1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
|
package Catmandu::Fix::Bind::maybe;
use Catmandu::Sane;
our $VERSION = '1.2024';
use Moo;
use Scalar::Util qw(reftype);
use namespace::clean;
with 'Catmandu::Fix::Bind';
# Copied from hiratara's Data::Monad::Maybe
sub just {
my ($self, @values) = @_;
bless [@values], __PACKAGE__;
}
sub nothing {
my ($self) = @_;
bless \(my $d = undef), __PACKAGE__;
}
sub is_nothing {
my ($self, $mvar) = @_;
reftype $mvar ne 'ARRAY';
}
sub value {
my ($self, $mvar) = @_;
if ($self->is_nothing($mvar)) {
{};
}
else {
$mvar->[0];
}
}
sub unit {
my ($self, $data) = @_;
$self->just($data);
}
sub bind {
my ($self, $mvar, $func) = @_;
if ($self->is_nothing($mvar)) {
return $self->nothing;
}
my $res;
eval {$res = $func->($self->value($mvar));};
if ($@) {
return $self->nothing;
}
if (defined $res) {
return $self->just($res);
}
else {
return $self->nothing;
}
}
sub result {
my ($self, $mvar) = @_;
$self->value($mvar);
}
1;
__END__
=pod
=head1 NAME
Catmandu::Fix::Bind::maybe - a binder that skips fixes if one returns undef or dies
=head1 SYNOPSIS
do maybe()
foo()
return_undef() # rest will be ignored
bar()
end
=head1 DESCRIPTION
The maybe binder computes all the Fix function and ignores fixes that throw exceptions.
=head1 SEE ALSO
L<Catmandu::Fix::Bind>
=cut
|
