What is the real purpose of the $VERSION variable in Perl? -

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i've read it's considered practice include $version number in of perl scripts, never understood purpose.

what gain including version number in script?

only modules, , pushed cpan benefit specifying $version. there's not use in script except use familiar name rather inventing new 1 if want script's version accessible.

primary uses:

  • cpan uses version of distribution, allowing index different versions of same distribution.

  • cpan , cpanm uses check if installed module of sufficiently high level meet required minimum version of dependency.

as brian d foy mentioned, can checked use foo 1.23;, people avoid in favour of specifying required versions of dependencies in distribution's meta file. allows cpan , cpanm update dependency if needed (where use using use foo 1.23; cause installation fail during testing). due lack of use of feature, it's hardly primary use.


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