1Export::Attrs(3pm)    User Contributed Perl Documentation   Export::Attrs(3pm)
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NAME

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

VERSION

9       This document describes Export::Attrs version v0.1.0
10

SYNOPSIS

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

DESCRIPTION

65       NOTE: This module is a fork of Perl6::Export::Attrs created to restore
66       compatibility with Perl6::Export::Attrs version 0.0.3.
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68       Implements a Perl 5 native version of what the Perl 6 symbol export
69       mechanism will look like (with some unavoidable restrictions).
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71       It's very straightforward:
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73       •   If you want a subroutine or package variable to be capable of being
74           exported (when explicitly requested in the "use" arguments), you
75           mark it with the ":Export" attribute.
76
77       •   If you want a subroutine or package variable to be automatically
78           exported when the module is used (without specific overriding
79           arguments), you mark it with the ":Export(:DEFAULT)" attribute.
80
81       •   If you want a subroutine or package variable to be automatically
82           exported when the module is used (even if the user specifies
83           overriding arguments), you mark it with the ":Export(:MANDATORY)"
84           attribute.
85
86       •   If the subroutine or package variable should also be exported when
87           particular export groups are requested, you add the names of those
88           export groups to the attribute's argument list.
89
90       That's it.
91
92   "IMPORT" blocks
93       Perl 6 replaces the "import" subroutine with an "IMPORT" block. It's
94       analogous to a "BEGIN" or "END" block, except that it's executed every
95       time the corresponding module is "use"'d.
96
97       The "IMPORT" block is passed the argument list that was specified on
98       the "use" line that loaded the corresponding module, minus the
99       arguments that were used to specify exports.
100
101       Note that, due to limitations in Perl 5, the "IMPORT" block provided by
102       this module must be terminated by a semi-colon, unless it is the last
103       statement in the file.
104

DIAGNOSTICS

106       %s does not export: %s\nuse %s failed
107           You tried to import the specified subroutine or package variable,
108           but the module didn't export it. Often caused by a misspelling, or
109           forgetting to add an ":Export" attribute to the definition of the
110           subroutine or variable in question.
111
112       Bad tagset in :Export attribute at %s line %s: [%s]
113           You tried to import a collection of items via a tagset, but the
114           module didn't export any subroutines under that tagset. Is the
115           tagset name misspelled (maybe you forgot the colon?).
116
117       Can't export lexical %s variable at %s
118           The module can only export package variables. You applied the
119           ":Export" marker to a non-package variable (almost certainly to a
120           lexical). Change the variable's "my" declarator to an "our".
121
122       Can't export anonymous subroutine at %s
123           Although you can apply the ":Export" marker to an anonymous
124           subroutine, it rarely makes any sense to do so, since that
125           subroutine can't be exported without a name to export it as. Either
126           give the subroutine a name, or make sure it's aliased to a named
127           typeglob at compile-time (or, at least, before it's exported).
128

CONFIGURATION AND ENVIRONMENT

130       Export::Attrs requires no configuration files or environment variables.
131

DEPENDENCIES

133       This module requires the Attribute::Handlers module to handle the
134       attributes.
135

INCOMPATIBILITIES

137       This module cannot be used with the Memoize CPAN module, because
138       memoization replaces the original subroutine with a wrapper. Because
139       the ":Export" attribute is applied to the original (not the wrapper),
140       the memoized wrapper is not found by the exporter mechanism.
141

LIMITATIONS

143       Note that the module does not support exporting lexical variables,
144       since there is no way for the exporter mechanism to determine the name
145       of a lexical and hence to export it.
146
147       Nor does this module support the numerous addition export modes that
148       Perl 6 offers, such as export-as-lexical or export-as-state.
149

SUPPORT

151   Bugs / Feature Requests
152       Please report any bugs or feature requests through the issue tracker at
153       <https://github.com/powerman/perl-Export-Attrs/issues>.  You will be
154       notified automatically of any progress on your issue.
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156   Source Code
157       This is open source software. The code repository is available for
158       public review and contribution under the terms of the license.  Feel
159       free to fork the repository and submit pull requests.
160
161       <https://github.com/powerman/perl-Export-Attrs>
162
163           git clone https://github.com/powerman/perl-Export-Attrs.git
164
165   Resources
166       •   MetaCPAN Search
167
168           <https://metacpan.org/search?q=Export-Attrs>
169
170       •   CPAN Ratings
171
172           <http://cpanratings.perl.org/dist/Export-Attrs>
173
174       •   AnnoCPAN: Annotated CPAN documentation
175
176           <http://annocpan.org/dist/Export-Attrs>
177
178       •   CPAN Testers Matrix
179
180           <http://matrix.cpantesters.org/?dist=Export-Attrs>
181
182       •   CPANTS: A CPAN Testing Service (Kwalitee)
183
184           <http://cpants.cpanauthors.org/dist/Export-Attrs>
185

AUTHOR

187       Alex Efros <powerman@cpan.org>
188
189       Damian Conway <DCONWAY@cpan.org>
190
192       This software is Copyright (c) 2016 by Alex Efros <powerman@cpan.org>.
193
194       Copyright (c) 2005,2015 Damian Conway <DCONWAY@cpan.org>. All rights
195       reserved.
196
197       This module is free software; you can redistribute it and/or modify it
198       under the same terms as Perl itself.
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202perl v5.34.0                      2022-01-21                Export::Attrs(3pm)
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