[Cuis] ColorEditor updated

[H. Hirzel]

On 11/3/15, KenD <Ken.Dickey at whidbey.com> wrote:
> On Mon, 02 Nov 2015 15:58:26 -0500
> "Dan Norton" <dnorton at mindspring.com> wrote:
>
>>.. I was casting about for some name besides " #when:send:to: mechanism"
>> for
>> use in a brief essay on PluggableListMorph Principles of Operation when I
>> came across
>> Signals. I already wrote a paragraph on Dependency Mechanism.
>
> I would talk about #when:send:to: as implementing the Observer Pattern.
>
>> So, the simple principle here is to just use #when:send:to: and forget
>> about or maybe
>> deprecate #changed: and #update:?
>
> Yes.  Let us work to eliminate #changed: !
>
>> However, I see a problem common to dependency and #when:send:to: which is
>> the
>> identification and explanation of the various symbols which are
>> communicated as the
>> parameters for send: or changed: . When you're trying to design a model or
>> view similar to
>> something already in existence, the tools are not much help with that.
>>
>> I'm thinking maybe: document in comments? <rant>Nah. We don't do
>> comments.</rant>
>
> We should certainly add clarifying comments!
>
> Your Comment Browser is a big help here.  Once people start using it more,
> comments will appear.
>
> I suggest sending Juan a code update with an added "Open Comment Browser"
> Help menu item which autoloads the same way as TerseGuide.
+1
>
> However, class comments are not usually where design patterns show up.  8^|
>
> In the case of #when:send:to: I suggest a slightly larger discussion around
> building paned windows which update dependent panes.
>
> What constitutes good style?  What code patterns help?
>
> Think "Useful Code Patterns" to augment "Useful Expressions".
+1
> You can do your own example, but looking at the ColorEditor:
>
> ColorEditor>>buildMorphicWindow
> 	"Create a useful ColorEditor window"
> 	
> 	self layoutMorph beRow; " A row of columns"
> 		 separation: 6;
> 		 addMorph: self buildColorPaneColumn;
> 		 addMorph: self buildSliderColumn;
> 		 addMorph: self buildRadioButtonColumn;
> 		 color: self backgroundColor.
> 		
> 	self model when: #colorChanged send: #refreshColor to: self.
> 	
> 	^ self
>
> So trying for good style (hey, I need to improve here too!) one uses:
>
> [Class]>buildMorphicWindow
>     [Add (construct each pane).. to layout]
>     [Add self or panes as observers]
>   ^ self
>
> Suggest
>   Smalltalk browseAllImplementorsOf: #buildMorphicWindow
> to see specific usage examples.
>
> Of course, we will suffer some embarrassment as our real code is less than
> ideal. 8^(
>
> But this is a great motivator to making our code better!  ;^)
>
>
> $0.02
> -KenD
>
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