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bug#14792: Error in manual "(guile-2) Object Properties"
From: |
David Kastrup |
Subject: |
bug#14792: Error in manual "(guile-2) Object Properties" |
Date: |
Tue, 16 Jul 2013 22:01:18 +0200 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/24.3.50 (gnu/linux) |
Mark H Weaver <address@hidden> writes:
> David Kastrup <address@hidden> writes:
>
>> Mark H Weaver <address@hidden> writes:
>>
>>> David Kastrup <address@hidden> writes:
>>>
>>>> Mark H Weaver <address@hidden> writes:
>>>>
>>>> object identity is checked by eq? and is conceptually different from
>>>> value equality.
>>>
>>> The Scheme standards don't support your view. The _only_ difference
>>> between 'eq?' and 'eqv?' is that 'eqv?' is well-defined on numbers and
>>> characters, whereas 'eq?' is unspecified for those types.
>>
>> And why would that be if numbers were proper objects? The difference is
>> _exactly_ there because they aren't.
>
> I don't know what you mean by "proper objects". I guess maybe you mean
> "objects with identity".
>
>>> Numbers and characters do not have any notion of "object identity",
>>> apart from operational equivalence.
>>
>> Which is why it does not make a lot of sense to assign "object
>> properties" to them.
>
> I understand that in the dominant "object oriented" programming
> communities of today, the word "object" usually implies mutability and
> identity, but the Scheme standards use the term differently.
>
> In the Scheme standards, the word "object" is synonymous with "value".
> R5RS section 1.1 states "Types are associated with values (also called
> objects) rather than with variables." Furthermore, R6RS consistently
> calls numbers "objects", even though they lack "object identity" in the
> sense that you mean.
Well, eq?/eqv? are an inheritance from Lisp's eq/eql. If there is no
clear conceptual difference any more, it would seem like a mistake to
keep two different operators around.
--
David Kastrup
- bug#14792: Error in manual "(guile-2) Object Properties", David Kastrup, 2013/07/04
- bug#14792: Error in manual "(guile-2) Object Properties", Mark H Weaver, 2013/07/05
- bug#14792: Error in manual "(guile-2) Object Properties", Ludovic Courtès, 2013/07/06
- bug#14792: Error in manual "(guile-2) Object Properties", Mark H Weaver, 2013/07/16
- bug#14792: Error in manual "(guile-2) Object Properties", David Kastrup, 2013/07/16
- bug#14792: Error in manual "(guile-2) Object Properties", Mark H Weaver, 2013/07/16
- bug#14792: Error in manual "(guile-2) Object Properties", David Kastrup, 2013/07/16
- bug#14792: Error in manual "(guile-2) Object Properties", Mark H Weaver, 2013/07/16
- bug#14792: Error in manual "(guile-2) Object Properties",
David Kastrup <=
- bug#14792: Error in manual "(guile-2) Object Properties", Ludovic Courtès, 2013/07/16
bug#14792: Actually, this discussion is moot, David Kastrup, 2013/07/27