May 2020 - Pharo-users - lists.pharo.org

FFI and absolute path to dll

by ASAM

Hello, I'm using Pharo 8 64bit on Windows 10 64bit. I am trying to access a 32bit dll via a relative path. I'm desperate. I've been reading the document (http://books.pharo.org/booklet-uffi/pdf/2020-02-12-uFFI-V1.0.1) all the time up and down but I can't find an example of absolute path and Windows. If e.g. my.dll file would be stored here. C:\Program Files (x86)\GALEP5\my.dll then what should the method win32ModuleName return? Another question came to me while reading the document. It is actually important to know whether the DLL was generated as cdecl or stdcall? The dll i try to call use stdcall. I would be very happy if someone helps me. I can no longer see the message "External module not found" :-) Thanks a lot! -- Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html

May 12, 2020

Re: [Pharo-users] Need help putting my Pharo package under source control

by tbrunz

This is the way to get the latest version of any of the booklets, their "work in progress" (WIP) versions. https://books.pharo.org/ lists most of the books on a splashy page that shows cover art, etc., but their versions can be behind the WIP versions. My experience has been that the WIP versions are preferable. (Note that not all booklets that are "in progress" have been submitted to the build process and resulted in a WIP document In these cases, you have the option of cloning the repository and examining each chapter file.) -t -- Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html

May 12, 2020

Re: [Pharo-users] Need help putting my Pharo package under source control

by tbrunz

Sorry about that... You should end up on a GitHub "Releases" page for each document. In the section for the top-most release, you should see an "> Assets (3)" control. Click the arrow to open it. It should then list a PDF, a ZIP, and a '.tar.gz' document. You probably want the PDF, which you can read on the screen and/or print out. Download the document to your system by clicking on its link. -t -- Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html

May 12, 2020

Re: [Pharo-users] [ANN] Pharo Compendium

by Sven Van Caekenberghe

Nice ;-) On 12 May 2020, at 16:35, Torsten Bergmann <astares(a)gmx.de> wrote: > > > Hi Sven, > > I added spotter search now. I prefixed the github spotter entries additionally with the user name (owner). > This way you will be able to quickly find tagged public projects by keying in the project and/or username. > > See attached picture for an example. > > Catalog loading is possible via spotter too. > > Have fun > T. > >> Gesendet: Mittwoch, 06. Mai 2020 um 14:24 Uhr >> Von: "Sven Van Caekenberghe" <sven(a)stfx.eu> >> An: "Any question about pharo is welcome" <pharo-users(a)lists.pharo.org> >> Betreff: Re: [Pharo-users] [ANN] Pharo Compendium >> >> Great work, Torsten, works like a charm ! >> >> Since all Github projects have a README.md maybe that could be used as well, it will certainly contain more information. >> >> Most projects have several keyswords as well, that could be useful to show. >> >> Also, why not add a 'clone & metacello install baseline of' command ? >> >> Another idea: allow spotter searching of the pharo compendium entries ? >> >> Sven >> >>> On 2 May 2020, at 22:34, Torsten Bergmann <astares(a)gmx.de> wrote: >>> >>> Hi, >>> >>> time flows and Pharo-Project is improving on all ends since its inception in 2008. As you know over time for the code project hosting we used >>> SqueakSource, SS3 repos and other and later switched to SmalltalkHub available on http://smalltalkhub.com. >>> Starting with Iceberg in Pharo 6 many community projects are now hosted elsewhere - most of them moved to GitHub. Pharo's git support allows >>> also for GitLab, BitBucket and other git hosting services. >>> >>> I still think easy and quick accessibility to external (re)sources directly from the image is key - especially for new users who often get lost >>> among all the various things that are available. Back in 2013 I therefore provided a small tool called ConfigBrowser as a replacement for >>> MetacelloConfigurationBrowser to easily load Metacello configs directly into Pharo. >>> >>> Later we improved quick loading with a primary tool called "Catalog" written by Esteban. Catalog is indexing every 24 hours all configs within >>> specific meta-repositories on SmalltalkHub (per Pharo version) like >>> >>> http://www.smalltalkhub.com/#!/~Pharo/MetaRepoForPharo80 >>> >>> to automatically build >>> >>> http://catalog.pharo.org/ >>> >>> and also a JSON source >>> >>> http://catalog.pharo.org/catalog/json >>> >>> The last one feeds the catalog browser and catalog spotter search within the Pharo image. >>> >>> So Catalog helped us and especially new Pharo users to find what is available as external project or package. Unfortunately some package maintainers >>> are too lazy and do not maintain their configs over old and new Pharo versions. Also SmalltalkHub.com is now seen as legacy and will only be available >>> in a read only mode or as a browseable archive soon. >>> >>> So we have to think about others steps beyond Catalog and (triggered by a recent discussion on Discord) I started now a simple tool that helped me >>> finding all GitHub projects marked with "pharo" as GitHub topic. I additionally also added previous catalog loading. More sources could be added >>> as well as some kind of custom stores/plugins. Maybe this tool could be the base for a future replacement of the catalog tool. >>> >>> Long story short - let me introduce "Pharo Compendium": >>> >>> Compendium is a new UI tool to list, browse and load Pharo artefacts from the web like: >>> >>> - GitHub Projects >>> - Catalog Projects >>> >>> and other >>> >>> By default there are two plugin packages available for GitHub and Catalog - but you can implement own ones easily to connect to other sources >>> on the web. Compendium is available on: >>> >>> https://github.com/astares/Pharo-Compendium >>> >>> It is implemented using the new Spec2 UI framework - so you need a recent Pharo 9 image to give it a try. Just run: >>> >>> Metacello new >>> repository: 'github://astares/Pharo-Compendium/src'; >>> baseline: 'Compendium'; >>> load >>> >>> to load the tool. Then go to "Tools" -> "Compendium Browser". Attached is a screenshot demoing the primary functionality. >>> >>> If you want your GitHub project to be listed in the tool you simply need to add the topic "pharo" to the GitHub repository on the GitHub webpage. >>> >>> Feel free to comment or help improving the tool by sending PR's. >>> >>> Thx >>> T. (aka astares) >>> >>> >>> <compendium.png> >> >> >> > <Compendium_Spotter.jpg>

