/*
 * call-seq:
 *   row.each_pair { |column_value_array| block } -> row
 *
 * Iterate with column,value pairs.
 */
static VALUE
pgrow_each_pair(self)
    VALUE self;
{
    VALUE keys = pgrow_keys(self);
    int i;
    for (i = 0; i < RARRAY(keys)->len; ++i) {
        rb_yield(rb_assoc_new(rb_ary_entry(keys, i), rb_ary_entry(self, i)));
    }
    return self;
}