Re^2: announce missing modules

That's a great idea. I started to play with something similar and got the following for the anon function on the @INC array.

BEGIN {
        use 5.8.0;
        use vars qw(@missing);

        push @INC, sub { 
                my ($coderef, $filename) = @_;

                # Ignore non-modules.
                return undef unless ($filename =~ s/.pm$//);

                # Remember the module.
                $filename =~ s/\//::/g;
                push @missing, $filename;

                # Return a dummy file handle.
                open my $FH, '<', \'1;';
                $FH;
        };
}
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The INIT block is a great idea.

INIT {
        # Check and clean up.
        die "Missing modules.\n\tcpan -i ", join(' ',' @missing), "\n\
+n" if (@missing);
        pop @INC;
}
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The open my $FH, '<', \'1;'; is available in perl 5.8.8.

Is there a better way to deduce the module name than removing the .pm extension and replacing /s with ::? Will it work on non-UNIX platforms?

Popping the function off again seems like a good idea.

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Re^3: announce missing modules by Arif (Acolyte) on Feb 26, 2008 at 14:44 UTC
Just for the record, I found the flaw in this scheme. One of my included modules includes 'Storable', which tries to include 'Log::Agent'. If it fails then the 'Storable' module does something else. The above @INC scheme forces the user to install the conditional module. This shouldn't happen. So back to the old method (slightly refined to handle module versions and import lists) `{ our @missing = map +(m/^(\S+)/), grep !eval "use $_; 1", grep $_, split /\s\n\s/, " Storable File::Basename A::B wq(a b c) Foo::Bar CGI qw/:standard/ " and die "Please install CPAN modules: cpan -i @missing\n"; }` [download]	[reply] [d/l]

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Re^3: announce missing modules
by Arif (Acolyte) on Feb 26, 2008 at 14:44 UTC

So back to the old method (slightly refined to handle module versions and import lists)


{
   our @missing =
         map +(m/^(\S+)/),
         grep !eval "use $_; 1",
         grep $_,
         split /\s*\n\s*/, "
              Storable
              File::Basename
              A::B wq(a b c)
              Foo::Bar
              CGI qw/:standard/
        " and die "Please install CPAN modules: cpan -i @missing\n";
}
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