sub warn_from {
    my ($line,$file,$text) =@_;

    eval <<"__CODE__";
#line $line $file;
warn \$text;
__CODE__
}


warn_from(42,'captain.pl', "I say what!");

##</code><code>##

/usr/bin/perl -w /home/lanx/warn_new.pl 
I say what! at captain.pl; line 42.