[DUG] Why use a set when a string will work OK (and less code)?

[Sean Cross]

Because then you are forever checking status with code like


If Status = 'Active' then  ..
Else if Status = 'Pending'...

So you end up using consts.  And you still have the problem that your Status may end up as '' or 'Ative' or 'as323'

And you can't use case statements.

If status is purely informational, then using a string is fine.  Once you start checking it and acting on it, then string based code becomes increasingly ugly.

What I do is something like:

TMyStatus = (Active, Pending, Ended, Paused, Deleted, Suspended);
StatusMeanings = array[TMyStatus] of string = ('Active', 'Pending', 'Ended', 'Paused', 'Deleted', 'Suspended');
...
ShowMessage(StatusMeanings[Status]);

Regards

Sean Cross
IT Systems Development Manager

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> -----Original Message-----
> From: delphi-bounces at delphi.org.nz [mailto:delphi-
> bounces at delphi.org.nz] On Behalf Of Nick
> Sent: Thursday, 10 May 2007 10:49 a.m.
> To: NZ Borland Developers Group - Delphi List
> Subject: [DUG] Why use a set when a string will work OK (and less
> code)?
>
> Why use a set when string work ok? (and I think it's a set)
> Question: I have seen this quite a bit and apparently it's "good
> practice" however to me it seems like more work.
> Example
>
> Whats the point in doing this
> MyStatus = (Active, Pending, Ended, Paused, Deleted, Suspended););
> type
>   Something = class
>   name : string;
>   status : MyStatus;
> end;
>
> then example on create or something
>   status := Active;
>
> (yes, missed out lots of steps :P)
> and now if I want to show the status, I have to do something like..
> If status = MyStatus(Active) then showmessage('Active');
> If status = MyStatus(Pending) then showmessage('Pending');  etc
>
> Why go though all that hassle when just doing this is fine
>  status : string;
>  status := 'Active'
>  showmessage(status);
>
> so instead of using "MyStatus" types I just use a string - this means
> when I want to output the status to the user I don't have to try and
> convert it to string first.
> So, why do it?
>
> Hmmmm
> Nick
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