May 12, 2020

Re: [Pharo-users] [ANN] Pharo Compendium

by Torsten Bergmann

Hi Sven, I added spotter search now. I prefixed the github spotter entries additionally with the user name (owner). This way you will be able to quickly find tagged public projects by keying in the project and/or username. See attached picture for an example. Catalog loading is possible via spotter too. Have fun T. > Gesendet: Mittwoch, 06. Mai 2020 um 14:24 Uhr > Von: "Sven Van Caekenberghe" <sven(a)stfx.eu> > An: "Any question about pharo is welcome" <pharo-users(a)lists.pharo.org> > Betreff: Re: [Pharo-users] [ANN] Pharo Compendium > > Great work, Torsten, works like a charm ! > > Since all Github projects have a README.md maybe that could be used as well, it will certainly contain more information. > > Most projects have several keyswords as well, that could be useful to show. > > Also, why not add a 'clone & metacello install baseline of' command ? > > Another idea: allow spotter searching of the pharo compendium entries ? > > Sven > > > On 2 May 2020, at 22:34, Torsten Bergmann <astares(a)gmx.de> wrote: > > > > Hi, > > > > time flows and Pharo-Project is improving on all ends since its inception in 2008. As you know over time for the code project hosting we used > > SqueakSource, SS3 repos and other and later switched to SmalltalkHub available on http://smalltalkhub.com. > > Starting with Iceberg in Pharo 6 many community projects are now hosted elsewhere - most of them moved to GitHub. Pharo's git support allows > > also for GitLab, BitBucket and other git hosting services. > > > > I still think easy and quick accessibility to external (re)sources directly from the image is key - especially for new users who often get lost > > among all the various things that are available. Back in 2013 I therefore provided a small tool called ConfigBrowser as a replacement for > > MetacelloConfigurationBrowser to easily load Metacello configs directly into Pharo. > > > > Later we improved quick loading with a primary tool called "Catalog" written by Esteban. Catalog is indexing every 24 hours all configs within > > specific meta-repositories on SmalltalkHub (per Pharo version) like > > > > http://www.smalltalkhub.com/#!/~Pharo/MetaRepoForPharo80 > > > > to automatically build > > > > http://catalog.pharo.org/ > > > > and also a JSON source > > > > http://catalog.pharo.org/catalog/json > > > > The last one feeds the catalog browser and catalog spotter search within the Pharo image. > > > > So Catalog helped us and especially new Pharo users to find what is available as external project or package. Unfortunately some package maintainers > > are too lazy and do not maintain their configs over old and new Pharo versions. Also SmalltalkHub.com is now seen as legacy and will only be available > > in a read only mode or as a browseable archive soon. > > > > So we have to think about others steps beyond Catalog and (triggered by a recent discussion on Discord) I started now a simple tool that helped me > > finding all GitHub projects marked with "pharo" as GitHub topic. I additionally also added previous catalog loading. More sources could be added > > as well as some kind of custom stores/plugins. Maybe this tool could be the base for a future replacement of the catalog tool. > > > > Long story short - let me introduce "Pharo Compendium": > > > > Compendium is a new UI tool to list, browse and load Pharo artefacts from the web like: > > > > - GitHub Projects > > - Catalog Projects > > > > and other > > > > By default there are two plugin packages available for GitHub and Catalog - but you can implement own ones easily to connect to other sources > > on the web. Compendium is available on: > > > > https://github.com/astares/Pharo-Compendium > > > > It is implemented using the new Spec2 UI framework - so you need a recent Pharo 9 image to give it a try. Just run: > > > > Metacello new > > repository: 'github://astares/Pharo-Compendium/src'; > > baseline: 'Compendium'; > > load > > > > to load the tool. Then go to "Tools" -> "Compendium Browser". Attached is a screenshot demoing the primary functionality. > > > > If you want your GitHub project to be listed in the tool you simply need to add the topic "pharo" to the GitHub repository on the GitHub webpage. > > > > Feel free to comment or help improving the tool by sending PR's. > > > > Thx > > T. (aka astares) > > > > > > <compendium.png> > > >

May 12, 2020

Re: Need help putting my Pharo package under source control

by MichaelKentBurns

Thank you for your answer. The links provided lead me to the project which is nice, but I was not able to find a fully rendered document. Can you point me at it? -- Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html

