1Perl6::Export::Attrs(3)User Contributed Perl DocumentatioPnerl6::Export::Attrs(3)
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NAME

6       Perl6::Export::Attrs - The Perl 6 'is export(...)' trait as a Perl 5
7       attribute
8

VERSION

10       This document describes Perl6::Export::Attrs version 0.000006
11

SYNOPSIS

13           package Some::Module;
14           use Perl6::Export::Attrs;
15
16           # Export &foo by default, when explicitly requested,
17           # or when the ':ALL' export set is requested...
18
19           sub foo :Export(:DEFAULT) {
20               print "phooo!";
21           }
22
23
24           # Export &var by default, when explicitly requested,
25           # or when the ':bees', ':pubs', or ':ALL' export set is requested...
26           # the parens after 'is export' are like the parens of a qw(...)
27
28           sub bar :Export(:DEFAULT :bees :pubs) {
29               print "baaa!";
30           }
31
32
33           # Export &baz when explicitly requested
34           # or when the ':bees' or ':ALL' export set is requested...
35
36           sub baz :Export(:bees) {
37               print "baassss!";
38           }
39
40
41           # Always export &qux
42           # (no matter what else is explicitly or implicitly requested)
43
44           sub qux :Export(:MANDATORY) {
45               print "quuuuuuuuux!";
46           }
47
48
49           # Allow the constant $PI to be exported when requested...
50
51           use Readonly;
52           Readonly our $PI :Export => 355/113;
53
54
55           # Allow the variable $EPSILON to be always exported...
56
57           our $EPSILON :Export( :MANDATORY ) = 0.00001;
58
59
60           sub IMPORT {
61               # This subroutine is called when the module is used (as usual),
62               # but it is called after any export requests have been handled.
63           };
64

DESCRIPTION

66       Implements a Perl 5 native version of what the Perl 6 symbol export
67       mechanism will look like (with some unavoidable restrictions).
68
69       It's very straightforward:
70
71       ·   If you want a subroutine or package variable to be capable of being
72           exported (when explicitly requested in the "use" arguments), you
73           mark it with the ":Export" attribute.
74
75       ·   If you want a subroutine or package variable to be automatically
76           exported when the module is used (without specific overriding
77           arguments), you mark it with the ":Export(:DEFAULT)" attribute.
78
79       ·   If you want a subroutine or package variable to be automatically
80           exported when the module is used (even if the user specifies
81           overriding arguments), you mark it with the ":Export(:MANDATORY)"
82           attribute.
83
84       ·   If the subroutine or package variable should also be exported when
85           particular export groups are requested, you add the names of those
86           export groups to the attribute's argument list.
87
88       That's it.
89
90   "IMPORT" blocks
91       Perl 6 replaces the "import" subroutine with an "IMPORT" block. It's
92       analogous to a "BEGIN" or "END" block, except that it's executed every
93       time the corresponding module is "use"'d.
94
95       The "IMPORT" block is passed the argument list that was specified on
96       the "use" line that loaded the corresponding module, minus the
97       arguments that were used to specify exports.
98
99       Note that, due to limitations in Perl 5, the "IMPORT" block provided by
100       this module must be terminated by a semi-colon, unless it is the last
101       statement in the file.
102

DIAGNOSTICS

104       %s does not export: %s\nuse %s failed
105           You tried to import the specified subroutine or package variable,
106           but the module didn't export it. Often caused by a misspelling, or
107           forgetting to add an ":Export" attribute to the definition of the
108           subroutine or variable in question.
109
110       Bad tagset in :Export attribute at %s line %s: [%s]
111           You tried to import a collection of items via a tagset, but the
112           module didn't export any subroutines under that tagset. Is the
113           tagset name misspelled (maybe you forgot the colon?).
114
115       Can't export lexical %s variable at %s
116           The module can only export package variables. You applied the
117           ":Export" marker to a non-package variable (almost certainly to a
118           lexical). Change the variable's "my" declarator to an "our".
119
120       Can't export anonymous subroutine at %s
121           Although you can apply the ":Export" marker to an anonymous
122           subroutine, it rarely makes any sense to do so, since that
123           subroutine can't be exported without a name to export it as. Either
124           give the subroutine a name, or make sure it's aliased to a named
125           typeglob at compile-time (or, at least, before it's exported).
126

CONFIGURATION AND ENVIRONMENT

128       Perl6::Export::Attrs requires no configuration files or environment
129       variables.
130

DEPENDENCIES

132       This module requires the Attribute::Handlers module to handle the
133       attributes.
134

INCOMPATIBILITIES

136       This module cannot be used with the Memoize CPAN module, because
137       memoization replaces the original subroutine with a wrapper. Because
138       the ":Export" attribute is applied to the original (not the wrapper),
139       the memoized wrapper is not found by the exporter mechanism.
140

BUGS AND LIMITATIONS

142       No bugs have been reported.
143
144       Note that the module does not support exporting lexical variables,
145       since there is no way for the exporter mechanism to determine the name
146       of a lexical and hence to export it.
147
148       Nor does this module support the numerous addition export modes that
149       Perl 6 offers, such as export-as-lexical or export-as-state.
150
151       Please report any bugs or feature requests to
152       "bug-perl6-export-attrs@rt.cpan.org", or through the web interface at
153       <http://rt.cpan.org>.
154

AUTHOR

156       Damian Conway  "<DCONWAY@cpan.org>"
157
159       Copyright (c) 2005, Damian Conway "<DCONWAY@cpan.org>". All rights
160       reserved.
161
162       This module is free software; you can redistribute it and/or modify it
163       under the same terms as Perl itself.
164

DISCLAIMER OF WARRANTY

166       BECAUSE THIS SOFTWARE IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
167       FOR THE SOFTWARE, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT
168       WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER
169       PARTIES PROVIDE THE SOFTWARE "AS IS" WITHOUT WARRANTY OF ANY KIND,
170       EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
171       WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE
172       ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE SOFTWARE IS WITH
173       YOU. SHOULD THE SOFTWARE PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL
174       NECESSARY SERVICING, REPAIR, OR CORRECTION.
175
176       IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
177       WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
178       REDISTRIBUTE THE SOFTWARE AS PERMITTED BY THE ABOVE LICENCE, BE LIABLE
179       TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL, OR
180       CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE
181       SOFTWARE (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING
182       RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A
183       FAILURE OF THE SOFTWARE TO OPERATE WITH ANY OTHER SOFTWARE), EVEN IF
184       SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
185       DAMAGES.
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189perl v5.28.0                      2018-07-15           Perl6::Export::Attrs(3)
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