[Koha-devel] Coding guidelines and Plack

[Galen Charlton]

Hi,

On Sun, Sep 22, 2013 at 10:40 PM, Marcel de Rooy
<M.de.Rooy at rijksmuseum.nl>wrote:

>  Should we add a PERL rule that prohibits defining lexical variables (my
> $var) at the outermost block (file level) ?
>
-1 for scripts -- it's not necessary, and doing anything to tempt folks to
use 'our' unnecessarily instead would be worse.  It's sufficient to ensure
that any subroutines inside the file aren't inappropriately accessing
file-level lexicals, and that's easy to test by verifying that the
following doesn't emit any warning messages:

perl -MCGI::Compile -e 'my $sub = CGI::Compile->compile($ARGV[0])' /path/to/
script.pl

How are we doing at the moment, for CGI scripts)?  Not badly, actually:

http://paste.koha-community.org/223

A provisional +1 for modules, where use of a package-level lexical is a
signal that state may be held on to inappropriately.  Running the
CGI::Compile test on *.pm files can point out the most egregious examples,
though.  As it turns out, C4 is doing less badly than I would have expected:

http://paste.koha-community.org/224

Even for modules, though usage of 'our' should be discouraged except for
VERSION and the like.

>  Is it also needed to move script subroutines to module level?
>
This would have to be handled carefully -- for example, to take it to an
extreme, a rule that "scripts cannot have subroutines" would be
problematic.  While there are undoubtedly plenty of routines that currently
live in scripts that could be generalized and moved into the Koha
namespace, sometimes a script really ought to have subroutines purely for
the sake of good organization, even if those subroutines have no utility
outside of that particular script.  There are plenty of legacy scripts that
never managed even plain old functional decomposition; and I would hate to
see anything that would (even inadvertently) discourage appropriate use of
local subroutines.

The key word is "appropriate" -- an internal subroutine that doesn't touch
variables that are not directly passed to it is fine, of course.

Regards,

Galen
-- 
Galen Charlton
Manager of Implementation
Equinox Software, Inc. / The Open Source Experts
email:  gmc at esilibrary.com
direct: +1 770-709-5581
cell:   +1 404-984-4366
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Supporting Koha and Evergreen: http://koha-community.org &
http://evergreen-ils.org
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