^ childrenWidget ifNil: [childrenWidget := (PRComponent named: 'children')

componentClass: PRChildrenWidget;

write: 2

using: PRChildrenWidget descriptionLevel;

write: true

using: PRChildrenWidget descriptionExpand;

yourself

]

and:

PRChildrenWidget class>>descriptionExpand

^ MABooleanDescription new

default: self defaultExpand;

parameterName: 'expand';

accessor: #expand;

label: 'Expand';

priority: 310;

yourself

I would have expected an accessor "PRChildWidget>>expand:" to be called with the value: 'true'. I created my PRWidget derived class based on this assumption. However my equivalent setter was not being called and a closer look showed PRChildWidget to have no setters only getters. The getter reads as:

PRChildWidget>>expand

^ self read: #descriptionExpand

What's actually happening is "PRComponent>>description" is being called, not as I'd imagined: "PRChildWidget>>description".

tracing through the following code:

PRComponent>>write: anObject using: aDescription

(self basicDescription includes: aDescription)

ifTrue: [ super write: anObject using: aDescription ]

ifFalse: [

(anObject notNil and: [ aDescription isDocumentDescription ])

ifTrue: [ anObject owner: self ].

self settings at: aDescription put: anObject ]

reveals the code: "self settings at: aDescription put: anObject" is called, so "true" is placed in a settings Dictionary keyed by: #descriptionExpand

I've just about understood the code so far, and though I haven't traced through PRChildrenWidget instantiation it looks like in WAComponent>>initializeOwner:link: that the settings are copied to the newly created PRChildrenWidget object.

Phew.

I think I can see why there's complexity, but seems a shame that it in WAComponent>>initializeOwner:link: the code couldn't call the accessors of the componentClass assuming that the Magritte descriptions were configured to use an accessor pattern.

Or perhaps I've misunderstood??

Cheers

Nick