# some simple binary operators

    sub plus  { $_[0] + $_[1] }
    sub times { $_[0] * $_[1] }

    # build n-ary operators from them

    *sum      = foldl_c( \&plus,  0 );
    *product  = foldl_c( \&times, 1 );

    # test them out

    say sum(1..10);       # 55
    say product(1..10);   # 3628800