[Pharo-project] some patterns I would like to **kill**

Schwab,Wilhelm K bschwab at anest.ufl.edu
Sun Oct 24 10:36:06 EDT 2010


If I understand you, you took things normally stored in instance variables, and (redundantly?) stored them as properties, right?





________________________________________
From: pharo-project-bounces at lists.gforge.inria.fr [pharo-project-bounces at lists.gforge.inria.fr] On Behalf Of Igor Stasenko [siguctua at gmail.com]
Sent: Saturday, October 23, 2010 10:47 PM
To: Pharo-project at lists.gforge.inria.fr
Subject: Re: [Pharo-project] some patterns I would like to **kill**

On 23 October 2010 21:47, Schwab,Wilhelm K <bschwab at anest.ufl.edu> wrote:
> Hey, I want some credit here - for coming to Squeak's possible defense :)
>
> All I am saying is that there is a possible space/speed tradeoff with a twist.  There was a fair amount written about these decisions, which is why I know anything at all about them.  Adding an instance variable for a rarely used sub-morph of a widely-instantiated morph might be an opportunity to fail to learn from history.  Most likely, the patterns Stef has noticed are simply mis-uses of sparse storage.  The best way to proceed would be to find an example of it that has many instances in the image, profile, fix, and profile again to see if the fix hurts performance (or perhaps helps it).  The usual caveats about benchmarking being really hard to do well apply, of course.
>

I did some experiment(s) with Morphic, placing many morph aspects into
properties dictioary (such as color, border, borderwidth etc), and
these values are used in rendering all the time.
And i didn't noticed heavy speed degradation.

> Bill
>
>
> ________________________________________
> From: pharo-project-bounces at lists.gforge.inria.fr [pharo-project-bounces at lists.gforge.inria.fr] On Behalf Of Igor Stasenko [siguctua at gmail.com]
> Sent: Saturday, October 23, 2010 11:00 AM
> To: Pharo-project at lists.gforge.inria.fr
> Subject: Re: [Pharo-project] some patterns I would like to **kill**
>
> On 23 October 2010 17:13, Schwab,Wilhelm K <bschwab at anest.ufl.edu> wrote:
>> Stef,
>>
>> Of course.  But in terms of avoiding unintended consequences, just consider the points I raised.  Some of the avoidance of instance variables (extensions, etc.) might have been a good idea with the gc at the time but is now an ugly hack, or that sparse storage tricks were over-used.
>>
> Well, one way or another you have to tame the complexity somehow.
> Be it extra instvar, or putting it into extensions doesn't changes the
> model's concept: you need a reference to some object
> which is responsible for some specific stuff.
>
>
>> Bill
>>
>>
>>
>>
>> ________________________________________
>> From: pharo-project-bounces at lists.gforge.inria.fr [pharo-project-bounces at lists.gforge.inria.fr] On Behalf Of Stéphane Ducasse [stephane.ducasse at inria.fr]
>> Sent: Saturday, October 23, 2010 7:33 AM
>> To: Pharo-project at lists.gforge.inria.fr
>> Subject: Re: [Pharo-project] some patterns I would like to **kill**
>>
>> I think that if you have a container that contains morphs probably findA and other queries are useful.
>> Now for a button that is also at the same place a field is the best.
>>
>> Stef
>>
>>
>> On Oct 22, 2010, at 11:14 PM, Schwab,Wilhelm K wrote:
>>
>>> Stef,
>>>
>>> #respondsTo: - no argument.  More defensive programming (aka masked bugs).  Tests like this have their place, but are over-used in Squeak.
>>>
>>> Using #submorphs *might* be easier to defend.  Morphs were designed to be usable in large numbers, and one might argue (playing Devil's Advocate here) that lookups are cheaper than the additional gc load.  An instance variable could also cache stale information.  Of course, for something that is accessed frequently, an instance variable avoids the lookup and I agree that it is cleaner and easier to read.
>>>
>>> Bill
>>>
>>>
>>>
>>> ________________________________________
>>> From: pharo-project-bounces at lists.gforge.inria.fr [pharo-project-bounces at lists.gforge.inria.fr] On Behalf Of stephane ducasse [stephane.ducasse at free.fr]
>>> Sent: Thursday, October 21, 2010 4:47 PM
>>> To: Pharo Development
>>> Subject: [Pharo-project] some patterns I would like to **kill**
>>>
>>> Hi
>>>
>>> I was reading Pluggable and friends
>>> I identified some patterns.
>>>
>>>
>>> The respondsTo plague
>>> Examples:
>>>
>>> color := self fillStyle asColor.
>>>        (self labelMorph respondsTo: #enabled:)
>>>                ifTrue: [self labelMorph enabled: self enabled].
>>>        (self labelMorph respondsTo: #interactionState:)
>>>                ifTrue: [self labelMorph interactionState: self interactionState]
>>>
>>> (self labelMorph respondsTo: #enabled:) ifTrue: [
>>>        self labelMorph enabled: aBoolean].
>>>
>>> (self enabled not and: [self label isMorph and: [(self label respondsTo: #enabled:) not]])
>>>
>>>
>>> by construction a labelObject should be a morph and it should answer enabled: and the case where this is not the case should be fixed.
>>>
>>>
>>> Using submorphs to avoid one single inst var makes code quite ugly to read:
>>>
>>>
>>> labelMorph
>>>        "Answer the actual label morph."
>>>
>>>        self hasSubmorphs ifFalse: [^nil].
>>>        self firstSubmorph hasSubmorphs ifFalse: [^nil].
>>>        ^self firstSubmorph firstSubmorph
>>>
>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> Pharo-project mailing list
>>> Pharo-project at lists.gforge.inria.fr
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>>>
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>>
>>
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>
>
>
> --
> Best regards,
> Igor Stasenko AKA sig.
>
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--
Best regards,
Igor Stasenko AKA sig.

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