3 package Devel::REPL::Plugin::OutputCache;
5 use Devel::REPL::Plugin;
6 use namespace::autoclean;
11 default => sub { [] },
15 has warned_about_underscore => (
22 around 'eval' => sub {
24 my ($self, $line) = @_;
26 my $has_underscore = *_{CODE};
27 if ($has_underscore && !$self->warned_about_underscore) {
28 warn "OutputCache: Sub _ already defined.";
29 $self->warned_about_underscore(1);
32 # if _ is removed, then we should warn about it again if it comes back
33 $self->warned_about_underscore(0);
36 # this needs to be a postfix conditional for 'local' to work
37 local *_ = sub () { $self->output_cache->[-1] } unless $has_underscore;
41 @ret = $self->$orig($line);
44 $ret[0] = $self->$orig($line);
47 push @{ $self->output_cache }, @ret > 1 ? \@ret : $ret[0];
48 return wantarray ? @ret : $ret[0];
57 Devel::REPL::Plugin::OutputCache - remember past results, _ is most recent
72 Re-using results is very useful when working in a REPL. With C<OutputCache> you
73 get C<_>, which holds the past result. The benefit is that you can build up
74 your result instead of having to type it in all at once, or store it in
75 intermediate variables. C<OutputCache> also provides
76 C<< $_REPL->output_cache >>, an array reference of all results in this session.
78 Devel::REPL already has a similar plugin, L<Devel::REPL::Plugin::History>.
79 There are some key differences though:
85 C<History> remembers input. C<OutputCache> remembers output.
87 =item Munging vs Pure Perl
89 C<History> performs regular expressions on your input. C<OutputCache> provides
90 the C<_> sub as a hook to get the most recent result, and
91 C<< $_REPL->output_cache >> for any other results.
93 =item Principle of Least Surprise
95 C<History> will replace exclamation points in any part of the input. This is
96 problematic if you accidentally include one in a string, or in a C<not>
97 expression. C<OutputCache> uses a regular (if oddly named) subroutine so Perl
98 does the parsing -- no surprises.
104 The C<_> sub is shared across all packages. This means that if a module is
105 using the C<_> sub, then there is a conflict and you should not use this
106 plugin. For example, L<Jifty> uses the C<_> sub for localization. Jifty is the
111 C<Devel::REPL>, C<Devel::REPL::Plugin::History>
115 Shawn M Moore, C<< <sartak at gmail dot com> >>
117 =head1 COPYRIGHT AND LICENSE
119 Copyright (C) 2007 by Shawn M Moore
121 This library is free software; you can redistribute it and/or modify
122 it under the same terms as Perl itself.