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Re: Null Object Pattern

by Bernardo Ezequiel Contreras

if you are using the null object pattern then you should not write those checks (ifNil:ifNotNil:, isNil, isNotNil). you should send the message to an instance of the null object and that object should decide what to do. just an opinion. On Tue, Mar 15, 2022 at 3:16 PM <sean(a)clipperadams.com> wrote: > I had some chaining that was getting too complex due to many nil checks, > so I started to refactor using a Null Object. > > However, Iâm struggling a bit with the refactor due to inlining. Since > #ifNil: variants might be inlined, it seems that something like: > > anObject with a long chain of messages ifNotNil: [ :result | ââ¦â ] > > must be changed into something like: > > anObject with a long chain of messages isNil ifFalse: [ anObject with a > long chain of messages ââ¦â ]. > > Obviously, I can use a temp to have: > > result := anObject with a long chain of messages. > > result isNil ifFalse: [ result ââ¦â ]. > > But both seem ugly and make me question using this pattern. > > 1. > > What am I missing? > 2. > > After 40+ years of Mooreâs Law, can we turn off these inlines by > default? > > -- Bernardo E.C. Sent from a cheap desktop computer in South America.

March 16, 2022

Re: Null Object Pattern

by Richard O'Keefe

I have a bad feeling about this. To start with, why do you CARE whether a particular method is inlined or not? <quote> However, Iâm struggling a bit with the refactor due to inlining. Since #ifNil: variants might be inlined, it seems that something like: anObject with a long chain of messages ifNotNil: [ :result | ââ¦â ] must be changed into something like: anObject with a long chain of messages isNil ifFalse: [ anObject with a long chain of messages ââ¦â ]. </quote> This makes absolutely no sense to me. What makes you think that the combination "_ isNil ifFalse: [_]" will NOT be inlined? In Squeak, x ifNotNil: [...] turns into x; nil; ==; jumpFalse and x isNil ifFalse: [...] turns into x; send isNil; jumpFalse where "send isNil" is a single byte. I don't see a substantial difference here. (I'd have checked in Pharo, but after many interface changes I no longer know how to do view|bytecode.) The thing that rings loud alarm bells for me is there being "long chains" in the first place. Can you give an example? In my own programming, I've generally found that nils turning up in the middle of a chain indicates a serious design error somewhere. On Wed, 16 Mar 2022 at 07:16, <sean(a)clipperadams.com> wrote: > I had some chaining that was getting too complex due to many nil checks, > so I started to refactor using a Null Object. > > However, Iâm struggling a bit with the refactor due to inlining. Since > #ifNil: variants might be inlined, it seems that something like: > > anObject with a long chain of messages ifNotNil: [ :result | ââ¦â ] > > must be changed into something like: > > anObject with a long chain of messages isNil ifFalse: [ anObject with a > long chain of messages ââ¦â ]. > > Obviously, I can use a temp to have: > > result := anObject with a long chain of messages. > > result isNil ifFalse: [ result ââ¦â ]. > > But both seem ugly and make me question using this pattern. > > 1. > > What am I missing? > 2. > > After 40+ years of Mooreâs Law, can we turn off these inlines by > default? > >

March 16, 2022

Re: Null Object Pattern

by Esteban Maringolo

+1 Inlining breaks the fundamental piece of OOP: Message sends. I'm sure there are use cases where inlining adds a significant speedup, but for some messages, I prefer them to be sent. Regards! Esteban A. Maringolo On Tue, Mar 15, 2022 at 3:16 PM <sean(a)clipperadams.com> wrote: > > I had some chaining that was getting too complex due to many nil checks, so I started to refactor using a Null Object. > > However, Iâm struggling a bit with the refactor due to inlining. Since #ifNil: variants might be inlined, it seems that something like: > > anObject with a long chain of messages ifNotNil: [ :result | ââ¦â ] > > must be changed into something like: > > anObject with a long chain of messages isNil ifFalse: [ anObject with a long chain of messages ââ¦â ]. > > Obviously, I can use a temp to have: > > result := anObject with a long chain of messages. > > result isNil ifFalse: [ result ââ¦â ]. > > But both seem ugly and make me question using this pattern. > > What am I missing? > > After 40+ years of Mooreâs Law, can we turn off these inlines by default?

March 15, 2022

Null Object Pattern

by sean＠clipperadams.com

I had some chaining that was getting too complex due to many nil checks, so I started to refactor using a Null Object. However, Iâm struggling a bit with the refactor due to inlining. Since #ifNil: variants might be inlined, it seems that something like: anObject with a long chain of messages ifNotNil: \[ :result | ââ¦â \] must be changed into something like: anObject with a long chain of messages isNil ifFalse: \[ anObject with a long chain of messages ââ¦â \]. Obviously, I can use a temp to have: result := anObject with a long chain of messages. result isNil ifFalse: \[ result ââ¦â \]. But both seem ugly and make me question using this pattern. 1. What am I missing? 2. After 40+ years of Mooreâs Law, can we turn off these inlines by default?

