plugins

3 files changed, 88 insertions, 9 deletions

diff --git a/lib/App/REPL.pm b/lib/App/REPL.pm
index 0ec1e63..f9262fb 100644
--- a/lib/App/REPL.pm
+++ b/lib/App/REPL.pm
@@ -2,16 +2,22 @@ package App::REPL;
 use strict;
 use warnings;
 
+use App::REPL::Plugin::Defaults;
+
 sub new {
-    bless {}, shift;
+    bless {
+        plugins => [
+            App::REPL::Plugin::Defaults->new,
+        ]
+    }, shift;
 }
 
 sub run {
     my $self = shift;
 
     while (defined(my $line = $self->_read)) {
-        my $result = $self->_eval($line);
-        $self->_print($result);
+        my @result = $self->_eval($line);
+        $self->_print(@result);
     }
     print "\n";
 }
@@ -19,23 +25,55 @@ sub run {
 sub _read {
     my $self = shift;
 
-    print "> ";
-    return <>;
+    $self->_wrapped_plugin('display_prompt');
+    my ($line) = $self->_wrapped_plugin('read_line');
+    ($line) = $self->_chained_plugin('munge_line', $line);
+
+    return $line;
 }
 
 sub _eval {
     my $self = shift;
     my ($line) = @_;
 
-    return eval $line;
+    return $self->_wrapped_plugin('evaluate', $line);
 }
 
 sub _print {
     my $self = shift;
-    my ($result) = @_;
+    my (@result) = @_;
+
+    @result = $self->_chained_plugin('munge_result', @result);
+    $self->_wrapped_plugin('print_result', @result);
+}
+
+sub _wrapped_plugin {
+    my $self = shift;
+    my $plugins = ref($_[0]) ? pop : $self->{plugins};
+    my ($method, @args) = @_;
+
+    $plugins = [ grep { $_->can($method) } @$plugins ];
+
+    return @args unless @$plugins;
+
+    my $plugin = shift @$plugins;
+    my $next = sub { $self->_wrapped_plugin($plugins, @_) };
+
+    return $plugin->$method($next, @args);
+}
+
+sub _chained_plugin {
+    my $self = shift;
+    my $plugins = ref($_[0]) ? pop : $self->{plugins};
+    my ($method, @args) = @_;
+
+    $plugins = [ grep { $_->can($method) } @$plugins ];
+
+    for my $plugin (@$plugins) {
+        @args = $plugin->$method(@args);
+    }
 
-    print $result, "\n"
-        if defined $result;
+    return @args;
 }
 
 1;
diff --git a/lib/App/REPL/Plugin.pm b/lib/App/REPL/Plugin.pm
new file mode 100644
index 0000000..a255f62
--- /dev/null
+++ b/lib/App/REPL/Plugin.pm
@@ -0,0 +1,7 @@
+package App::REPL::Plugin;
+use strict;
+use warnings;
+
+sub new { bless {}, shift }
+
+1;
diff --git a/lib/App/REPL/Plugin/Defaults.pm b/lib/App/REPL/Plugin/Defaults.pm
new file mode 100644
index 0000000..f2b4705
--- /dev/null
+++ b/lib/App/REPL/Plugin/Defaults.pm
@@ -0,0 +1,34 @@
+package App::REPL::Plugin::Defaults;
+use strict;
+use warnings;
+
+use base 'App::REPL::Plugin';
+
+sub display_prompt {
+    my $self = shift;
+
+    print "> ";
+}
+
+sub read_line {
+    my $self = shift;
+
+    return scalar <>;
+}
+
+sub evaluate {
+    my $self = shift;
+    my ($next, $line) = @_;
+
+    return eval $line;
+}
+
+sub print_result {
+    my $self = shift;
+    my ($next, $result) = @_;
+
+    print $result, "\n"
+        if defined $result;
+}
+
+1;