[Pharo-project] a little pearl from SystemProgressMorph

Stéphane Ducasse stephane.ducasse at inria.fr
Fri Jul 27 08:21:34 EDT 2012


On Jul 27, 2012, at 1:06 PM, Tudor Girba wrote:

> I checked in Pharo 2.0, and it looks ... well, how should I put it:
> it's confusing. You took a clear piece of code that could be printed
> on a nice A4 paper, and transformed it into a myriad of delegations.
> 
> I think you are just too afraid of if-statements. Clearly, a better
> solution would have been to just use caseOf:.

I did not check the code but using blocks as objects was a bad idea.

> 
> Doru
> 
> p.s. :)
> 
> 
> On Thu, Jul 26, 2012 at 8:55 PM, Stéphane Ducasse
> <stephane.ducasse at inria.fr> wrote:
>> And I removed the strip behavior.
>> In 2.0 it is not there.
>> 
>> Stef
>> 
>> On Jul 25, 2012, at 4:47 PM, Tudor Girba wrote:
>> 
>>> Just for fun read the below piece of code :)
>>> 
>>> 
>>> SystemProgressMorph>>label: shortDescription min: startMinValue max:
>>> startMaxValue
>>>      "Answer the block that updates the progress bar."
>>> 
>>>      "some fun stuff added (by kph)
>>> 
>>>      - bar value: #label. - tell me my current label.
>>>      - bar value: 'newLabel'. - enable changing the label from within the workBlock
>>>      - bar value: #increment. - enable progress by one without keeping a counter
>>>      - bar value: #decrement. - go backwards (if you really have to,
>>> useful for an abort, or rollback)!
>>> 
>>>      - bar value: newBigNum. - change the max on the fly - when you find
>>> there is more to do.
>>>      - bar value: (bar value: #setMax) + 20 - change the max on the fly -
>>> when you find there is more/less to do.
>>>      - bar value: (bar value: #setMin) - 20 - change the min on the fly -
>>> not sure why you would want to.
>>>      "
>>>      | slot range barSize lastRefresh maxValue minValue bar|
>>>      maxValue := startMaxValue.
>>>      minValue := startMinValue.
>>>      ((range := maxValue - minValue) <= 0 or: [(slot := self nextSlotFor:
>>> shortDescription) = 0])
>>>              ifTrue: [^[:barVal| 0 ]].
>>>      self recenter.
>>>      self openInWorld.
>>>      barSize := -1. "Enforces a inital draw of the morph"
>>>      lastRefresh := Time millisecondClockValue.
>>>      bar := bars at: slot.
>>>      ^[:barValArg | | barVal return newBarSize |
>>>              barVal := barValArg.
>>>              return := nil.
>>>              bar := bars at: slot.
>>>              "new fun stuff here"
>>>              barVal == #current  ifTrue: [ return := barSize ].
>>>              barVal == #label ifTrue:[ return := (labels at: slot) contents ].
>>>              barVal == #setMax ifTrue: [ return := maxValue. maxValue := minValue ].
>>>              barVal == #setMin ifTrue: [ return := minValue. minValue := maxValue ].
>>>              barVal == #increment ifTrue: [return := barVal := barSize + 1].
>>>              barVal == #decrement ifTrue: [ return := barVal := barSize - 1].
>>>              (barVal isString and: [barVal isSymbol not]) ifTrue: [
>>>                      (labels at: slot) contents: barVal.
>>>                      barVal := #refresh].
>>>              barVal == #refresh ifTrue: [self currentWorld displayWorld. return := true].
>>>              (barVal == SmallInteger maxVal or: [ barVal == #finished ]) ifTrue:
>>> [return := slot].
>>>              return ifNil: [
>>>                      barVal > maxValue ifTrue: [return := maxValue := barVal].
>>>                      barVal < minValue ifTrue: [return := minValue := barVal].
>>>                      (barVal between: minValue and: maxValue)
>>>                              ifTrue: [newBarSize := (barVal - minValue / range * BarWidth) truncated.
>>>                                              newBarSize = barSize
>>>                                                      ifFalse: [barSize := newBarSize.
>>>                                                                      (Time millisecondsSince: lastRefresh) > 25
>>>                                                                              ifTrue: [barVal := #refresh ]]].
>>>              barVal == #refresh ifTrue: [
>>>                                      ((bar valueOfProperty: #useStripes) ifNil: [false])
>>>                                              ifTrue: [bar fillStyle origin: bar position - ((Time
>>> millisecondClockValue // 50 \\ 30) @ 0)].
>>>                                      bar barSize: barSize.
>>>                                      self currentWorld displayWorld.
>>>                                      lastRefresh := Time millisecondClockValue]].
>>>              return]
>>> 
>>> Cheers,
>>> Doru
>>> 
>>> --
>>> www.tudorgirba.com
>>> 
>>> "Every thing has its own flow"
>>> 
>> 
>> 
> 
> 
> 
> -- 
> www.tudorgirba.com
> 
> "Every thing has its own flow"
> 





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