/*
* call-seq:
* array[index] -> obj or nil
* array[start, length] -> an_array or nil
* array[range] -> an_array or nil
* array.slice(index) -> obj or nil
* array.slice(start, length) -> an_array or nil
* array.slice(range) -> an_array or nil
*
* Element Reference---Returns the element at _index_,
* or returns a subarray starting at _start_ and
* continuing for _length_ elements, or returns a subarray
* specified by _range_.
* Negative indices count backward from the end of the
* array (-1 is the last element). Returns nil if the index
* (or starting index) are out of range.
*
* a = [ "a", "b", "c", "d", "e" ]
* a[2] + a[0] + a[1] #=> "cab"
* a[6] #=> nil
* a[1, 2] #=> [ "b", "c" ]
* a[1..3] #=> [ "b", "c", "d" ]
* a[4..7] #=> [ "e" ]
* a[6..10] #=> nil
* a[-3, 3] #=> [ "c", "d", "e" ]
* # special cases
* a[5] #=> nil
* a[5, 1] #=> []
* a[5..10] #=> []
*
*/
VALUE
rb_ary_aref(argc, argv, ary)
int argc;
VALUE *argv;
VALUE ary;
{
VALUE arg;
long beg, len;
if (argc == 2) {
if (SYMBOL_P(argv[0])) {
rb_raise(rb_eTypeError, "Symbol as array index");
}
beg = NUM2LONG(argv[0]);
len = NUM2LONG(argv[1]);
if (beg < 0) {
beg += RARRAY(ary)->len;
}
return rb_ary_subseq(ary, beg, len);
}
if (argc != 1) {
rb_scan_args(argc, argv, "11", 0, 0);
}
arg = argv[0];
/* special case - speeding up */
if (FIXNUM_P(arg)) {
return rb_ary_entry(ary, FIX2LONG(arg));
}
if (SYMBOL_P(arg)) {
rb_raise(rb_eTypeError, "Symbol as array index");
}
/* check if idx is Range */
switch (rb_range_beg_len(arg, &beg, &len, RARRAY(ary)->len, 0)) {
case Qfalse:
break;
case Qnil:
return Qnil;
default:
return rb_ary_subseq(ary, beg, len);
}
return rb_ary_entry(ary, NUM2LONG(arg));
}