/*
 *  call-seq:
 *     enum.zip(arg, ...)                   => array
 *     enum.zip(arg, ...) {|arr| block }    => nil
 *  
 *  Converts any arguments to arrays, then merges elements of
 *  <i>enum</i> with corresponding elements from each argument. This
 *  generates a sequence of <code>enum#size</code> <em>n</em>-element
 *  arrays, where <em>n</em> is one more that the count of arguments. If
 *  the size of any argument is less than <code>enum#size</code>,
 *  <code>nil</code> values are supplied. If a block given, it is
 *  invoked for each output array, otherwise an array of arrays is
 *  returned.
 *     
 *     a = [ 4, 5, 6 ]
 *     b = [ 7, 8, 9 ]
 *     
 *     (1..3).zip(a, b)      #=> [[1, 4, 7], [2, 5, 8], [3, 6, 9]]
 *     "cat\ndog".zip([1])   #=> [["cat\n", 1], ["dog", nil]]
 *     (1..3).zip            #=> [[1], [2], [3]]
 *     
 */

static VALUE
enum_zip(argc, argv, obj)
    int argc;
    VALUE *argv;
    VALUE obj;
{
    int i;
    VALUE result;
    VALUE memo[3];

    for (i=0; i<argc; i++) {
        argv[i] = rb_convert_type(argv[i], T_ARRAY, "Array", "to_a");
    }
    result = rb_block_given_p() ? Qnil : rb_ary_new();
    memo[0] = result;
    memo[1] = rb_ary_new4(argc, argv);
    memo[2] = 0;
    rb_iterate(rb_each, obj, zip_i, (VALUE)memo);

    return result;
}