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Re: [Pharo-users] type checking in Smalltalk
by Dimitris Chloupis April 25, 2017

April 25, 2017

On Thu, Mar 30, 2017 at 5:04 PM Marc Hanisch via Pharo-users < pharo-users(a)lists.pharo.org> wrote: > Hello, > > I have a question which is more related to software engineering than to > Pharo, but I hope that someone can give me an useful hint ;-) > > > Thanks for any advice :-) > Marc > There are three schools of thought Static programming , Dynamic programming and Hybrid Programming *School of Static Programming * The school of Static Programming which has been originating from compiled languages (turn code from source code to machine code before execution) it follows a static approach to the code. This means everything is clearly predefined, planned ahead and follows strict rules. *Pros: * 1) because compilers have specific code that its intentions are clear its much easier for them to optimize performance, hence code tends to run much faster eg C code tends to be 100s to 1000s times faster than Python code 2) Certain bugs can be captured at compile time which makes code safer to deploy to client. The compiler usually can capture such bugs and display relevant warning and errors again because the compiler is more strict to what goes in and what gets out. *Cons:* 1) Changing code on the fly, while the code runs can be notorious hard to do because of these restrictions. This means it does not work well with coders that love to experiment and try new ideas on the fly. 2) Finding bugs also can be harder because of these restrictions, the coder cannot easily change code on the fly on execution and generally the programming language is much less forgiving not only when coding but also when trying to inspect code and debug it. 3) Overall design can be quite ugly in the shake of increased performance and safety and that may affect the design of code as well *School of Dynamic Programming* The school of Dynamic Programming originates from interpreted languages , though modern implementations have compilers that compile source code to byte code and an interpreter that converts byte code to machine code on execution. There is no need for planning ahead in dynamic coding, instead dynamic coding works on the basis of abstractions and its proud to be the father and mother of OOP. OOP is an abstraction based , dynamic coding workflow that dominates dynamic language and even modern statically compiled languages. *Pros:* 1) Code can change on the fly making coding much easier and beginner friendly 2) No need to plan ahead 3) more dynamic workflow also when debugging code that allows to interact and communicate with code real time *Cons:* 1) Performance is sacrificed, thats not obvious for code that executes at once but for code that repeats thousands to millions of times the slow downs depending on the implementation of the language can be anywhere between 10s of times to 1000s of times slower that a static language 2) Using the wrong data / object will not be easily reported beforehand and at times it can be hard to detect such problems. Other bugs can also be hard to be detected even under the use of helping tools that examine and evaluate code because of the generic nature of the code. *Hybrid Programming* Even though static languages give us static programming outside the box and dynamic languages give us dynamic programming outside the box, modern implementation allow for repetitively easily to mix these two workflows. Its also possible for the coder to implement his/her own features with a language. For example C language does not support OOP outside the box, but OOP implementations for C do exist most popular being GObjects used by the GTK+ library C++ and Java although statically typed languages support also more dynamic types through the use of templates and generics Dynamic languages also can come with a variety of tools that perform checks during runtime or even compile time. Also test driven development is very popular for performing this task allowing the coder to create code , launch with a single command thousands of tests and make sure his code passes even more strict guidelines than an average compiler for a statically compiled language. The catch however is that in both cases there are compromises, sub standard implementations and plain weird behavior. *Summary:* *There is no right and wrong, whether we talk about types or other features whether you will follow the dynamic school or the static school is up to you and you preferences.* Both approaches have pros and cons and both will make you waste time while coding. The future however looks more bright and promising for the dynamic school with the rise of AI. Compilers and developer tools in the future may be smarter not only detecting errors and common bugs but actually analyzing coder intentions and even coding philosophies. AI is already used for code analysis but its still on early stage but is none the less our very close future. Funny irony: The most popular scenario for future technology is quantum computing. Hardware by nature is "static" , you have to design it before hand and make sure it works almost perfectly before selling it. This is reflected to the basis of digital architecture where the smaller unit is bit which is always a number and always either 1 or 0. But with quantum computing the bit can inherit quantum properties and be both 1 and 0 at the same time. This will allow in the future for more flexible design of "dynamic" hardware allowing for hardware to also deal with abstractions directly.

