Moose-2.1405HEADMoose-2.1405master

1 files changed, 155 insertions, 0 deletions

diff --git a/t/examples/example2.t b/t/examples/example2.t
new file mode 100644
index 0000000..fae26dd
--- /dev/null
+++ b/t/examples/example2.t
@@ -0,0 +1,155 @@
+use strict;
+use warnings;
+
+use Test::More;
+use Test::Fatal;
+
+sub U {
+    my $f = shift;
+    sub { $f->($f, @_) };
+}
+
+sub Y {
+    my $f = shift;
+    U(sub { my $h = shift; sub { $f->(U($h)->())->(@_) } })->();
+}
+
+{
+    package List;
+    use Moose::Role;
+
+    has '_list' => (
+        is       => 'ro',
+        isa      => 'ArrayRef',
+        init_arg => '::',
+        default  => sub { [] }
+    );
+
+    sub head { (shift)->_list->[0] }
+    sub tail {
+        my $self = shift;
+        (ref $self)->new(
+            '::' => [
+                @{$self->_list}[1 .. $#{$self->_list}]
+            ]
+        );
+    }
+
+    sub print {
+        join ", " => @{$_[0]->_list};
+    }
+
+    package List::Immutable;
+    use Moose::Role;
+
+    requires 'head';
+    requires 'tail';
+
+    sub is_empty { not defined ($_[0]->head) }
+
+    sub length {
+        my $self = shift;
+        (::Y(sub {
+            my $redo = shift;
+            sub {
+                my ($list, $acc) = @_;
+                return $acc if $list->is_empty;
+                $redo->($list->tail, $acc + 1);
+            }
+        }))->($self, 0);
+    }
+
+    sub apply {
+        my ($self, $function) = @_;
+        (::Y(sub {
+            my $redo = shift;
+            sub {
+                my ($list, $func, $acc) = @_;
+                return (ref $list)->new('::' => $acc)
+                    if $list->is_empty;
+                $redo->(
+                    $list->tail,
+                    $func,
+                    [ @{$acc}, $func->($list->head) ]
+                );
+            }
+        }))->($self, $function, []);
+    }
+
+    package My::List1;
+    use Moose;
+
+    ::is( ::exception {
+        with 'List', 'List::Immutable';
+    }, undef, '... successfully composed roles together' );
+
+    package My::List2;
+    use Moose;
+
+    ::is( ::exception {
+        with 'List::Immutable', 'List';
+    }, undef, '... successfully composed roles together' );
+
+}
+
+{
+    my $coll = My::List1->new;
+    isa_ok($coll, 'My::List1');
+
+    ok($coll->does('List'), '... $coll does List');
+    ok($coll->does('List::Immutable'), '... $coll does List::Immutable');
+
+    ok($coll->is_empty, '... we have an empty collection');
+    is($coll->length, 0, '... we have a length of 1 for the collection');
+}
+
+{
+    my $coll = My::List2->new;
+    isa_ok($coll, 'My::List2');
+
+    ok($coll->does('List'), '... $coll does List');
+    ok($coll->does('List::Immutable'), '... $coll does List::Immutable');
+
+    ok($coll->is_empty, '... we have an empty collection');
+    is($coll->length, 0, '... we have a length of 1 for the collection');
+}
+
+{
+    my $coll = My::List1->new('::' => [ 1 .. 10 ]);
+    isa_ok($coll, 'My::List1');
+
+    ok($coll->does('List'), '... $coll does List');
+    ok($coll->does('List::Immutable'), '... $coll does List::Immutable');
+
+    ok(!$coll->is_empty, '... we do not have an empty collection');
+    is($coll->length, 10, '... we have a length of 10 for the collection');
+
+    is($coll->print, '1, 2, 3, 4, 5, 6, 7, 8, 9, 10', '... got the right printed value');
+
+    my $coll2 = $coll->apply(sub { $_[0] * $_[0] });
+    isa_ok($coll2, 'My::List1');
+
+    is($coll->print, '1, 2, 3, 4, 5, 6, 7, 8, 9, 10', '... original is still the same');
+    is($coll2->print, '1, 4, 9, 16, 25, 36, 49, 64, 81, 100', '... new collection is changed');
+}
+
+{
+    my $coll = My::List2->new('::' => [ 1 .. 10 ]);
+    isa_ok($coll, 'My::List2');
+
+    ok($coll->does('List'), '... $coll does List');
+    ok($coll->does('List::Immutable'), '... $coll does List::Immutable');
+
+    ok(!$coll->is_empty, '... we do not have an empty collection');
+    is($coll->length, 10, '... we have a length of 10 for the collection');
+
+    is($coll->print, '1, 2, 3, 4, 5, 6, 7, 8, 9, 10', '... got the right printed value');
+
+    my $coll2 = $coll->apply(sub { $_[0] * $_[0] });
+    isa_ok($coll2, 'My::List2');
+
+    is($coll->print, '1, 2, 3, 4, 5, 6, 7, 8, 9, 10', '... original is still the same');
+    is($coll2->print, '1, 4, 9, 16, 25, 36, 49, 64, 81, 100', '... new collection is changed');
+}
+
+done_testing;