Where is #932 implemented in PL1?

932   Need to break Demeter's law to access ADO field value by name

Where is this implemented and what is Demeter's Law. (I know in
ancient mythology she was pissed off at Hades for abducting her
daughter. Anything to do with this?)

Regards

Costas

Hi Costas

IIRC the law of Demeter says  in good OO design that in response to a
message -M -an object - Obj -should only send messages to the following 4
objects -
    Obj (i.e. self)
    Objects  directly accesible from Obj ( i.e. refered to by attributes of
Obj)
    Objects sent as arguments to M
    Objects created  as a result of M

The claimed advantages of this is that each objects interface is kept as
small as possible and that minimal disruption is caused when any object in
the system is changed.

Hope that helps

David

"Costas" <[hidden email]> wrote in message
news:[hidden email]...
> 932   Need to break Demeter's law to access ADO field value by name
>
> Where is this implemented and what is Demeter's Law. (I know in
> ancient mythology she was pissed off at Hades for abducting her
> daughter. Anything to do with this?)
>
> Regards
>
> Costas

Costas,

> Where is this implemented

Looks like it's the same as in Blair's earlier reply to you in the newsgroup
(10/5/2002 11:01). ADOCollection>>at: and ADOCollection>>item: are now part
of the standard image.

>                          and what is Demeter's Law. (I know in
> ancient mythology she was pissed off at Hades for abducting her
> daughter. Anything to do with this?)

See the following (the c2 wiki is probably the most interesting)

http://www.ccs.neu.edu/home/lieber/LoD.html
http://www.enteract.com/~bradapp/docs/demeter-intro.html
http://c2.com/cgi/wiki?LawOfDemeter

--
Ian
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