May 12, 2020

Re: [Pharo-users] Uptime

by CÃ©drick BÃ©ler

Clearly amazing ð Is it the setup you use ? https://ci.inria.fr/pharo-contribution/job/EnterprisePharoBook/lastSuccessf… Cheers, Cedrick PS: btw Sven, we (with a group of students did a naive and simple url shortener that would fit nicely to default zinc demos ;-) Here is the script for accessing registered urls (sweet): server := (ZnServer startDefaultOn: 9999) onRequestRespond: [ :request | | key | key := request requestLine uri segments last. dataBase at: key ifPresent: [:val | ZnResponse redirect: val ] ifAbsent: [ZnResponse badRequest: request]. ]. > Le 12 mai 2020 Ã 10:06, Sven Van Caekenberghe <sven(a)stfx.eu> a Ã©crit : > > ï»¿Hi, > > So here is a little anecdote from the real world. I was planning to update the OS on my Linux server, from Ubuntu 18.04 LTS to 20.04 LTS (Long Term Support). This small (Digital Ocean, 1GB RAM, 1 Core) cloud server runs 3 Pharo images with public facing web sites. > > The machine itself reports: > > $ uptime > 12:37:50 up 530 days, 21:46, 1 user, load average: 0.02, 0.04, 0.01 > > which means it hasn't been powered down or didn't restart in 530 days. > > I was surprised to discover that 2 of the Pharo images on that machine did just as well: > > $ ./repl.sh > Connecting to Telnet REPL at locahost:41011 > Trying 127.0.0.1... > Connected to localhost. > Escape character is '^]'. > Neo Console Pharo-7.0+alpha.build.660.sha.2eb9bd2f41e7b0bd8f9f4190906910f83c178ab1 (32 Bit) > pharo> get system.uptime > 405 days 20 hours 29 minutes > pharo> quit > Bye! > > $ ./repl.sh > Connecting to Telnet REPL at locahost:41001 > Trying 127.0.0.1... > Connected to localhost. > Escape character is '^]'. > Neo Console Pharo4.0 of 18 March 2013 update 40620 >> get system.uptime > 530 days 21 hours 44 minutes >> quit > Bye! > > So both Pharo 7 and Pharo 4 kept on doing their jobs for a very long time. I think this is a testament to the stability of Pharo and to what is possible. > > Regards, > > Sven > > -- > Sven Van Caekenberghe > Proudly supporting Pharo > http://pharo.org > http://association.pharo.org > http://consortium.pharo.org > >

May 12, 2020

Uptime

by Sven Van Caekenberghe

Hi, So here is a little anecdote from the real world. I was planning to update the OS on my Linux server, from Ubuntu 18.04 LTS to 20.04 LTS (Long Term Support). This small (Digital Ocean, 1GB RAM, 1 Core) cloud server runs 3 Pharo images with public facing web sites. The machine itself reports: $ uptime 12:37:50 up 530 days, 21:46, 1 user, load average: 0.02, 0.04, 0.01 which means it hasn't been powered down or didn't restart in 530 days. I was surprised to discover that 2 of the Pharo images on that machine did just as well: $ ./repl.sh Connecting to Telnet REPL at locahost:41011 Trying 127.0.0.1... Connected to localhost. Escape character is '^]'. Neo Console Pharo-7.0+alpha.build.660.sha.2eb9bd2f41e7b0bd8f9f4190906910f83c178ab1 (32 Bit) pharo> get system.uptime 405 days 20 hours 29 minutes pharo> quit Bye! $ ./repl.sh Connecting to Telnet REPL at locahost:41001 Trying 127.0.0.1... Connected to localhost. Escape character is '^]'. Neo Console Pharo4.0 of 18 March 2013 update 40620 > get system.uptime 530 days 21 hours 44 minutes > quit Bye! So both Pharo 7 and Pharo 4 kept on doing their jobs for a very long time. I think this is a testament to the stability of Pharo and to what is possible. Regards, Sven -- Sven Van Caekenberghe Proudly supporting Pharo http://pharo.org http://association.pharo.org http://consortium.pharo.org