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Gathering statistics on messages sent to an object
by Alistair Grant April 24, 2017

April 24, 2017

If you subscribe to pharo-dev you will have seen that I've been looking at the primitives used in DiskStore. As part of that investigation I wanted to get an idea of which messages are typically sent to DiskStore and how often. Denis Kudriashov provided a neat package that implements a "halt on next object call". I've been wanting to play with the package for a while and decided this was a good opportunity. I've extended that package to keep count of how many times messages are sent to a target object, e.g.: | point trace | point := 2@3. trace := ExternalSendStats logStatsFor: point. point x; y; angle; x. trace stats. "a Dictionary( #angle->1 #x->2 #y->1 )" The package is probably too simplistic, and there's bound to be other ways to do this, but it met my immediate needs and gave me a chance to try out the Ghost package. I'll extend it if and when I need to. Many thanks to Denis for making the Ghost package available, and hopefully this is useful for someone, or at least triggers some new ideas. Denis' original article is at: http://dionisiydk.blogspot.cz/2016/04/halt-next-object-call.html The extensions can be installed with: Metacello new baseline: 'AkgGhost'; repository: 'github://akgrant43/akg-ghost:master/mc'; load Cheers, Alistair

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[ANN] Pharo Spring Friday, April 28
by marcus.denker＠inrira.fr April 24, 2017

April 24, 2017

Hi, There will be again a Sprint this Friday. More infos here: https://association.pharo.org/event-2492488

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Pharodays early rate deadline
by Stephane Ducasse April 24, 2017

April 24, 2017

Hi the deadline to register to pharodays is approaching. After 29 of April you will pay more and we will not secure room for the diner. Please register Stef

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Octal multiplication
by nacho April 23, 2017

April 23, 2017

Hello, This could sound like a dumb question, it may be. If I print: 8r3 * 8r3 I get 9. It seems that Pharo converts first to decimal and then performs the multiplication. How do I get the result in octal which should be 8r11? Thanks! ----- Nacho Smalltalker apprentice. Buenos Aires, Argentina. -- View this message in context: http://forum.world.st/Octal-multiplication-tp4943364.html Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com.

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Re: [Pharo-users] PostgreSQL and Pharo 6
by Dimitris Chloupis April 23, 2017

April 23, 2017

thank you Benoit On Mon, Apr 17, 2017 at 4:23 AM Benoit St-Jean via Pharo-users < pharo-users(a)lists.pharo.org> wrote: > ODBC worked fine as well if you don't need native driver access > > ----------------- > BenoÃ®t St-Jean > Yahoo! Messenger: bstjean > Twitter: @BenLeChialeux > Pinterest: benoitstjean > Instagram: Chef_Benito > IRC: lamneth > Blogue: endormitoire.wordpress.com > "A standpoint is an intellectual horizon of radius zero". (A. Einstein) > > > ------------------------------ > *From:* Dimitris Chloupis <kilon.alios(a)gmail.com> > *To:* Any question about pharo is welcome <pharo-users(a)lists.pharo.org> > *Sent:* Sunday, April 16, 2017 4:37 AM > *Subject:* [Pharo-users] PostgreSQL and Pharo 6 > > Hey guys , I play with PostgreSQL and I really like it, sorry Esteban :D > > I am using Python for it but I would like to give access also to Pharo to > my database. I was informed that Garage has a driver for PostgreSQL , is > there any other candidate ? Any advice ? > > >

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[ANN] Prometheas : a Pharo wiki database
by Dimitris Chloupis April 21, 2017

