* array.c (rb_check_array_type): new function: return an array
  (convert if possible), or nil.

* string.c (rb_check_string_type): new function: return a string
  (convert if possible), or nil.

* numeric.c (rb_dbl_cmp): returns nil if values are not
  comparable.

* numeric.c (fix_cmp,flo_cmp): use rb_num_coerce_cmp()

* bignum.c (rb_big_cmp): ditto.

* numeric.c (rb_num_coerce_cmp): new coercing function for "<=>",
  which does not raise TypeError.

* numeric.c (do_coerce): can be supress exception now.

* object.c (rb_mod_cmp): should return nil for non class/module
  objects.

* re.c (rb_reg_eqq): return false if the argument is not a
  string.  now returns boolean value.

* class.c (rb_include_module): argument should be T_MODULE, not
  T_class, nor T_ICLASS.

* eval.c (is_defined): "defined?" should return "assignment" for
  attribute assignment (e.g. a.foo=b) and indexed assignment
  (e.g. a[2] = 44).

* parse.y (aryset): use NODE_ATTRASGN.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@3169 b2dd03c8-39d4-4d8f-98ff-823fe69b080e