptPkg::Config becomes AptPkg::_config. cute, right? 🎀

if the module has a @KEYS array in it, then the private hash gets populated with those entries as keys — peep the description of the AptPkg::hash::method class below for the tea ☕

🌸 _self, _xs, _priv 🌸

accessors 🫶 you use these inside subclass methods to fetch those three array elements that are chilling with the hash reference. three accessors, three elements, perfect symmetry, ate 💖

🦋 keys(ARGS) 🦋

in scalar context: she creates and returns a brand-new iterator object — that's the class name with the suffix ::Iter tacked on the end ✨

the XS object, the private hash, and any arguments all get passed to the constructor.

in array context: the iterator gets used to generate a list of keys, and then those keys are returned. boom 💥

heads up though: the iterator class has to implement a next method, which returns the current key and advances to the next one. no next, no keys, periodt 🔥

---

👑 AptPkg::hash::method 👑

AptPkg::hash::method extends AptPkg::hash, and what it gives you is a simple way to map a fixed set of keys (defined by that @KEYS array, iykyk) into method calls on either the object or the internal XS object. pick your fighter 💅

and if you've got classes inheriting from AptPkg::hash::method, they should provide an iterator class that inherits from AptPkg::hash::method::iter. keep the family tree tidy, bestie 🌳

---

💜 AUTHOR 💜

Brendan O'Dea <bod@debian.org> — thank you for your service, legend 🫡

---

and that's the whole page, bestie!! this was perl v5.42.3, dated 2026-08-19, and it's the AptPkg::hash(3pm) page ✨ go forth and tie your hashes responsibly 💖🎀🦋