[Pharo-dev] About Spec second interpretation loop between Adapter and specific back end

May 8, 2014

      Hi Ben

When igor integrated his textEditor with Spec we saw that the relation 
between
a model and its adapter is not direct but via another interpretation.
For example

MorphicButtonAdapter class>> defaultSpec

^ {#PluggableButtonMorph.
             #color:. Color white.
                 #on:getState:action:label:menu:.     #model. #state. 
#action. #label. nil.
             #getEnabledSelector:.                 #enabled.
             #getMenuSelector:.                #menu:.
             #hResizing:.                         #spaceFill.
             #vResizing:.                         #spaceFill.
             #borderWidth:.                        #(model borderWidth).
             #borderColor:.                        #(model borderColor).
             #askBeforeChanging:.                #(model askBeforeChanging).
             #setBalloonText:.                    { #model . #help}.
             #dragEnabled:.                        #(model dragEnabled).
             #dropEnabled:.                        #(model dropEnabled).
             #eventHandler:.                    {    #EventHandler. 
#on:send:to:. #keyStroke.    #keyStroke:fromMorph:. #model    }}

We do not understand why it is needed. Because the adapter is specific 
to a platform and to a model so
For example why do we have

     #borderWidth:.                        #(model borderWidth).

while we could have
MorphiButtonAdapter>>borderWitdh

      ^ self model borderWidth

Having this extra interpretation loop
     - is costly
     - blur the API of the class (as a programmer I do not see the exact 
API) the cross navigation gets
     confused.
     - makes the code more complex to understand
for example
     #eventHandler:.                    {    #EventHandler. 
#on:send:to:. #keyStroke.    #keyStroke:fromMorph:. #model    }}

In addition is not a kind of static meta description so we will always 
need interpretation.

So I would really like to see if we can avoid this second interpretation.

Stef

[Pharo-dev] About Spec second interpretation loop between Adapter and specific back end

stepharo