May 12, 2020

Re: [Pharo-users] mentor question 4

by Richard Sargent

Richard, your diligence is awesome! I'm left feeling that, generally, objects should not implement nor understand #asString. I realize there is a lot of room for debate on this subject. On May 11, 2020 10:12:10 PM PDT, Richard O'Keefe <raoknz(a)gmail.com> wrote: >For what it's worth, here's a moderately thorough examination of >several >different Smalltalk systems. >Let A = astc, D = Dolphin, G = GNU Smalltalk, Q = Squeak, > S = ANSI standard, T = Strongtalk, V = VisualWorks, X = ST/X > >#asString > >ADGPQST!X Character => String with: self >ADGPQSTVX String => self >ADGPQSTVX Symbol => String withAll: self >......... Text/Paragraph, where provided, => underlying string. >A-G-----X Collection => String withAll: self >---PQ---- Collection => self printString >A........ ByteArray => "decoded as Unicode" >.DGPQ-TVX ByteArray => "decoded as Latin1" >ADG.Q..VX Filename => "unparse (Filename, FilePath, whatever) >AdgpQ.TVX URI => "unparse (ZnUrl in P) >Ad.PQ...X UUID => "unparse (d, GUID equivalent)" >.DGpq...X Number => self displayString "or self printString, maybe via >Object" >...PQ...X Object => self printString > >There's a rough consensus here: > - if something *is* textual (Character, String, Symbol, Text, > Paragraph) #asString returns it as a normal string > - if something is a parsed form of structured text (file name, > URI, UUID) its unparsed form is returned, converting it back > should yield an equal parsed form > - if something is a byte array, it may be converted to a string > (the rule is to preserve the bytes, my library presumes byte > arrays are UTF8-encoded) > - if numbers are accepted at all, their #printString is returned > - if is none of the above, but has a #name or #title, that is > commonly the result. > >The open question is what converting an array of characters using >#asString will do. There is at least one Smalltalk out there >where #(65 66 67) asString => 'ABC', but that's a step further >than I personally want, though it is consistent with ByteArray. > > > > >On Tue, 12 May 2020 at 11:16, Jerry Kott <jkott(a)image-ware.com> wrote: > >> Hi all, >> >> Iâve been lurking so far, but I must add my voice here and agree with >> Richard. >> >> The malleability of Smalltalk tempts people into implementing >#asString, >> #name, and similar semantically ambiguous method names. Like Richard, >I >> regretted every single time I (or someone else on my team before me) >> decided to use these. It goes back to âSmalltalk with Styleâ >(probably the >> best little red book you could ever own): write intention revealing >code >> whenever you can, and comment liberally when you canât. >> >> *Jerry Kott* >> This message has been digitally signed. >> PGP Fingerprint: >> A9181736DD2F1B6CC7CF9E51AC8514F48C0979A5 >> >> >> >> On 11-05-2020, at 2:48 PM, Richard Sargent <rsargent(a)5x5.on.ca> >wrote: >> >> >> >> On May 11, 2020 2:19:49 PM PDT, Richard O'Keefe <raoknz(a)gmail.com> >wrote: >> >> I was saying that I expected #($a $b $c) asString ==> 'abc'. >> >> >> Over the years, I found myself being opposed to the idea that all >objects >> can sensibly have an #asString implementation. When it's been done, >it >> ultimately caused more problems than it solved. >> >> Consider $(48 49 50) asString. Do you expect it to give you a string >with >> all the digits? Or perhaps it's meant to interpret the elements as >> byte-like things, as you would need for "String withAll: >aCollection". So, >> the numbers could be interpreted as codepoints, as they are in a >ByteArray. >> >> But, what does "(Array with: Object new with: ProcessScheduler) >asString" >> mean? >> >> It seems to me that having all objects understand #asString leads to >> confusion. >> >> If you want an array to print as its literal representation, >implement >> #printAsLiteral, so that your intention is clear. >> >> >> If you want something that can be read back, that's what #storeString >> is for, >> >> On Tue, 12 May 2020 at 01:28, StÃ©phane Ducasse >> <stephane.ducasse(a)inria.fr> wrote: >> >> >> >> >> On 5 May 2020, at 16:16, Richard O'Keefe <raoknz(a)gmail.com> wrote: >> >> By the way, while playing with this problem, I ran into a moderately >> painful issue. >> >> There is a reason that Smalltalk has both #printString (to get a >> printable representation of an object) and #asString (to convert a >> sequence to another kind of sequence with the same elements.) If I >> *want* #printString, I know where to find it. The definition in my >> Smalltalk no reads >> >> asString >> "What should #($a $b $c) do? >> - Blue Book, Inside Smalltalk, Apple Smalltalk-80: >> there is no #asString. >> - ANSI, VW, Dolphin, CSOM: >> #asString is defined on characters and strings >> (and things like file names and URIs that are sort of >> >> strings), >> >> so expect an error report. >> - VisualAge Smalltalk: >> '($a $b $c)' >> - Squeak and Pharo: >> '#($a $b $c)' >> - GNU