upto

/*
 *  call-seq:
 *     int.upto(limit) {|i| block }     => int
 *  
 *  Iterates <em>block</em>, passing in integer values from <i>int</i>
 *  up to and including <i>limit</i>.
 *     
 *     5.upto(10) { |i| print i, " " }
 *     
 *  <em>produces:</em>
 *     
 *     5 6 7 8 9 10
 */

static VALUE
int_upto(from, to)
    VALUE from, to;
{
    if (FIXNUM_P(from) && FIXNUM_P(to)) {
        long i, end;

        end = FIX2LONG(to);
        for (i = FIX2LONG(from); i <= end; i++) {
            rb_yield(LONG2FIX(i));
        }
    }
    else {
        VALUE i = from, c;

        while (!(c = rb_funcall(i, '>', 1, to))) {
            rb_yield(i);
            i = rb_funcall(i, '+', 1, INT2FIX(1));
        }
        if (NIL_P(c)) rb_cmperr(i, to);
    }
    return from;
}