Commit | Line | Data |
cf51843c |
1 | package Devel::REPL::Plugin::OutputCache; |
2 | |
6a5409bc |
3 | use Devel::REPL::Plugin; |
e2d0b019 |
4 | use namespace::sweep; |
5 | use MooX::Types::MooseLike::Base qw(ArrayRef Bool); |
cf51843c |
6 | |
7 | has output_cache => ( |
8 | is => 'rw', |
e2d0b019 |
9 | isa => ArrayRef, |
cf51843c |
10 | default => sub { [] }, |
11 | lazy => 1, |
12 | ); |
13 | |
588f0734 |
14 | has warned_about_underscore => ( |
15 | is => 'rw', |
e2d0b019 |
16 | isa => Bool, |
17 | default => sub { 0 }, |
588f0734 |
18 | lazy => 1, |
19 | ); |
20 | |
cf51843c |
21 | around 'eval' => sub { |
22 | my $orig = shift; |
23 | my ($self, $line) = @_; |
24 | |
588f0734 |
25 | my $has_underscore = *_{CODE}; |
26 | if ($has_underscore && !$self->warned_about_underscore) { |
27 | warn "OutputCache: Sub _ already defined."; |
28 | $self->warned_about_underscore(1); |
29 | } |
30 | else { |
31 | # if _ is removed, then we should warn about it again if it comes back |
32 | $self->warned_about_underscore(0); |
33 | } |
34 | |
35 | # this needs to be a postfix conditional for 'local' to work |
36 | local *_ = sub () { $self->output_cache->[-1] } unless $has_underscore; |
cf51843c |
37 | |
38 | my @ret; |
39 | if (wantarray) { |
40 | @ret = $self->$orig($line); |
41 | } |
42 | else { |
43 | $ret[0] = $self->$orig($line); |
44 | } |
45 | |
46 | push @{ $self->output_cache }, @ret > 1 ? \@ret : $ret[0]; |
47 | return wantarray ? @ret : $ret[0]; |
48 | }; |
49 | |
50 | 1; |
51 | |
52 | __END__ |
53 | |
54 | =head1 NAME |
55 | |
56 | Devel::REPL::Plugin::OutputCache - remember past results, _ is most recent |
57 | |
58 | =head1 SYNOPSIS |
59 | |
60 | > 21 / 7 |
61 | 3 |
62 | > _ * _ |
63 | 9 |
64 | > sub { die "later" } |
65 | sub { die "later" } |
66 | > _->() |
67 | Runtime error: later |
68 | |
69 | =head1 DESCRIPTION |
70 | |
71 | Re-using results is very useful when working in a REPL. With C<OutputCache> you |
72 | get C<_>, which holds the past result. The benefit is that you can build up |
73 | your result instead of having to type it in all at once, or store it in |
74 | intermediate variables. C<OutputCache> also provides |
75 | C<< $_REPL->output_cache >>, an array reference of all results in this session. |
76 | |
77 | Devel::REPL already has a similar plugin, L<Devel::REPL::Plugin::History>. |
78 | There are some key differences though: |
79 | |
80 | =over 4 |
81 | |
82 | =item Input vs Output |
83 | |
84 | C<History> remembers input. C<OutputCache> remembers output. |
85 | |
86 | =item Munging vs Pure Perl |
87 | |
88 | C<History> performs regular expressions on your input. C<OutputCache> provides |
89 | the C<_> sub as a hook to get the most recent result, and |
90 | C<< $_REPL->output_cache >> for any other results. |
91 | |
92 | =item Principle of Least Surprise |
93 | |
94 | C<History> will replace exclamation points in any part of the input. This is |
95 | problematic if you accidentally include one in a string, or in a C<not> |
96 | expression. C<OutputCache> uses a regular (if oddly named) subroutine so Perl |
97 | does the parsing -- no surprises. |
98 | |
99 | =back |
100 | |
101 | =head1 CAVEATS |
102 | |
103 | The C<_> sub is shared across all packages. This means that if a module is |
104 | using the C<_> sub, then there is a conflict and you should not use this |
105 | plugin. For example, L<Jifty> uses the C<_> sub for localization. Jifty is the |
106 | only known user. |
107 | |
108 | =head1 SEE ALSO |
109 | |
110 | C<Devel::REPL>, C<Devel::REPL::Plugin::History> |
111 | |
112 | =head1 AUTHOR |
113 | |
114 | Shawn M Moore, C<< <sartak at gmail dot com> >> |
115 | |
116 | =head1 COPYRIGHT AND LICENSE |
117 | |
118 | Copyright (C) 2007 by Shawn M Moore |
119 | |
120 | This library is free software; you can redistribute it and/or modify |
121 | it under the same terms as Perl itself. |
122 | |
123 | =cut |