[fpc-pascal] Can property setters be procedures only?

[Michael Van Canneyt]

On Wed, 6 Feb 2013, Frank Church wrote:

> On 6 February 2013 09:07, Michael Van Canneyt <michael at freepascal.org> wrote:
>>
>>
>> On Wed, 6 Feb 2013, Frank Church wrote:
>>
>>> When I try to set a property using a function I get the error:
>>>
>>> form001.pas(28,64) Error: Illegal symbol for property access
>>> form001.pas(34,1) Fatal: There were 1 errors compiling module, stopping
>>>
>>> Is there something about properties that prevent them from being set
>>> by a function?
>>
>>
>> Yes, the absence of a result.
>> Results sometimes require special handling (strings etc).
>>
>>
>>> I can call a function to set that property, but I wonder why a setter
>>> can't be a function?
>>
>>
>> Because there is no result.
>>
>> Where is the result in
>>  MyControl.Top:=3;
>> ?
>>
>
> What I'm thinking of is when there is an error and the sender has to
> be notified?

In the case of properties this can only be done with exceptions.

> I am thinking of a case where it would be undesirable to raise an
> exception that would stop the flow of the program
> Would it be better to have some kind of exception handler or calling
> some kind of function that would return an error code would be better?

You should use exceptions.

Michael.