There is a2p, which converts awk scripts to Perl code. In your case, it creates the following program:

#!/opt/perl-5.18/bin/perl
eval 'exec /opt/perl-5.18/bin/perl -S $0 ${1+"$@"}'
    if $running_under_some_shell;
                        # this emulates #! processing on NIH machines.
                        # (remove #! line above if indigestible)

eval '$'.$1.'$2;' while $ARGV[0] =~ /^([A-Za-z_0-9]+=)(.*)/ && shift;
                        # process any FOO=bar switches

$, = ' ';               # set output field separator
$\ = "\n";              # set output record separator

while (<>) {
    ($Fld1,$Fld2,$Fld3,$Fld4) = split(' ', $_, -1);
    print $Fld4;
}
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Most of that is just setting up explicitly what perl has as defaults anyway. The interesting part (for you) is the while loop. Either use that in a oneliner or keep the whole thing as a Perl program.