April 21, 2017

Part of my Discord bot as a goal was to add the ability to create database entries so that people can quickly find documentation. It was quite a challenge for me because I had to learn how heroku works, PostgreSQL and all the other things but I did it!!! In any discord channel you have now 3 commands !doc , !docadd , !docremove 1) !doc <search_term> search for a term in the documentation database eg. !doc pharo 2) !docadd <search_term> <content> <tags> <links> add a new entry to the documentation database eg. !docadd "pharo" "Pharo is a modern implementation of Smalltalk" "{'smalltalk','live coding','language'}" "{'squeak','IDE'}" 3)!docremove <search_term> remove a term from database eg. !docremove pharo tags , is for more complex searches in the future, links for sending users to relevant documentation I am also planning to give access to pharo users to the database from inside the pharo image, if its easy enough to use PostgreSQL from inside Pharo. Currently the bot is fully coded in python. The goal is not to create a full documentation but rather quick help tips for fast pointing to the right direction. This is also an invite to experience pharo devs and newcomers to start adding to this database. The database is PostgreSQL , one of the most populars, I have nothing against MongoDB , its just that it works better with heroku where I host the database. But if in the future find a way to do it for free I can move to MongoDB, but no promises. Anyway this was an excuse for me to learn database programming that I had abandoned 25 years ago (DBASE). So have fun with this :)

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example in FFI manual not worked
by Yuriy Babah April 21, 2017

April 21, 2017

Hello everyone, I'm new to Pharo and have tried do example with structure in Unified FFI manual. FFIExternalStructure subclass: #MyStructure instanceVariableNames: '' classVariableNames: '' package: 'FFIDemo' MyStructure class>>#fieldsDesc ^ #( uint8 id; char * struct_name; uint name_length; ) MyStructure rebuildFieldAccessors . -> DoIt -> MessageNotUnderstood What's i do wrong? I do it in Pharo5 and 6, widows and os x. Sorry for my english, it's not my native language.

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example in FFI manual not worked
by Torsten Bergmann April 20, 2017

April 20, 2017

Hi Yuriy, I guess you subclassed your class from the (wrong) class "ExternalStructure" but in the guide it is "FFIExternalStructure". Make sure to accept in the browser: FFIExternalStructure subclass: #MyStructure instanceVariableNames: '' classVariableNames: '' package: 'FFIDemo' instead of ExternalStructure subclass: #MyStructure instanceVariableNames: '' classVariableNames: '' package: 'FFIDemo' to make the class MyStructure a subclass of FFIExternalStructure instead of ExternalStructure. Hope this helps! Bye Torsten

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VM/Image magic numbers (Re: Pharo 6 snap install)
by Ben Coman April 18, 2017

April 18, 2017

The "magic decode for image files" seems related and possibly *very* useful.... http://forum.world.st/magic-decode-for-image-files-td4941712.html#a4941837 Now traditionally the VM has been backward compatible with old Images, but Pharo doesn't necessarily adhere to that and policy IIUC is release specific VM/Image pairs. So does Pharo require extra magic numbers to co-ordinate this? And how would this interact with OpenSmalltalk policy on these magic numbers? cheers -ben On Sat, Apr 15, 2017 at 4:20 AM, Stephane Ducasse <stepharo.self(a)gmail.com> wrote: > > This is what we always have when we release and we freeze it. > The vm 60 will be compatible with latest pharo 60 image. > > > > On Fri, Apr 14, 2017 at 12:09 PM, Luke Gorrie <luke(a)snabb.co> wrote: >> >> On 14 April 2017 at 08:53, Stephane Ducasse <stepharo.self(a)gmail.com> wrote: >>> >>> We always try to have a major release around mid/end of april >> >> >> Once the dust settles, I think it would be wonderful to have this invariant: >> >> - The latest Pharo VM source release is compatible with the latest Pharo image. >> >> This would make it easy for me to help nix users. My job will be to package the latest source release of the VM, period, and I will know that users can use this to run the latest image. I don't have much scope to screw things up and make people sad e.g. by shipping a bad commit from the master branch. >> >> (Of course it makes life harder for you upstream Pharo maintainers. Now updating the VM source release is a blocker for releasing a new image. Could be that this is too constraining in practice, I dunno. I'm just a guy who wants to setup a stable Pharo that I can use to build an application :-)) >> >> >

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