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perlmodulecpan

Why are Perl modules case sensitive?

Although I haven't seen any modules with same name but with different cases, but just for curiosity, I was trying to install Log::Log4perl and during installation I misspelled it 'Perl' in place of 'perl':

% cpan -i Log::Log4Perl 
Cannot install Log::Log4Perl, don't know what it is.

When I used correct name then things went well:

% cpan -i Log::Log4perl

Same names but different cases can create conflicts. Is there any specific reason behind that?

Solution

  • Because

    use Foo::Bar;

    would be ambiguous on case-sensitive file systems (Foo/Bar.pm? foo/bar.pm? FOO/BAR.pm? Foo/Bar.PM? etc), and it would require traversing the directory's contents to find the file's name. (Up to 9 directories per element of @INC would need traversing for Foo::Bar.)