my @sources = grep /\.c$/, glob '*'; # get only the files ending in .c from a listing of the working directory

my @objects = map s/\.c$/\.o/, @sources; # get the list of object files that a c compiler would make by default from the files now in @sources

my @virgins = map { my $c = $_;
                    $c =~ s/\.o$/\.c/;
                    system "cc $c";
                    $c } grep !(-f), @objects;
                # find and compile the uncompiled sources