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
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
|
package Data::Stream::Bulk::Util;
BEGIN {
$Data::Stream::Bulk::Util::AUTHORITY = 'cpan:NUFFIN';
}
{
$Data::Stream::Bulk::Util::VERSION = '0.11';
}
use strict;
use warnings;
# ABSTRACT: Utility functions for L<Data::Stream::Bulk>
use Data::Stream::Bulk::Nil;
use Data::Stream::Bulk::Array;
use Scalar::Util qw(refaddr);
use namespace::clean;
use Sub::Exporter -setup => {
exports => [qw(nil bulk cat filter unique)],
};
# use constant nil => Data::Stream::Bulk::Nil->new;
sub nil () { Data::Stream::Bulk::Nil->new }
sub bulk (@) { return @_ ? Data::Stream::Bulk::Array->new( array => [ @_ ] ) : nil }
sub cat (@) { return @_ ? shift->cat(@_) : nil }
sub filter (&$) {
my ( $filter, $stream ) = @_;
$stream->filter($filter);
}
sub unique ($) {
my %seen;
shift->filter(sub { [ grep { !$seen{ref($_) ? refaddr($_) : $_}++ } @$_ ] }); # FIXME Hash::Util::FieldHash::Compat::id()?
}
__PACKAGE__;
=pod
=head1 NAME
Data::Stream::Bulk::Util - Utility functions for L<Data::Stream::Bulk>
=head1 VERSION
version 0.11
=head1 SYNOPSIS
use Data::Stream::Bulk::Util qw(array);
use namespace::clean;
# Wrap a list in L<Data::Stream::Bulk::Array>
return bulk(qw(foo bar gorch baz));
# return an empty resultset
return nil();
=head1 DESCRIPTION
This module exports convenience functions for use with L<Data::Stream::Bulk>.
=head1 EXPORTS
L<Sub::Exporter> is used to create the C<import> routine, and all of its
aliasing/currying goodness is of course supported.
=over 4
=item nil
Creates a new L<Data::Stream::Bulk::Nil> object.
Takes no arguments.
=item bulk @items
Creates a new L<Data::Stream::Bulk::Array> wrapping C<@items>.
=item cat @streams
Concatenate several streams together.
Returns C<nil> if no arguments are provided.
=item filter { ... } $stream
Calls C<filter> on $stream with the provided filter.
=item unique $stream
Filter the stream to remove duplicates.
Note that memory use may potentially scale to O(k) where k is the number of
distinct items, because this is implemented in terms of a seen hash.
In the future this will be optimized to be iterative for sorted streams.
References are keyed by their refaddr (see L<Hash::Util::FieldHash/id>).
=back
=head1 AUTHOR
Yuval Kogman <nothingmuch@woobling.org>
=head1 COPYRIGHT AND LICENSE
This software is copyright (c) 2012 by Yuval Kogman.
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.
=cut
__END__
|
