IO::Lam...acktrace(3)

📦 version 1.34, in alpine 3.24

💖 NAME 💖

okay so bestie, welcome to IO::Lam...acktrace(3) from the User Contributed Perl Documentation — and the main character here is IO::Lambda::Backtrace, aka the module for backtrace chains of events. 💅✨

🦋 DESCRIPTION 🦋

Picture it: a lambda is awaiting another lambda, and that one is in turn awaiting another, etc etc, and the chain is literally giving absolute chaos. 😭 This module makes debugging those chains of events easier.

The class IO::Lambda::Backtrace represents a set of such stacks, because a lambda can be awaited by more than one lambda. Each stack is an array of items, and each item contains the caller lambda and the invocation point. 📚🫶

The class provides helper methods for printing this information in readable form. Slay, periodt.

The module relies on the debug information about invocation points collected by IO::Lambda. By default, there's very little information collected, so in order to increase verbosity use the IO::Lambda::DEBUG_CALLER flag — either directly or through $ENV{IO_LAMBDA_DEBUG} = 'caller'. If the flag is set to 1, lambdas collect invocation points. If the flag is set to 2, then the additional perl stack trace is added too. 🔥

ngl bestie, default debug info is lowkey crumbs — turn up the flag if you want the full tea. 🍓

🌸 SYNOPSIS 🌸

use IO::Lambda;
$IO::Lambda::DEBUG_CALLER = 1;

lambda {
   ...
   warn this-> backtrace-> as_text;
}

or from command line:

env IO_LAMBDA_DEBUG=caller=2 ./myscript

🎀 API 🎀

  • new($lambda) — extracts the information of the current chain of events and creates a new blessed reference of it. ✨
  • as_text — returns the backtrace information formatted as text, ready to display. 💖
  • cluck — warns with the backtrace log. 🫶
  • confess — dies with the backtrace log. 💀

👑 AUTHOR 👑

Dmitry Karasik, <dmitry@karasik.eu.org>. 💌

The ideas of backtracing threads of events, and implementing backtrace objects passable through execition stack are proposed by Ben Tilly. 🌈

okay that's the whole vibe check, bestie 😌 this is perl v5.42.2, dated 2026-02-15, and it's the IO::Lam...acktrace(3) page from the User Contributed Perl Documentation. mwah 💋

📦 where this page comes from