March 15, 2022

Re: BlockClosure folding

by sean＠clipperadams.com

ComplexCondition as described in [Andres Valloud, "A Mentoring Course on Smalltalk"](http://www.lulu.com/product/paperback/a-mentoring-course-on-smalltalk/3788890) is available at http://www.squeaksource.com/ComplexCondition.html With it, you can do something like: ``` ^[a includes: $.], [b includes: $.] ifAllTrue: [a < b] ifAnyTrue: [b includes: $.] otherwise: [a > b] ```

March 15, 2022

Re: BlockClosure folding

by JuliÃ¡n Maestri

Not satisfying the equality, but you can use polymorphism. Block >> , aBlock ^ BlockCompositor andAll: OrderedCollection with: self with: aBlock BlockCompositor >> #, aBlock conditions add: aBlock. BlockCompositor >> value: anObject ^ conditions allSatisfy: [:e | e value: anObject ] I don't really like the name BlockCompositor, but can't think of a better name at the moment. You could also implement logic for #or: using #+ and: #anySatisfy: for example, but need to safeguard against mixing both conditions. On Mon, 14 Mar 2022 at 22:29, HernÃ¡n Morales Durand < hernan.morales(a)gmail.com> wrote: > I think I saw a coding pattern a while ago that allows you to do the > following: > > cond1 , cond2 , cond3 , cond4 > > And providing a kind of folding selector condition #and: you would get: > > [ cond1 and: [ cond2 and: [ cond3 and: [ cond4 ] ] ] ]. > > for example: > > conditions := [ : each | each firstName = 'Boca' ] , > [ : each | each lastName = 'Baret' ] , > [ : each | each fullName = 'Virgasia' ]. > > such that the following assert is met: > > self assert: conditions equals: [ : each | each firstName = 'Boca' and: [ > each lastName = 'Baret' and: [ each fullName = 'Virgasia' ] ] ]. > > Any ideas or pointers? > > Cheers, > > HernÃ¡n > >

March 15, 2022

BlockClosure folding

by HernÃ¡n Morales Durand

I think I saw a coding pattern a while ago that allows you to do the following: cond1 , cond2 , cond3 , cond4 And providing a kind of folding selector condition #and: you would get: [ cond1 and: [ cond2 and: [ cond3 and: [ cond4 ] ] ] ]. for example: conditions := [ : each | each firstName = 'Boca' ] , [ : each | each lastName = 'Baret' ] , [ : each | each fullName = 'Virgasia' ]. such that the following assert is met: self assert: conditions equals: [ : each | each firstName = 'Boca' and: [ each lastName = 'Baret' and: [ each fullName = 'Virgasia' ] ] ]. Any ideas or pointers? Cheers, HernÃ¡n

March 15, 2022

Re: pharo image and vm

by Esteban Lorenzano

but is true is not "recommended", I should phrase what is there better ;) Also VM should work anyway... but Ubuntu 16.04 is pretty old, I am no surprised it is not working properly (and no idea if we can make it work easily... I will let Pablo Tesone answer that)... in OBS we start by ubuntu 18.04 Esteban On Mar 14 2022, at 5:46 pm, Otto Behrens <otto(a)finworks.biz> wrote: > Thanks Esteban, > > I'm on Ubuntu 16.04. Where did I miss the "pointed in the download page"? If I go to https://pharo.org/download, I can see a section called > "Pharo standalone", with a link there to " > Pharo VM 9 for Linux: 64bit (default) (https://files.pharo.org/get-files/90/pharo64-linux-stable.zip) | 32bit (https://files.pharo.org/get-files/90/pharo-linux-stable.zip) > > > Why would that not work? > > I really prefer not to install a deb. More work for me now. > > > Otto Behrens > > > > +27 82 809 2375 > > > > > > > > > > > > > > > > > > > > > > > > www.finworks.biz (http://www.finworks.biz/) > > > > > > > > > > > Disclaimer & Confidentiality Note: This email is intended solely for the use of the individual or entity named above as it may contain information that is confidential and privileged. If you are not the intended recipient, be advised that any dissemination, distribution or copying of this email is strictly prohibited. FINWorks cannot be held liable by any person other than the addressee in respect of any opinions, conclusions, advice or other information contained in this email. > > > > > > > > > > > > > > On Mon, Mar 14, 2022 at 6:39 PM Esteban Lorenzano <estebanlm(a)netc.eu (mailto:estebanlm@netc.eu)> wrote: > > Hi, > > > > which is your distribution? > > In anycase, as pointed in the download page, preferred way in linux to install the vm is through openbuildservice: > > > > https://software.opensuse.org/download.html?project=devel:languages:pharo:l… > > can you try one of that and tell us if problem remains? > > > > Esteban > > On Mar 14 2022, at 5:28 pm, Otto Behrens <otto(a)finworks.biz (mailto:otto@finworks.biz)> wrote: > > > Hi, > > > > > > I downloaded a new pharo from > > > > > > https://files.pharo.org/get-files/90/pharo64.zip > > > https://files.pharo.org/get-files/90/pharo64-linux-stable.zip > > > > > > > > > When I start up the image with the VM, I get "Your VM is too old for this image. Please download the latest VM" > > > > > > None of the shortcut keys seem to work. Something like <ctrl>-c does nothing. Does this have something to do with the incorrect VM? > > > > > > What am I missing here? > > > > > > Thanks for your help > > > > > > > > > Otto Behrens > > > > > > > > > > > > +27 82 809 2375 > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > www.finworks.biz (http://www.finworks.biz/) > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Disclaimer & Confidentiality Note: This email is intended solely for the use of the individual or entity named above as it may contain information that is confidential and privileged. If you are not the intended recipient, be advised that any dissemination, distribution or copying of this email is strictly prohibited. FINWorks cannot be held liable by any person other than the addressee in respect of any opinions, conclusions, advice or other information contained in this email. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > >

