On 24 Jan 2014, at 22:20, waldo kitty wrote:
> On 1/24/2014 3:18 PM, Ewald wrote:
>>
>> On 24 Jan 2014, at 21:20, waldo kitty wrote:
>>
>>> On 1/23/2014 2:18 PM, waldo kitty wrote:
>>>
>>> following up on this, how do i pass parameters to doThis and doThat?? do i
>>> have to use an intermediate pre_doThis and pre_doThat which handles the
>>> calls
>>> from centralControl and then calls doThis and doThat with the necessary
>>> parameters?
>>>
>>
>> Simply change the type:
>> Type
>> TProc = Procedure(aRecord: somerec);
>>
>> Then you can call whichProc (in centralControl) with your argument of choice.
>
> ahhh! that helps to explain what the compiler error was that i was seeing...
> so i may need two different types if each procedure called from
> centralControl has different parameters?
Basically yes (if you mean different parameter types/ different parameter order
-- the name in the procedure/function type is merely descriptive AFAIK). But if
you have many procedures, I'd go for a class:
TCentralControl = Class
Protected
Procedure Callback1; virtual; abstract;
Procedure Callback2(value: TSomeRec); virtual; abstract;
Function Callback3: Boolean; virtual abstract;
... and so on ...
Public
Procedure CentralControl(.....);
End;
Then simply inherit from this class a few times for the different scenario's
you want to cover.
> won't that cause a conflict if the parameters are not the same or are in
> different ordering or even if some procedure doesn't have parameters at all?
Yes, you would need a lot of parameters if you need a lot of callbacks. if this
is the case go for the OOP approach; it is perfectly suited for this kind of
thing.
--
Ewald
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