[squeak-dev] The Trunk: Kernel-cbc.1163.mcz
Levente Uzonyi
leves at caesar.elte.hu
Mon Mar 26 23:05:52 UTC 2018
Hi Chris,
What if there's no real implementation in Boolean but
#subclassResponibility?
Levente
On Mon, 26 Mar 2018, Chris Cunningham wrote:
> Hi.
> On Sun, Mar 25, 2018 at 3:23 PM, Levente Uzonyi <leves at caesar.elte.hu> wrote:
> On Sun, 25 Mar 2018, Chris Cunningham wrote:
>
>
>
> On Mar 25, 2018 2:46 PM, "Levente Uzonyi" <leves at caesar.elte.hu> wrote:
> On Sun, 25 Mar 2018, commits at source.squeak.org wrote:
>
> Chris Cunningham uploaded a new version of Kernel to project The Trunk:
> http://source.squeak.org/trunk/Kernel-cbc.1163.mcz
>
> ==================== Summary ====================
>
> Name: Kernel-cbc.1163
> Author: cbc
> Time: 21 March 2018, 9:09:20.773568 pm
> UUID: 45d9dad8-7c81-034e-b578-b9ccd291cab6
> Ancestors: Kernel-dtl.1162, Kernel-fn.1152
>
> Update #xor: to work with argument being a block as well.
>
> =============== Diff against Kernel-dtl.1162 ===============
>
> Item was added:
> + ----- Method: Boolean>>xor: (in category 'logical operations') -----
> + xor: aBoolean + "Exclusive OR. Answer true if the receiver is not equivalent to aBoolean."
> + + ^(self == aBoolean) not!
>
>
> Why not just
>
> ^self ~~ aBoolean
>
> Because that lets you xor between Boolean and other a
> Odd stuff. Meaning bugs can creep in without any errors being raised.
>
>
> Am I missing something? Is there a case when [a~~b] and [(a==b)not] yield different results where a and b can be any object?
>
> You are not missing anything - I misunderstood your question the first time around (which is why my response was garbage - at least, this time why).
>
> Yes, that could be fixed, and would provide a clue as to an alternative fast version.
>
> However, I wonder what a right fix would be? The subclasses now make sure the arguments equate to a boolean - and it would be weird to have the super class not care about that. On the other hand, having the
> super class use ~~ would give the pointer of how to make it really fast - and a more generic explanation. Hmm.
>
> Maybe I could switch it around, and add a few comments about how this isn't 'safe' but is fast, and also take the opportunity to make better variable names in the subclasses.
>
> -cbc
> Also, this method is overridden in all subclasses, isn't it?
>
> Yes ~~ is faster - but xor: is already fast.
>
>
> It's not about speed. It's about unnecessary complexity.
>
> Levente
>
>
> ?
>
>
> Item was changed:
> ----- Method: False>>xor: (in category 'logical operations') -----
> xor: aBoolean
> + "aBoolean is either a boolean, or an object who's #value returns a boolean (usually a block)."
> + ^aBoolean value ifTrue: [ true ] ifFalse: [ false ]!
>
>
> I think the parameter should have a better name, because the #value send doesn't make much sense when you read the code.
>
> I guess so.
>
> Levente
>
> - "Posted by Eliot Miranda to squeak-dev on 3/24/2009"
> - - ^aBoolean!
>
> Item was changed:
> ----- Method: True>>xor: (in category 'logical operations') -----
> xor: aBoolean
> + "aBoolean is either a boolean, or an object who's #value returns a boolean (usually a block)."
> + ^aBoolean value ifTrue: [ false ] ifFalse: [ true ]!
> - "Posted by Eliot Miranda to squeak-dev on 3/24/2009"
> - - ^aBoolean not!
>
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