/*
 *  call-seq:
 *     dtable.as_exponent_of!(number)                ->  dtable
 *     dtable.as_exponent_of!(other)                 ->  dtable
 *  
 *  When argument is a number, this operation replaces each entry x of _dtable_ by _number_ ** x.
 *  When argument is a data array, this operation replaces each entry x of _dtable_
 *  by the corresponding entry in the _other_ data array raised to the power x.
 */ VALUE dtable_as_exponent_of_bang(VALUE ary, VALUE arg) {