How about this (as an alternative to the File::Find answers)?

#!/usr/bin/perl
use strict;
use warnings;
use Data::Dumper;
use constant RECURSIVE => 1;

sub find_files_in_dir {
    my ($dir,@extensions) = @_;

    my $match = join('|',@extensions);

    opendir(DIR,$dir) or die $!;
    my @files = 
        map {
            $_->{name} . '.' . $_->{extension};
        }
        grep {
            $_->{extension} =~ m/\A(?:$match)\Z/o if $_;
        }
        map {
            my $file_with_dir = $dir . '/' . $_;
            if( -f $file_with_dir ){
              { name => $1, extension => $2} if m/\A(.*?)\.(.*?)\Z/o;
            }elsif( RECURSIVE && -d $file_with_dir ){
              map {
                {name => $1, extension => $2} if m/\A(.*?)\.(.*?)\Z/o;
              } find_files_in_dir($file_with_dir , @extensions );
            }
        } grep { !m/\A(?:\.+)\Z/o } readdir(DIR);
    closedir(DIR);

    return @files;
}

my @files = find_files_in_dir(
    '.',
    qw( html pl pm )
);
print Dumper(\@files),"\n";
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Update: Added recursion