Smalltalk, Smalltalk/X, and astc: >> 'abc' >> I don't intend any gratuitous incompatibility, but when there >> is no consensus to be compatible with, one must pick something, >> and this seems most useful. >> " >> ^String withAll: self >> >> Does anyone here know WHY Squeak and Pharo do what they do here? >> >> >> Oops I did not see the quotes on my screen.. >> >> #( a b c) asString >> >> '#(#a #b #c)â >> >> >> this is unclear to me why this is not good but I have no strong >> >> opinion >> >> that this is good. >> >> I worked on printString for literals because I wanted to have >> self evaluating properties for basic literal like in Scheme and >> >> others. >> >> where >> #t >> >> >> #t >> >> And I payed attention that we get the same for literal arrays. >> Now the conversion is open to me. >> >> #($a $b $c) asString >> >> >> '#($a $b $c)â >> >> In fact I do not really understand why a string >> >> #($a $b $c) asString would be '(a b c)â >> and its use >> if this is to nicely display in the ui I would have >> displayString doing it. >> >> S. >> >> >> >> On Wed, 6 May 2020 at 01:20, Richard O'Keefe <raoknz(a)gmail.com> >> >> wrote: >> >> >> >> The irony is that the code I was responding to ISN'T obviously >> >> correct. >> >> Indeed, I found it rather puzzling. >> The problem specification says that the input string may contain >> >> digits >> >> AND SPACES. The original message includes this: >> >> Strings of length 1 or less are not valid. Spaces are allowed in the >> input, but they should be stripped before checking. All other >> non-digit characters are disallowed. >> >> Now it isn't clear what "disallowed" means. I took it to mean "may >> >> occur and >> >> should simply mean the input is rejected as invalid." Perhaps "may >> >> not occur" >> >> was the intention. So we shall not quibble about such characters. >> >> But I can't for the life of me figure out how Trygve's code checks >> >> for spaces. >> >> One reason this is an issue is that the behaviour of #digitValue is >> >> not >> >> consistent between systems. >> Character space digitValue >> does not exist in the ANSI standard >> answers -1 in many Smalltalks (which is a pain) >> answers a positive integer that can't be mistake for a digit in my >> >> Smalltalk >> >> raises an exception in some Smalltalks. >> >> This is a comment I now have in my Smalltalk library for #digitValue >> "This is in the Blue Book, but unspecified on non-digits. >> Squeak, Pharo, Dolphin, VW, VAST, and Apple Smalltalk-80 >> answer -1 for characters that are not digits (or ASCII >> >> letters), >> >> which is unfortunate but consistent with Inside Smalltalk >> which specifies this result for non-digits. >> ST/X and GST raise an exception which is worse. >> Digitalk ST/V documentation doesn't specify the result. >> This selector is *much* easier to use safely if it >> returns a 'large' (>= 36) value for non-digits." >> >> Let's compare three versions, the two I compared last time, >> and the "version A" code I discussed before, which to my mind >> is fairly readable. >> >> "Don't add slowness": 1 (normalised time) >> "Trygve's code": 6.5 >> "High level code": 30.6 (or 4.7 times slower than Trygve's) >> >> Here's the "High level code". >> ^(aString allSatisfy: [:each | each isSpace or: [each isDigit]]) >> >> and: [ >> >> |digitsReverse| >> digitsReverse := (aString select: [:each | each isDigit]) >> >> reverse. >> >> digitsReverse size > 1 and: [ >> |evens odds evenSum oddSum| >> odds := digitsReverse withIndexSelect: [:y :i | i odd]. >> evens := digitsReverse withIndexSelect: [:x :i | i even]. >> oddSum := odds detectSum: [:y | y digitValue]. >> evenSum := evens detectSum: [:x | >> #(0 2 4 6 8 1 3 5 7 9) at: x digitValue + 1]. >> (oddSum + evenSum) \\ 10 = 0]] >> >> This is the kind of code I was recommending that Roelof write. >> >> As a rough guide, by counting traversals (including ones inside >> >> existing >> >> methods), I'd expect the "high level" code to be at least 10 times >> >> slower >> >> than the "no added slowness" code. >> >> We are in vehement agreement that there is a time to write high level >> really obvious easily testable and debuggable code, and that's most >> of the time, especially with programming exercises. >> >> I hope that we are also in agreement that factors of 30 (or even 6) >> *can* be a serious problem. I mean, if I wanted something that slow, >> I'd use Ruby. >> >> I hope we are also agreed that (with the exception of investigations >> like this one) the time to hack on something to make it faster is >> >> AFTER >> >> you have profiled it and determined that you have a problem. >> >> But I respectfully suggest that there is a difference taking slowness >> >> OUT >> >> and simply not going out of your way to add slowness in the first >> >> place. >> >> >> I'd also like to remark that my preference for methods that traverse >> >> a >> >> sequence exactly once has more to do with Smalltalk protocols than >> with efficiency. If the only method I perform on an object is #do: >> the method will work just as well for readable streams as for >> collections. If the only method I perform on an object is >> >> #reverseDo: >> >> the method will work just as well for Read[Write]Streams as for >> SequenceReadableCollections, at least in my library. It's just like >> trying to write #mean so that it works for Durations as well as >> >> Numbers. >> >> >> Oh heck, I suppose I should point out that much of the overheads in >> this case could be eliminated by a Self-style compiler doing dynamic >> inlining + loop fusion. There's no reason *in principle*, given >> >> enough >> >> people, money, and time, that the differences couldn't be greatly >> reduced in Pharo. >> >> On Tue, 5 May 2020 at 21:50, Trygve Reenskaug <trygver(a)ifi.uio.no> >> >> wrote: >> >> >> >> Richard, >> >> Thank you for looking at the code. It is comforting to learn that the >> >> code has been executed for a large number of examples without >breaking. >> The code is not primarily written for execution but for being read >and >> checked by the human end user. It would be nice if we could also >check >> that it gave the right answers, but I don't know how to do that. >> >> >> The first question is: Can a human domain expert read the code and >> >> sign their name for its correctness? >> >> >> >> When this is achieved, a programming expert will transcribe the first >> >> code to a professional quality program. This time, the second code >> should be reviewed by an independent programmer who signs their name >> for its correct transcription from the first version. >> >> >> --Trygve >> >> PS: In his 1991 Turing Award Lecture, Tony Hoare said: "There are two >> >> ways of constructing a software design: One way is to make it so >simple >> that there are obviously no deficiencies and the other is to make it >so >> complicated that there are no obvious deficiencies. The first method >is >> far more difficult." >> >> >> --Trygve >> >> On tirsdag.05.05.2020 04:41, Richard O'Keefe wrote: >> >> As a coding experiment, I adapted Trygve Reenskoug's code to my >> Smalltalk compiler, put in my code slightly tweaked, and benchmarked >> them on randomly generated data. >> >> Result: a factor of 6.3. >> >> In Squeak it was a factor of ten. >> >> I had not, in all honesty, expected it to to be so high. >> >> On Tue, 5 May 2020 at 02:00, Trygve Reenskaug <trygver(a)ifi.uio.no> >> >> wrote: >> >> >> A coding experiment. >> Consider a Scrum development environment. Every programming team has >> >> an end user as a member. >> >> The team's task is to code a credit card validity check. >> A first goal is that the user representative shall read the code and >> >> agree that it is a correct rendering of their code checker: >> >> >> luhnTest: trialNumber >> | s1 odd s2 even charValue reverse | >> ----------------------------------------------- >> " Luhn test according to Rosetta" >> "Reverse the order of the digits in the number." >> reverse := trialNumber reversed. >> "Take the first, third, ... and every other odd digit in the reversed >> >> digits and sum them to form the partial sum s1" >> >> s1 := 0. >> odd := true. >> reverse do: >> [:char | >> odd >> ifTrue: [ >> s1 := s1 + char digitValue. >> ]. >> odd := odd not >> ]. >> "Taking the second, fourth ... and every other even digit in the >> >> reversed digits: >> >> Multiply each digit by two and sum the digits if the answer is >> >> greater than nine to form partial sums for the even digits" >> >> "The subtracting 9 gives the same answer. " >> "Sum the partial sums of the even digits to form s2" >> s2 := 0. >> even := false. >> reverse do: >> [:char | >> even >> ifTrue: [ >> charValue := char digitValue * 2. >> charValue > 9 ifTrue: [charValue := charValue - >> >> 9]. >> >> s2 := s2 + charValue >> ]. >> even := even not >> ]. >> "If s1 + s2 ends in zero then the original number is in the form of a >> >> valid credit card number as verified by the Luhn test." >> >> ^(s1 + s2) asString last = $0 >> --------------------------------- >> Once this step is completed, the next step will be to make the code >> >> right without altering the algorithm (refactoring). The result should >> be readable and follow the team's conventions. >> >> >> >> P.S. code attached. >> >> >> -- >> >> The essence of object orientation is that objects collaborate to >> >> achieve a goal. >> >> Trygve Reenskaug mailto: trygver(a)ifi.uio.no >> Morgedalsvn. 5A http://folk.uio.no/trygver/ >> N-0378 Oslo http://fullOO.info >> Norway Tel: (+47) 468 58 625 >> >> >> >> -------------------------------------------- >> StÃ©phane Ducasse >> http://stephane.ducasse.free.fr / http://www.pharo.org >> 03 59 35 87 52 >> Assistant: Julie Jonas >> FAX 03 59 57 78 50 >> TEL 03 59 35 86 16 >> S. Ducasse - Inria >> 40, avenue Halley, >> Parc Scientifique de la Haute Borne, BÃ¢t.A, Park Plaza >> Villeneuve d'Ascq 59650 >> France >> >> >> >> >>

