find invalid lists

invalid_lists.pl

#!/usr/bin/perl

foreach $in ( @ARGV ) {
    next if( $in !~ /.+.adoc/ ) ;
    printf "\n:-| processing [$in] ...\n";
    open(IN, "<$in") || die "cant open file\n";
    $line = 0;
    $flag = 0;
    while( <IN> ) {
        ++ $line;
        chop;
        if($_ =~ /^\* .*/) {
            $flag = 1;
        } elsif ($_ eq "" || $_ eq "+") {
            $flag = 0;
        } elsif ($flag == 1 && $_ !~ /^ /) {
            printf "%4d : [%s]\n", $line, $_;
            $flag = 0;
        } else {
            $flag = 0;
        }
    }
    close(IN)
}