September 2017 - Pharo-users

Re: [Pharo-users] How to find if a method is being executed in a given process

by Stephane Ducasse

This is exactly my usecase, i need to remove code that may be called by a method on the stack - and i know exactly which method. However my base hypothesis is that it is in an already running process (maybe a loop) and that part i cannot change. Is there an existing Pharo implementation of MethodWrappers ? How can you remove a method if it may be called? Stef On Mon, Sep 25, 2017 at 4:16 PM, Marcus Denker <marcus.denker(a)inria.fr> wrote: > > On 25 Sep 2017, at 15:19, Steven Costiou <steven.costiou(a)kloum.io> wrote: > > > > Le 2017-09-25 12:21, jtuchel(a)objektfabrik.de wrote : > > Steven > > You could add use a semaphore if changing code is an option. > We once used MethodWrappers in VAST to answer a similar question regarding > whether a body of code can be removed from a system. > > Joachim > > > > This is exactly my usecase, i need to remove code that may be called by a > method on the stack - and i know exactly which method. However my base > hypothesis is that it is in an already running process (maybe a loop) and > that part i cannot change. Is there an existing Pharo implementation of > MethodWrappers ? > > > > I do not know how MethodWrappers would solve this.. in the end, they do > something very similar to what happens when you put a MetaLink on a > methodNodeâ¦ > (we do not wrap but recompile the AST instead, wrapping is used if the > method has a primitive, though). > > You can even see MetaLinks as âjustâ a generalisation of methodWrappers to > any AST node. > > So you would have the same problem: the wrapper is used *for the next call*. > > Marcus

