partition

/*
 *  call-seq:
 *     enum.partition {| obj | block }  => [ true_array, false_array ]
 *  
 *  Returns two arrays, the first containing the elements of
 *  <i>enum</i> for which the block evaluates to true, the second
 *  containing the rest.
 *     
 *     (1..6).partition {|i| (i&1).zero?}   #=> [[2, 4, 6], [1, 3, 5]]
 *     
 */

static VALUE
enum_partition(obj)
    VALUE obj;
{
    VALUE ary[2];

    ary[0] = rb_ary_new();
    ary[1] = rb_ary_new();
    rb_iterate(rb_each, obj, partition_i, (VALUE)ary);

    return rb_assoc_new(ary[0], ary[1]);
}