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A Short History of Complex Event Processing Part 3: the formative years
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Devel::REPL::Plugin::OutputCache(3pm) User Contributed Perl Documentation Devel::REPL::Plugin::OutputCache(3pm) NAME
Devel::REPL::Plugin::OutputCache - remember past results, _ is most recent SYNOPSIS
> 21 / 7 3 > _ * _ 9 > sub { die "later" } sub { die "later" } > _->() Runtime error: later DESCRIPTION
Re-using results is very useful when working in a REPL. With "OutputCache" you get "_", which holds the past result. The benefit is that you can build up your result instead of having to type it in all at once, or store it in intermediate variables. "OutputCache" also provides "$_REPL->output_cache", an array reference of all results in this session. Devel::REPL already has a similar plugin, Devel::REPL::Plugin::History. There are some key differences though: Input vs Output "History" remembers input. "OutputCache" remembers output. Munging vs Pure Perl "History" performs regular expressions on your input. "OutputCache" provides the "_" sub as a hook to get the most recent result, and "$_REPL->output_cache" for any other results. Principle of Least Surprise "History" will replace exclamation points in any part of the input. This is problematic if you accidentally include one in a string, or in a "not" expression. "OutputCache" uses a regular (if oddly named) subroutine so Perl does the parsing -- no surprises. CAVEATS
The "_" sub is shared across all packages. This means that if a module is using the "_" sub, then there is a conflict and you should not use this plugin. For example, Jifty uses the "_" sub for localization. Jifty is the only known user. SEE ALSO
"Devel::REPL", "Devel::REPL::Plugin::History" AUTHOR
Shawn M Moore, "<sartak at gmail dot com>" COPYRIGHT AND LICENSE
Copyright (C) 2007 by Shawn M Moore This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself. perl v5.14.2 2010-05-08 Devel::REPL::Plugin::OutputCache(3pm)