Sept. 25, 2017

Re: [Pharo-users] NeoJSON and polymorphism

by Juraj Kubelka

Hi Sven, thank you! In the NeoJSON repository, you likely want to merge Neo-JSON-Core-SvenVanCaekenberghe.43 and 44. And the same for the test cases. > On Sep 24, 2017, at 06:05, Sven Van Caekenberghe <sven(a)stfx.eu> wrote: > > Hi Juraj, > > This would be a simpler form of the type/class tags that are often used in JSON encoding. Since there are many ways to do this, there cannot be one solution. NeoJSON mapping was not designed to cover these cases. Nor is JSON meant to do this. STON is one (rather elegant if I may say so) answer to this problem. Your example would be encoded as > > [ > PngAttachement { #url:'http://example.com/random-name.txt', #fileName:'chapter-one.txt' }, > TxtAttachement { #url:'http://example.com/random-name.png', #fileName:'image.png' } > ] About STON usage, I wonder how it works in terms of a data structure evolution. Currently I use JSON format to store a data permanently. The data are supposed to be accesible for a long time (years). I am pretty sure that the protocol will evolve and we will end up with several JSON versions. I think that having different JSON mapping schemes will allow to map old JSON versions to a latest object structure (or to several different versions if necessary). For the example above, think of the scenario that PngAttachment does not exist anymore. In a simple scenario there could be an ImageAttachment class instead with the same instance variables. In a more complex scenario, there could be a AttachmentTwo { #type: AttachmentTwoType { â¦ instances â¦ }, #path: AttachmentTwoPath { â¦ instances â¦ } }. I can use JSON mappings that transform the old JSON version to the new class structure. I am not sure if STON is that flexible. What do you think? Do I miss something? > > Still, the question of how to do this kind of dynamic decoding is an interesting challenge. Please update to the following commits: > > === > Name: Neo-JSON-Core-SvenVanCaekenberghe.44 > Author: SvenVanCaekenberghe > Time: 22 September 2017, 3:24:51.679449 pm > UUID: f1ebeade-2816-0d00-a04c-ae370e598362 > Ancestors: Neo-JSON-Core-SvenVanCaekenberghe.42 > > Implement some missing code in NeoJSONCustomMapping (the writing part of #listOfElementSchema: #listOfType:andElementSchema: #mapWithValueSchema:) > > Add NeoJSONStreamingWriter>>#writeElementAs: > > Add NeoJSONMappingTests>>#testDynamicTyping as an example > === > Name: Neo-JSON-Tests-SvenVanCaekenberghe.41 > Author: SvenVanCaekenberghe > Time: 22 September 2017, 3:25:09.881494 pm > UUID: a9a900e0-2816-0d00-a04d-a6fb0e598362 > Ancestors: Neo-JSON-Tests-SvenVanCaekenberghe.39 > > Implement some missing code in NeoJSONCustomMapping (the writing part of #listOfElementSchema: #listOfType:andElementSchema: #mapWithValueSchema:) > > Add NeoJSONStreamingWriter>>#writeElementAs: > > Add NeoJSONMappingTests>>#testDynamicTyping as an example > === > > Now you can do as follows: > > NeoJSONMappingTests>>#testDynamicTyping > | data customMapping json result | > data := Array with: #foo->1 with: #(foo 2). > "The idea is to map a key value combination as either a classic association or a simple pair, > using key & value properties as well as a type property to distinguish between the two" > customMapping := [ :mapper | > mapper > for: #AssocOrPair customDo: [ :mapping | > mapping > encoder: [ :x | > x isArray > ifTrue: [ { #type->#pair. #key->x first. #value->x second } asDictionary ] > ifFalse: [ { #type->#assoc. #key->x key. #value->x value } asDictionary ] ]; > decoder: [ :x | > (x at: #type) = #pair > ifTrue: [ Array with: (x at: #key) with: (x at: #value) ] > ifFalse: [ (x at: #key) -> (x at: #value)] ] ]; > for: #ArrayOfAssocOrPair customDo: [ :mapping | > mapping listOfType: Array andElementSchema: #AssocOrPair ]; > yourself ]. > json := String streamContents: [ :out | > (customMapping value: (NeoJSONWriter on: out)) nextPut: data as: #ArrayOfAssocOrPair ]. > result := (customMapping value: (NeoJSONReader on: json readStream)) nextAs: #ArrayOfAssocOrPair. > self assert: result equals: data > > Everything is virtual (not implemented as methods on actual classes) which makes the example self contained and non intrusive, but not very elegant, nor object oriented or extendable. Also, it is not as efficient as NeoJSON mapping was designed for, since it creates intermediate structures. Nice example. If #decoder: and #encoder: are used, is it still possible to use inner mappings? For example in my previous example, one instance variable is a ZnUrl instance that is stored as a String. Can I say âuse ZnUrl mapping in for this intermediate structureâ? Well, I understand that I can hard code it directly in the the #decoder: and #encoder: messages using #asZnUrl and #asString messages. I am thinking about a more complicated structures that involves more mapping definitions. Thanks! Juraj > > HTH, > > Sven > >> On 21 Sep 2017, at 22:07, Juraj Kubelka <juraj.kubelka(a)icloud.com> wrote: >> >> Hi, >> >> By studying the NeoJSON book chapter (Pharo Enterprise), I do not understand how to modify the following example: >> >> -=-=-=-=-=-=-=- >> "Let us say that we have an Attachment class..." >> >> Object subclass: #Attachment >> instanceVariableNames: 'url fileName' >> classVariableNames: '' >> package: 'NeoJSON-Use-Case'. >> >> "...with url: and fileName: methods." >> Attachment compile: 'url: anObject', String cr, String tab, 'url := anObject' classified: 'accessing'. >> Attachment compile: 'fileName: anObject', String cr, String tab, 'fileName := anObject' classified: 'accessing'. >> >> "Let's create a collection of two instances:" >> collectionOne := { >> Attachment new >> url: 'http://example.com/random-name.txt' asZnUrl; >> fileName: 'chapter-one.txt' >> yourself. >> Attachment new >> url: 'http://example.com/random-name.png' asZnUrl; >> fileName: 'image.png'; >> yourself. >> }. >> >> "And let's map it to a JSON structure:" >> String streamContents: [ :aStream | >> (NeoJSONWriter on: aStream) >> for: #CollectionOfAttachments customDo: [ :mapping | >> mapping listOfElementSchema: Attachment ]; >> mapAllInstVarsFor: Attachment; >> for: ZnUrl customDo: [ :mapping | >> mapping encoder: [ :aZnUrl | >> aZnUrl asString ] ]; >> nextPut: collectionOne as: #CollectionOfAttachments. >> ]. >> >> "And read the JSON structure:" >> (NeoJSONReader on: '[{"url":"http://example.com/random-name.txt","fileName":"chapter-one.txt"},{"url":"http://example.com/random-name.png","fileName":"image.png"}]' readStream) >> for: #CollectionOfAttachments customDo: [ :mapping | >> mapping listOfElementSchema: Attachment ]; >> for: Attachment do: [ :mapping | >> mapping mapInstVar: 'fileName'. >> (mapping mapInstVar: 'url') valueSchema: ZnUrl ]; >> for: ZnUrl customDo: [ :mapping | >> mapping decoder: [ :string | >> string asZnUrl ] ]; >> nextAs: #CollectionOfAttachments. >> >> "=======================" >> âThe previous example works perfectly, including the ZnUrl mapping (notice that url variables have ZnUrl instances). >> >> Now, let's say that we want to distinguish PNG and TXT attachments. >> For that reason we will create two Attachment subclasses..." >> >> Attachment subclass: #PngAttachment >> instanceVariableNames: '' >> classVariableNames: '' >> package: 'NeoJSON-Use-Case'. >> >> Attachment subclass: #TxtAttachment >> instanceVariableNames: '' >> classVariableNames: '' >> package: 'NeoJSON-Use-Case'. >> >> "...with type methods that might be used in a new JSON structure:" >> PngAttachment compile: 'type', String cr, String tab, '^ ''png''' classified: 'accessing'. >> TxtAttachment compile: 'type', String cr, String tab, '^ ''txt''' classified: 'accessing'. >> >> "Let's create a collection with the PNG and TXT instances:" >> collectionTwo := { >> TxtAttachment new >> url: 'http://example.com/random-name.txt' asZnUrl; >> fileName: 'chapter-one.txt' >> yourself. >> PngAttachment new >> url: 'http://example.com/random-name.png' asZnUrl; >> fileName: 'image.png'; >> yourself. >> }. >> >> "How can I modify NeoJSONWriter and NeoJSONReader mappings? >> >> The JSON structure should (ideally) looks like this:" >> >> '[ >> {âtypeâ:âtxtâ,"url":"http://example.com/random-name.txt","fileName":"chapter-one.txtâ}, >> {âtypeâ:âpngâ,"url":"http://example.com/random-name.png","fileName":"image.pngâ} >> ]' >> -=-=-=-=-=-=-=- >> >> I would like to keep the mapping isolated (without defining neoJsonOn: methods). >> >> Thank you! >> Juraj >> > >

