Devel::REPL::Plugin::OutputCache - remember past results, _ is most recent

    > 21 / 7
    3
    > _ * _
    9
    > sub { die "later" }
    sub { die "later" }
    > _->()
    Runtime error: later

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.

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.

Devel::REPL, Devel::REPL::Plugin::History

Shawn M Moore, <sartak at gmail dot com>

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.