GetOpt::Long usage style

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原文链接：https://www.perlmonks.org/?node_id=241367

by demerphq Log inCreate a new user The Monastery Gates Seekers of Perl Wisdom Meditations Cool Uses For Perl Obfuscation Tutorials Poetry Reviews Perl News Donate Recent Threads Newest Nodes Super Search PerlMonks Discussion What’s New
on Mar 08, 2003 at 11:15 UTC ( #241367=perlmeditation: print w/replies, xml ) Need Help??
Getopt::Long is a basic part of the Perl toolset. However one minor nit that Ive had up to now is that specifying the arguments and their destinations, along with defaults seemed a bit clumsy under strict. Take an example from the documentation

use GetOpt::Long;
my $verbose = '';   # option variable with default value (false)
my $all = '';       # option variable with default value (false)
GetOptions ('verbose' => \$verbose, 'all' => \$all);

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To me this is inelegant. I have two “declarations” about a variable in separate locations, one the real declaration along with the default value, and the other the association of the option name (which may be different from the variable name) to the variable. If I want to rename a variable for clarity later on I have to change two items. Now perhaps this is blindingly obvious to the rest of you but I just realized that you can instead write this

use GetOpt::Long;
#Adjust bractes and commas to taste
GetOptions ('verbose' => \(my $verbose = ''),   'all'     => \(my $all     = ''),);

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Which to me seems preferable. Everything is in one place. It says “this variable normally comes from outside”, it puts the declaration of the variable next to the declaration of the option handling it is associated with, and it provides a way to document the whole lot in one place if you need to.

Any thoughts?

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