March 14, 2022

Re: pharo image and vm

by Otto Behrens

Thanks Esteban, I'm on Ubuntu 16.04. Where did I miss the "pointed in the download page"? If I go to https://pharo.org/download, I can see a section called "Pharo standalone", with a link there to " - Pharo VM 9 for Linux: 64bit (default) <https://files.pharo.org/get-files/90/pharo64-linux-stable.zip> | 32bit <https://files.pharo.org/get-files/90/pharo-linux-stable.zip> Why would that not work? I really prefer not to install a deb. More work for me now. Otto Behrens +27 82 809 2375 [image: FINWorks] [image: FINWorks] <http://za.linkedin.com/in/waltherbehrens> www.finworks.biz Disclaimer & Confidentiality Note: This email is intended solely for the use of the individual or entity named above as it may contain information that is confidential and privileged. If you are not the intended recipient, be advised that any dissemination, distribution or copying of this email is strictly prohibited. FINWorks cannot be held liable by any person other than the addressee in respect of any opinions, conclusions, advice or other information contained in this email. On Mon, Mar 14, 2022 at 6:39 PM Esteban Lorenzano <estebanlm(a)netc.eu> wrote: > Hi, > > which is your distribution? > In anycase, as pointed in the download page, preferred way in linux to > install the vm is through openbuildservice: > > > https://software.opensuse.org/download.html?project=devel:languages:pharo:l… > can you try one of that and tell us if problem remains? > > Esteban > > On Mar 14 2022, at 5:28 pm, Otto Behrens <otto(a)finworks.biz> wrote: > > Hi, > > I downloaded a new pharo from > > https://files.pharo.org/get-files/90/pharo64.zip > https://files.pharo.org/get-files/90/pharo64-linux-stable.zip > > When I start up the image with the VM, I get "Your VM is too old for this > image. Please download the latest VM" > > None of the shortcut keys seem to work. Something like <ctrl>-c does > nothing. Does this have something to do with the incorrect VM? > > What am I missing here? > > Thanks for your help > > Otto Behrens > > +27 82 809 2375 > [image: FINWorks] > [image: FINWorks] <http://za.linkedin.com/in/waltherbehrens> > www.finworks.biz > > Disclaimer & Confidentiality Note: This email is intended solely for the > use of the individual or entity named above as it may contain information > that is confidential and privileged. If you are not the intended recipient, > be advised that any dissemination, distribution or copying of this email is > strictly prohibited. FINWorks cannot be held liable by any person other > than the addressee in respect of any opinions, conclusions, advice or other > information contained in this email. > >

March 14, 2022

Re: pharo image and vm

by Esteban Lorenzano

Hi, which is your distribution? In anycase, as pointed in the download page, preferred way in linux to install the vm is through openbuildservice: https://software.opensuse.org/download.html?project=devel:languages:pharo:l… can you try one of that and tell us if problem remains? Esteban On Mar 14 2022, at 5:28 pm, Otto Behrens <otto(a)finworks.biz> wrote: > Hi, > > I downloaded a new pharo from > > https://files.pharo.org/get-files/90/pharo64.zip > https://files.pharo.org/get-files/90/pharo64-linux-stable.zip > > > When I start up the image with the VM, I get "Your VM is too old for this image. Please download the latest VM" > > None of the shortcut keys seem to work. Something like <ctrl>-c does nothing. Does this have something to do with the incorrect VM? > > What am I missing here? > > Thanks for your help > > > Otto Behrens > > > > +27 82 809 2375 > > > > > > > > > > > > > > > > > > > > > > > > www.finworks.biz (http://www.finworks.biz/) > > > > > > > > > > > Disclaimer & Confidentiality Note: This email is intended solely for the use of the individual or entity named above as it may contain information that is confidential and privileged. If you are not the intended recipient, be advised that any dissemination, distribution or copying of this email is strictly prohibited. FINWorks cannot be held liable by any person other than the addressee in respect of any opinions, conclusions, advice or other information contained in this email. > > > > > > > > > > > > >

March 14, 2022