NAME

IO::Lambda::Backtrace - backtrace chains of events

DESCRIPTION

The module makes it easier to debug chains of events, when a lambda awaits for another, this one in turn for another, etc etc. 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 where each contains the caller lambda and the invocation point. The class provides helper methods for printing this information in readable form.

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 "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 also the additional perl stack trace is added.

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.