1 package Devel::REPL::Plugin::OutputCache;
3 use Devel::REPL::Plugin;
4 use namespace::clean -except => [ 'meta' ];
13 has warned_about_underscore => (
20 around 'eval' => sub {
22 my ($self, $line) = @_;
24 my $has_underscore = *_{CODE};
25 if ($has_underscore && !$self->warned_about_underscore) {
26 warn "OutputCache: Sub _ already defined.";
27 $self->warned_about_underscore(1);
30 # if _ is removed, then we should warn about it again if it comes back
31 $self->warned_about_underscore(0);
34 # this needs to be a postfix conditional for 'local' to work
35 local *_ = sub () { $self->output_cache->[-1] } unless $has_underscore;
39 @ret = $self->$orig($line);
42 $ret[0] = $self->$orig($line);
45 push @{ $self->output_cache }, @ret > 1 ? \@ret : $ret[0];
46 return wantarray ? @ret : $ret[0];
55 Devel::REPL::Plugin::OutputCache - remember past results, _ is most recent
70 Re-using results is very useful when working in a REPL. With C<OutputCache> you
71 get C<_>, which holds the past result. The benefit is that you can build up
72 your result instead of having to type it in all at once, or store it in
73 intermediate variables. C<OutputCache> also provides
74 C<< $_REPL->output_cache >>, an array reference of all results in this session.
76 Devel::REPL already has a similar plugin, L<Devel::REPL::Plugin::History>.
77 There are some key differences though:
83 C<History> remembers input. C<OutputCache> remembers output.
85 =item Munging vs Pure Perl
87 C<History> performs regular expressions on your input. C<OutputCache> provides
88 the C<_> sub as a hook to get the most recent result, and
89 C<< $_REPL->output_cache >> for any other results.
91 =item Principle of Least Surprise
93 C<History> will replace exclamation points in any part of the input. This is
94 problematic if you accidentally include one in a string, or in a C<not>
95 expression. C<OutputCache> uses a regular (if oddly named) subroutine so Perl
96 does the parsing -- no surprises.
102 The C<_> sub is shared across all packages. This means that if a module is
103 using the C<_> sub, then there is a conflict and you should not use this
104 plugin. For example, L<Jifty> uses the C<_> sub for localization. Jifty is the
109 C<Devel::REPL>, C<Devel::REPL::Plugin::History>
113 Shawn M Moore, C<< <sartak at gmail dot com> >>
115 =head1 COPYRIGHT AND LICENSE
117 Copyright (C) 2007 by Shawn M Moore
119 This library is free software; you can redistribute it and/or modify
120 it under the same terms as Perl itself.