[Seaside] Dynamic typing in smalltalk

[andres]

Hi Alexandre,
			I guess you could try two approaches:

1. Just list the classes in a select, so that the first step is choosing 
the entry. Once you have this you just create the appropriate class.

2. Decouple the type of the object from the object itself (check also 
http://www.ksc.com/article3.htm). Thus PaperBibli would know an object 
(lets say PaperType) whose subclasses would be Book, Article, etc. When 
the user selects the type he wants you just set the object's type. The 
type class is the one that holds the type-specific information.

HTH,
         Andrés

Alexandre BP escribió:
> thank you for your replyI have a class named "PaperBibli" which keeps a list of bibliographic entries.Those entries are of different type: Article, Book, Conference,...Every type has its own fields such as: author,title,...
>  --> I created SubClasses of "PaperBibli" for each type so that when I instanciate an bibliographic entry I don't have lots of variables(fields) which are empty because not required in a particular type.The problem is that when I instanciate my bibliographic entry I still don't know of which type it is because the user tell me so by choosing in a scroll list.
> I hope that my explanation is clear
> 
> 
> 
> Date: Fri, 29 Oct 2010 12:24:22 -0400
> Subject: Re: [Seaside] Dynamic typing in smalltalk
> From: sean at monkeysnatchbanana.com
> To: seaside at lists.squeakfoundation.org
> 
> There are types in smalltalk. Each object has a type.
> That aside, what are you trying to accomplish with your example below?
> 
> On Fri, Oct 29, 2010 at 12:13 PM, Alexandre BP <abalonpe at ulb.ac.be> wrote:
> 
> 
> 
> 
> 
> 
> 
> Hello,
> I would like to know if it is possible to apply dynamic typing in smalltalk. For example, If I want to use polymorphism, it would be:	
>       var := Class new.	var := (SubClass1) message. 	var := (SubClass2) message.
> 
> Where message from SubClass1 is different then the one from SubClass2.Is there any solution for my problem? I know that there is no type in smalltalk but there is definitely a way to use polymorphism right?
> 
> Thank you in advance,Regardsalex 		 	   		  
> 
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