May 12, 2020

Re: [Pharo-users] mentor question 4

by Richard O'Keefe

For what it's worth, here's a moderately thorough examination of several different Smalltalk systems. Let A = astc, D = Dolphin, G = GNU Smalltalk, Q = Squeak, S = ANSI standard, T = Strongtalk, V = VisualWorks, X = ST/X #asString ADGPQST!X Character => String with: self ADGPQSTVX String => self ADGPQSTVX Symbol => String withAll: self ......... Text/Paragraph, where provided, => underlying string. A-G-----X Collection => String withAll: self ---PQ---- Collection => self printString A........ ByteArray => "decoded as Unicode" .DGPQ-TVX ByteArray => "decoded as Latin1" ADG.Q..VX Filename => "unparse (Filename, FilePath, whatever) AdgpQ.TVX URI => "unparse (ZnUrl in P) Ad.PQ...X UUID => "unparse (d, GUID equivalent)" .DGpq...X Number => self displayString "or self printString, maybe via Object" ...PQ...X Object => self printString There's a rough consensus here: - if something *is* textual (Character, String, Symbol, Text, Paragraph) #asString returns it as a normal string - if something is a parsed form of structured text (file name, URI, UUID) its unparsed form is returned, converting it back should yield an equal parsed form - if something is a byte array, it may be converted to a string (the rule is to preserve the bytes, my library presumes byte arrays are UTF8-encoded) - if numbers are accepted at all, their #printString is returned - if is none of the above, but has a #name or #title, that is commonly the result. The open question is what converting an array of characters using #asString will do. There is at least one Smalltalk out there where #(65 66 67) asString => 'ABC', but that's a step further than I personally want, though it is consistent with ByteArray. On Tue, 12 May 2020 at 11:16, Jerry Kott <jkott(a)image-ware.com> wrote: > Hi all, > > Iâve been lurking so far, but I must add my voice here and agree with > Richard. > > The malleability of Smalltalk tempts people into implementing #asString, > #name, and similar semantically ambiguous method names. Like Richard, I > regretted every single time I (or someone else on my team before me) > decided to use these. It goes back to âSmalltalk with Styleâ (probably the > best little red book you could ever own): write intention revealing code > whenever you can, and comment liberally when you canât. > > *Jerry Kott* > This message has been digitally signed. > PGP Fingerprint: > A9181736DD2F1B6CC7CF9E51AC8514F48C0979A5 > > > > On 11-05-2020, at 2:48 PM, Richard Sargent <rsargent(a)5x5.on.ca> wrote: > > > > On May 11, 2020 2:19:49 PM PDT, Richard O'Keefe <raoknz(a)gmail.com> wrote: > > I was saying that I expected #($a $b $c) asString ==> 'abc'. > > > Over the years, I found myself being opposed to the idea that all objects > can sensibly have an #asString implementation. When it's been done, it > ultimately caused more problems than it solved. > > Consider $(48 49 50) asString. Do you expect it to give you a string with > all the digits? Or perhaps it's meant to interpret the elements as > byte-like things, as you would need for "String withAll: aCollection". So, > the numbers could be interpreted as codepoints, as they are in a ByteArray. > > But, what does "(Array with: Object new with: ProcessScheduler) asString" > mean? > > It seems to me that having all objects understand #asString leads to > confusion. > > If you want an array to print as its literal representation, implement > #printAsLiteral, so that your intention is clear. > > > If you want something that can be read back, that's what #storeString > is for, > > On Tue, 12 May 2020 at 01:28, StÃ©phane Ducasse > <stephane.ducasse(a)inria.fr> wrote: > > > > > On 5 May 2020, at 16:16, Richard O'Keefe <raoknz(a)gmail.com> wrote: > > By the way, while playing with this problem, I ran into a moderately > painful issue. > > There is a reason that Smalltalk has both #printString (to get a > printable representation of an object) and #asString (to convert a > sequence to another kind of sequence with the same elements.) If I > *want* #printString, I know where to find it. The definition in my > Smalltalk no reads > > asString > "What should #($a $b $c) do? > - Blue Book, Inside Smalltalk, Apple Smalltalk-80: > there is no #asString. > - ANSI, VW, Dolphin, CSOM: > #asString is defined on characters and strings > (and things like file names and URIs that are sort of > > strings), > > so expect an error report. > - VisualAge Smalltalk: > '($a $b $c)' > - Squeak and Pharo: > '#($a $b $c)' > - GNU Smalltalk, Smalltalk/X, and astc: > 'abc' > I don't intend any gratuitous incompatibility, but when there > is no consensus to be compatible with, one must pick something, > and this seems most useful. > " > ^String withAll: self > > Does anyone here know WHY Squeak and Pharo do what they do here? > > > Oops I did not see the quotes on my screen.. > > #( a b c) asString > > '#(#a #b #c)â > > > this is unclear to me why this is not good but I have no strong > > opinion > > that this is good. > > I worked on printString for literals because I wanted to have > self evaluating properties for basic literal like in Scheme and > > others. > > where > #t > > > #t > > And I payed attention that we get the same for literal arrays. > Now the conversion is open to me. > > #($a $b $c) asString > > > '#($a $b $c)â > > In fact I do not really understand why a string > > #($a $b $c) asString would be '(a b c)â > and its use > if this is to nicely display in the ui I would have > displayString doing it. > > S. > > > > On Wed, 6 May 2020 at 01:20, Richard O'Keefe <raoknz(a)gmail.com> > > wrote: > > > > The irony is that the code I was responding to ISN'T obviously > > correct. > > Indeed, I found it rather puzzling. > The problem specification says that the input string may contain > > digits > > AND SPACES. The original message includes this: > > Strings of length 1 or less are not valid. Spaces are allowed in the > input, but they should be stripped before checking. All other > non-digit characters are disallowed. > > Now it isn't clear what "disallowed" means. I took it to mean "may > > occur and > > should simply mean the input is rejected as invalid." Perhaps "may > > not occur" > > was the intention. So we shall not quibble about such characters. > > But I can't for the life of me figure out how Trygve's code checks > > for spaces. > > One reason this is an issue is that the behaviour of #digitValue is > > not > > consistent between systems. > Character space digitValue > does not exist in the ANSI standard > answers -1 in many Smalltalks (which is a pain) > answers a positive integer that can't be mistake for a digit in my > > Smalltalk > > raises an exception in some Smalltalks. > > This is a comment I now have in my Smalltalk library for #digitValue > "This is in the Blue Book, but unspecified on non-digits. > Squeak, Pharo, Dolphin, VW, VAST, and Apple Smalltalk-80 > answer -1 for characters that are not digits (or ASCII > > letters), > > which is unfortunate but consistent