Using slot for Immutable check

[Ducasse]

I wonder if we could not use slots to handle such cases

opacity: aNumber

	self
		assert: [ aNumber between: 0.0 and: 1.0 ]
		description: [ 'Opacity value must be within interval [0..1]' ].

	opacity isNotNil
		ifTrue: [ (BlImmutableObjectChangeError object: self) signal ].

	self opacity = aNumber
		ifTrue: [ ^ self ].

	opacity := aNumber

[tinchodias]

I'd be better, I agree. We are converting the asserts of the style of aNumber between: 0.0 and: 1.0 to method comments.

[Ducasse]

The assert for range are useless. in Morphic I do not recall problem with such design in alpha or others.

[Ducasse]

Now the immutability is something else to me.