Re: Exporter and subroutine circular dependencies between modules

--------------QhLs0K6PEYjWknw1iqBHJ4fY
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit

On 3/13/22 15:18, Shawn H Corey wrote:
> On 2022-03-13 18:08, Diab Jerius via module-authors wrote:
>>
>>     require Exporter;
>>     our @ISA    = qw( Exporter );
>>     our @EXPORT    = qw( foo )
>>
> I prefer this way:
> 
> # --------------------------------------
> # Exports
> use  Exporter      qw( import );
> our @EXPORT      = qw( foo );
> our @EXPORT_OK   = qw( );
> our %EXPORT_TAGS = (
>      all  => [ @EXPORT, @EXPORT_OK ],
> );
> 
> This automatically creates a tag for `:all`.


Thank you for the reply.  :-)


That approach does not solve the circular dependency issue:

2022-03-13 19:02:58 dpchrist@tinkywinky 
~/samba/dpchrist/sandbox/perl/Exporter-circular-use
$ cat /etc/debian_version ; uname -a ; perl -v | head -n 2
9.13
Linux tinkywinky 4.9.0-17-amd64 #1 SMP Debian 4.9.290-1 (2021-12-12) 
x86_64 GNU/Linux

This is perl 5, version 24, subversion 1 (v5.24.1) built for 
x86_64-linux-gnu-thread-multi

2022-03-13 19:03:22 dpchrist@tinkywinky 
~/samba/dpchrist/sandbox/perl/Exporter-circular-use
$ cvs diff
Index: Bar11.pm
===================================================================
RCS file: 
/var/local/cvs/dpchrist/sandbox/perl/Exporter-circular-use/Bar11.pm,v
retrieving revision 1.1
diff -r1.1 Bar11.pm
9,11c9,14
< require Exporter;
< our @ISA	= qw( Exporter );
< our @EXPORT	= qw( bar );
---
 > use Exporter	   qw( import );
 > our @EXPORT	 = qw( bar );
 > our @EXPORT_OK	 = qw();
 > our %EXPORT_TAGS = (
 >     all  => [ @EXPORT, @EXPORT_OK ],
 > );
Index: Foo11.pm
===================================================================
RCS file: 
/var/local/cvs/dpchrist/sandbox/perl/Exporter-circular-use/Foo11.pm,v
retrieving revision 1.1
diff -r1.1 Foo11.pm
9,11c9,15
< require Exporter;
< our @ISA	= qw( Exporter );
< our @EXPORT	= qw( foo );
---
 > use Exporter	   qw( import );
 > our @EXPORT	 = qw( foo );
 > our @EXPORT_OK   = qw();
 > our %EXPORT_TAGS = (
 >     all  => [ @EXPORT, @EXPORT_OK ],
 > );
 >

2022-03-13 19:03:24 dpchrist@tinkywinky 
~/samba/dpchrist/sandbox/perl/Exporter-circular-use
$ ./foo11
main=7
  foo=6
   bar=5
Undefined subroutine &Bar11::foo called at Bar11.pm line 25.


And, I have doubts about use'ing Exporter and importing Exporter::import().


But, you have reminded me that it is better style to export nothing by 
default (the demo script and modules used @EXPORT for brevity).


So, combining the ideas thus far:

BEGIN { our @EXPORT_OK = qw( foo ) }
use parent 'Exporter';


David



2022-03-13 19:06:46 dpchrist@tinkywinky 
~/samba/dpchrist/sandbox/perl/Exporter-circular-use
$ ./Exporter-circular-use.t
ok 1 - foo00
ok 2 - foo01
ok 3 - foo10
Undefined subroutine &Bar11::foo called at Bar11.pm line 22.
not ok 4 - foo11
#   Failed test 'foo11'
#   at ./Exporter-circular-use.t line 24.
#          got: 'main=7
#  foo=6
#   bar=5
# '
#     expected: 'main=7
#  foo=6
#   bar=5
#    foo=4
#     bar=3
#      foo=2
#       bar=1
# '
Undefined subroutine &Bar12::foo called at Bar12.pm line 23.
not ok 5 - foo12
#   Failed test 'foo12'
#   at ./Exporter-circular-use.t line 24.
#          got: 'main=7
#  foo=6
#   bar=5
# '
#     expected: 'main=7
#  foo=6
#   bar=5
#    foo=4
#     bar=3
#      foo=2
#       bar=1
# '
ok 6 - foo21
ok 7 - foo22
ok 8 - foo33
ok 9 - foo44
1..9
# Looks like you failed 2 tests of 9.
--------------QhLs0K6PEYjWknw1iqBHJ4fY
Content-Type: application/gzip;
 name="Exporter-circular-use-20220313-185149.tar.gz"
Content-Disposition: attachment;
 filename="Exporter-circular-use-20220313-185149.tar.gz"
Content-Transfer-Encoding: base64
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--------------QhLs0K6PEYjWknw1iqBHJ4fY--