with Inside Smalltalk > which specifies this result for non-digits. > ST/X and GST raise an exception which is worse. > Digitalk ST/V documentation doesn't specify the result. > This selector is *much* easier to use safely if it > returns a 'large' (>= 36) value for non-digits." > > Let's compare three versions, the two I compared last time, > and the "version A" code I discussed before, which to my mind > is fairly readable. > > "Don't add slowness": 1 (normalised time) > "Trygve's code": 6.5 > "High level code": 30.6 (or 4.7 times slower than Trygve's) > > Here's the "High level code". > ^(aString allSatisfy: [:each | each isSpace or: [each isDigit]]) > > and: [ > > |digitsReverse| > digitsReverse := (aString select: [:each | each isDigit]) > > reverse. > > digitsReverse size > 1 and: [ > |evens odds evenSum oddSum| > odds := digitsReverse withIndexSelect: [:y :i | i odd]. > evens := digitsReverse withIndexSelect: [:x :i | i even]. > oddSum := odds detectSum: [:y | y digitValue]. > evenSum := evens detectSum: [:x | > #(0 2 4 6 8 1 3 5 7 9) at: x digitValue + 1]. > (oddSum + evenSum) \\ 10 = 0]] > > This is the kind of code I was recommending that Roelof write. > > As a rough guide, by counting traversals (including ones inside > > existing > > methods), I'd expect the "high level" code to be at least 10 times > > slower > > than the "no added slowness" code. > > We are in vehement agreement that there is a time to write high level > really obvious easily testable and debuggable code, and that's most > of the time, especially with programming exercises. > > I hope that we are also in agreement that factors of 30 (or even 6) > *can* be a serious problem. I mean, if I wanted something that slow, > I'd use Ruby. > > I hope we are also agreed that (with the exception of investigations > like this one) the time to hack on something to make it faster is > > AFTER > > you have profiled it and determined that you have a problem. > > But I respectfully suggest that there is a difference taking slowness > > OUT > > and simply not going out of your way to add slowness in the first > > place. > > > I'd also like to remark that my preference for methods that traverse > > a > > sequence exactly once has more to do with Smalltalk protocols than > with efficiency. If the only method I perform on an object is #do: > the method will work just as well for readable streams as for > collections. If the only method I perform on an object is > > #reverseDo: > > the method will work just as well for Read[Write]Streams as for > SequenceReadableCollections, at least in my library. It's just like > trying to write #mean so that it works for Durations as well as > > Numbers. > > > Oh heck, I suppose I should point out that much of the overheads in > this case could be eliminated by a Self-style compiler doing dynamic > inlining + loop fusion. There's no reason *in principle*, given > > enough > > people, money, and time, that the differences couldn't be greatly > reduced in Pharo. > > On Tue, 5 May 2020 at 21:50, Trygve Reenskaug <trygver(a)ifi.uio.no> > > wrote: > > > > Richard, > > Thank you for looking at the code. It is comforting to learn that the > > code has been executed for a large number of examples without breaking. > The code is not primarily written for execution but for being read and > checked by the human end user. It would be nice if we could also check > that it gave the right answers, but I don't know how to do that. > > > The first question is: Can a human domain expert read the code and > > sign their name for its correctness? > > > > When this is achieved, a programming expert will transcribe the first > > code to a professional quality program. This time, the second code > should be reviewed by an independent programmer who signs their name > for its correct transcription from the first version. > > > --Trygve > > PS: In his 1991 Turing Award Lecture, Tony Hoare said: "There are two > > ways of constructing a software design: One way is to make it so simple > that there are obviously no deficiencies and the other is to make it so > complicated that there are no obvious deficiencies. The first method is > far more difficult." > > > --Trygve > > On tirsdag.05.05.2020 04:41, Richard O'Keefe wrote: > > As a coding experiment, I adapted Trygve Reenskoug's code to my > Smalltalk compiler, put in my code slightly tweaked, and benchmarked > them on randomly generated data. > > Result: a factor of 6.3. > > In Squeak it was a factor of ten. > > I had not, in all honesty, expected it to to be so high. > > On Tue, 5 May 2020 at 02:00, Trygve Reenskaug <trygver(a)ifi.uio.no> > > wrote: > > > A coding experiment. > Consider a Scrum development environment. Every programming team has > > an end user as a member. > > The team's task is to code a credit card validity check. > A first goal is that the user representative shall read the code and > > agree that it is a correct rendering of their code checker: > > > luhnTest: trialNumber > | s1 odd s2 even charValue reverse | > ----------------------------------------------- > " Luhn test according to Rosetta" > "Reverse the order of the digits in the number." > reverse := trialNumber reversed. > "Take the first, third, ... and every other odd digit in the reversed > > digits and sum them to form the partial sum s1" > > s1 := 0. > odd := true. > reverse do: > [:char | > odd > ifTrue: [ > s1 := s1 + char digitValue. > ]. > odd := odd not > ]. > "Taking the second, fourth ... and every other even digit in the > > reversed digits: > > Multiply each digit by two and sum the digits if the answer is > > greater than nine to form partial sums for the even digits" > > "The subtracting 9 gives the same answer. " > "Sum the partial sums of the even digits to form s2" > s2 := 0. > even := false. > reverse do: > [:char | > even > ifTrue: [ > charValue := char digitValue * 2. > charValue > 9 ifTrue: [charValue := charValue - > > 9]. > > s2 := s2 + charValue > ]. > even := even not > ]. > "If s1 + s2 ends in zero then the original number is in the form of a > > valid credit card number as verified by the Luhn test." > > ^(s1 + s2) asString last = $0 > --------------------------------- > Once this step is completed, the next step will be to make the code > > right without altering the algorithm (refactoring). The result should > be readable and follow the team's conventions. > > > > P.S. code attached. > > > -- > > The essence of object orientation is that objects collaborate to > > achieve a goal. > > Trygve Reenskaug mailto: trygver(a)ifi.uio.no > Morgedalsvn. 5A http://folk.uio.no/trygver/ > N-0378 Oslo http://fullOO.info > Norway Tel: (+47) 468 58 625 > > > > -------------------------------------------- > StÃ©phane Ducasse > http://stephane.ducasse.free.fr / http://www.pharo.org > 03 59 35 87 52 > Assistant: Julie Jonas > FAX 03 59 57 78 50 > TEL 03 59 35 86 16 > S. Ducasse - Inria > 40, avenue Halley, > Parc Scientifique de la Haute Borne, BÃ¢t.A, Park Plaza > Villeneuve d'Ascq 59650 > France > > > > >

May 12, 2020