[Python-checkins] CVS: python/dist/src/Misc NEWS,1.100,1.101

[Guido van Rossum]

Update of /cvsroot/python/python/dist/src/Misc
In directory usw-pr-cvs1:/tmp/cvs-serv25112

Modified Files:
	NEWS 
Log Message:
- Add note about complex numbers.

- Changed description of rich comparisons to emphasize that < and >
  (etc.) are each other's reflection.  Also use this word in the note
  about the demise of __rcmp__.


Index: NEWS
===================================================================
RCS file: /cvsroot/python/python/dist/src/Misc/NEWS,v
retrieving revision 1.100
retrieving revision 1.101
diff -C2 -r1.100 -r1.101
*** NEWS	2001/01/17 17:09:53	1.100
--- NEWS	2001/01/18 14:28:08	1.101
***************
*** 30,40 ****
    Classes can overload individual comparison operators by defining one
    or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
!   __ge__.  There are no explicit "reversed argument" versions of
!   these; instead, __lt__ and __gt__ are each other's reverse, likewise
!   for__le__ and __ge__; __eq__ and __ne__ are their own reverse
!   (similar at the C level).  No other implications are made; in
!   particular, Python does not assume that == is the inverse of !=, or
!   that < is the inverse of >=.  This makes it possible to define types
!   with partial orderings.
  
    Classes or types that want to implement (in)equality tests but not
--- 30,40 ----
    Classes can overload individual comparison operators by defining one
    or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
!   __ge__.  There are no explicit "reflected argument" versions of
!   these; instead, __lt__ and __gt__ are each other's reflection,
!   likewise for__le__ and __ge__; __eq__ and __ne__ are their own
!   reflection (similar at the C level).  No other implications are
!   made; in particular, Python does not assume that == is the Boolean
!   inverse of !=, or that < is the Boolean inverse of >=.  This makes
!   it possible to define types with partial orderings.
  
    Classes or types that want to implement (in)equality tests but not
***************
*** 42,46 ****
    and !=, and raise an error for the ordering operators.
  
!   It is possible to define types whose comparison results are not
    Boolean; e.g. a matrix type might want to return a matrix of bits
    for A < B, giving elementwise comparisons.  Such types should ensure
--- 42,46 ----
    and !=, and raise an error for the ordering operators.
  
!   It is possible to define types whose rich comparison results are not
    Boolean; e.g. a matrix type might want to return a matrix of bits
    for A < B, giving elementwise comparisons.  Such types should ensure
***************
*** 49,52 ****
--- 49,59 ----
    at the C level) to always raise an exception.
  
+ - Complex numbers use rich comparisons to define == and != but raise
+   an exception for <, <=, > and >=.  Unfortunately, this also means
+   that cmp() of two complex numbers raises an exception when the two
+   numbers differ.  Since it is not mathematically meaningful to compare
+   complex numbers except for equality, I hope that this doesn't break
+   too much code.
+ 
  - Functions and methods now support getting and setting arbitrarily
    named attributes (PEP 232).  Functions have a new __dict__
***************
*** 114,118 ****
    is considered an improvement.  Also note that __rcmp__ is no longer
    supported -- instead of calling __rcmp__, __cmp__ is called with
!   reversed arguments.
  
  - In connection with the coercion changes, a new built-in singleton
--- 121,125 ----
    is considered an improvement.  Also note that __rcmp__ is no longer
    supported -- instead of calling __rcmp__, __cmp__ is called with
!   reflected arguments.
  
  - In connection with the coercion changes, a new built-in singleton