Hi Karl,
Every role has a similarly named method in the context class. This 
method returns the object that shall be bound to the role. E.g.:

¤   Shapes4ArrowsCtx >>Shape1
¤       ^data anyShape

The different shapes (and arrows) are found in a runtime dictionary that 
that is filled when the context class is instantiated:

¤   Shapes4ArrowsCtx >>bindRolesToObjects
¤       | messName |
¤       self class roleNames
¤           do: [:rNam |
¤               messName := rNam asString asSymbol.
¤               roleMap
¤                   at: messName
¤                   put: (self
¤                           perform: messName
¤                           ifNotUnderstood: [])].
¤       ^ roleMap

 The idea is that a programmer need to understand this, but should not 
need to understand the details of how it is done. (To see the details, 
look at these methods:
    Shapes4Env>>startArrowAnimation
    Shapes4ArrowsCtx  class>>executeInContext:
    Shapes4ArrowsCtx >>on:env:
    Shapes4ArrowsCtx >>bindRolesToObjects

I hope it answers your question.

The above is the current implementation.  I believe there is much room 
for simplification that should emerge when I write a tutorial. (Much 
better to rewrite the code than to try its complexities).

Chers
--Trygve


On 14.09.2008 16:25, Karl Ramberg wrote:
> Trygve Reenskaug wrote:
>> I just posted a new version of the BabyIDE report and Squeak image.
>> I post an image rather then a Montizello loadable file because it is 
>> just a demo.
>> I am working on a small application all done in BabyIDE.
>> I'll post a Monticello file (BabyIDE.alpha.0)as soon as this work is 
>> completed.
>
> I looked at the IDE and tried to find out how the different shapes got 
> selected in a sequence, but I got lost.
> Are the roles bound before the animation starts or how is it set up ?
>
> Karl
>
>

-- 

Trygve Reenskaug       mailto: trygver at ifi.uio.no

Morgedalsvn. 5A         http://heim.ifi.uio.no/~trygver

N-0378 Oslo               Tel: (+47) 22 49 57 27

Norway

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