[]

/*
 *  call-seq:
 *     struct[symbol]    => anObject
 *     struct[fixnum]    => anObject 
 *  
 *  Attribute Reference---Returns the value of the instance variable
 *  named by <i>symbol</i>, or indexed (0..length-1) by
 *  <i>fixnum</i>. Will raise <code>NameError</code> if the named
 *  variable does not exist, or <code>IndexError</code> if the index is
 *  out of range.
 *     
 *     Customer = Struct.new(:name, :address, :zip)
 *     joe = Customer.new("Joe Smith", "123 Maple, Anytown NC", 12345)
 *     
 *     joe["name"]   #=> "Joe Smith"
 *     joe[:name]    #=> "Joe Smith"
 *     joe[0]        #=> "Joe Smith"
 */

VALUE
rb_struct_aref(s, idx)
    VALUE s, idx;
{
    long i;

    if (TYPE(idx) == T_STRING || TYPE(idx) == T_SYMBOL) {
        return rb_struct_aref_id(s, rb_to_id(idx));
    }

    i = NUM2LONG(idx);
    if (i < 0) i = RSTRUCT(s)->len + i;
    if (i < 0)
        rb_raise(rb_eIndexError, "offset %ld too small for struct(size:%ld)",
                 i, RSTRUCT(s)->len);
    if (RSTRUCT(s)->len <= i)
        rb_raise(rb_eIndexError, "offset %ld too large for struct(size:%ld)",
                 i, RSTRUCT(s)->len);
    return RSTRUCT(s)->ptr[i];
}