Re: [Caml-list] Question about objects and method overriding

[Tom Ridge <tom.j.ridge+list@googlemail.com>]

Thanks, that is what I feared. Added as feature request:

http://caml.inria.fr/mantis/view.php?id=6314

On 2 February 2014 12:43, Jacques Garrigue <garrigue@math.nagoya-u.ac.jp> wrote:
> On 2014/02/02 20:55, Tom Ridge wrote:
>
>> Dear caml-list,
>>
>> With records, one can functionally update a field e.g. as
>>
>> { r with some_field=new_value }
>>
>> And new_value may, of course, be a function.
>>
>> With objects, is there similar functionality? e.g. can I write something like
>>
>> {{ myobj with method some_method=new_method }}
>>
>> ?
>>
>> Of course, I could copy the methods from myobj explicitly into a new
>> object (and set some_method to new_method), but I might not know all
>> the methods available on myobj, and even if I do this becomes
>> textually extremely verbose.
>>
>> Of course, new_method cannot directly refer to self etc. Basically I
>> am using objects in a similar way to records, and would like to use
>> this functional record update feature.
>>
>> Thanks
>>
>> Tom
>
>
> You can copy an object updating a value field, not a method field:
>
> class point (x:int) = object val x = x method get = x method bump dx = {< x = x+dx >} end
>
> You can use this for methods too, by having them call a function value field.
> However, this kind of update is only available inside methods, which requires some thinking
> when designing your code.
>
> I agree that what you suggest would be nice to have.
> There is no majore technical difficulty, but there would be some overhead.
>
>         Jacques Garrigue