Sept. 25, 2017

Re: [Pharo-users] How to find if a method is being executed in a given process

by Marcus Denker

> On 25 Sep 2017, at 15:19, Steven Costiou <steven.costiou(a)kloum.io> wrote: > > > Le 2017-09-25 12:21, jtuchel(a)objektfabrik.de wrote : > >> Steven >> >> You could add use a semaphore if changing code is an option. >> We once used MethodWrappers in VAST to answer a similar question regarding whether a body of code can be removed from a system. >> >> Joachim > > This is exactly my usecase, i need to remove code that may be called by a method on the stack - and i know exactly which method. However my base hypothesis is that it is in an already running process (maybe a loop) and that part i cannot change. Is there an existing Pharo implementation of MethodWrappers ? > > I do not know how MethodWrappers would solve this.. in the end, they do something very similar to what happens when you put a MetaLink on a methodNodeâ¦ (we do not wrap but recompile the AST instead, wrapping is used if the method has a primitive, though). You can even see MetaLinks as âjustâ a generalisation of methodWrappers to any AST node. So you would have the same problem: the wrapper is used *for the next call*. Marcus

Sept. 25, 2017

Re: [Pharo-users] How to find if a method is being executed in a given process

by Ben Coman

On Mon, Sep 25, 2017 at 9:19 PM, Steven Costiou <steven.costiou(a)kloum.io> wrote: > > > Le 2017-09-25 12:21, jtuchel(a)objektfabrik.de wrote : > > Steven > > You could add use a semaphore if changing code is an option. > We once used MethodWrappers in VAST to answer a similar question regarding > whether a body of code can be removed from a system. > > Joachim > > > > This is exactly my usecase, i need to remove code that may be called by a > method on the stack - and i know exactly which method. However my base > hypothesis is that it is in an already running process (maybe a loop) and > that part i cannot change. Is there an existing Pharo implementation of > MethodWrappers ? > > > > Le 2017-09-25 14:32, Ben Coman wrote : > > > I'm not sure if your wanting something more built in, or just "some way", > so for the latter, consider wrapping in with your own status flags... > > status := #setup. > watcher := [[true] whileTrue:[ > Transcript crShow: status. > 900 milliSeconds wait] > ] forkAt:36. > result := 0. > worker := [[true] whileTrue:[ > status := #WORKING. > 1 second wait. > result := result + 1. > Transcript crShow: result. > status:=#waiting. > 3 seconds wait] > ] forkAt:35. > worker suspend. > worker resume. > > cheers -ben > > > I want to avoid adding control in the code, because hypothetically the > process i want to check is already running and possibly written by somebody > else. I've think about a similar solution using metalinks, but if the loop > is on the stack then i don't know what i can do. > > > > Le 2017-09-25 12:42, Marcus Denker a wrote : > > you could iterate all processes, there then get the stack and look up the > sender chain > if the method is somewhere to be found. If yes -> it is exectuted right > now. > > One problem is that which methods are on the stack changes, so you should > try to avoid process switches while doing the analysis. > > Marcus > > Ok so if i know which process to analyse, i can just do something like the > following that i found in the Halt class: > > [ cntxt isNil ] whileFalse: [ > cntxt selector = aSelector ifTrue: [ ... ]. > cntxt := cntxt sender ] > > But if i actually found the method i was looking for on the stack, can i > somehow ask the suspended context to "execute" until it returns from this > method ? > > Steven. > > > See Halt class >> now has pragma <debuggerCompleteToSender>. Look at its senders and maybe Process>>compelte: give you some dieas. cheers -ben

Sept. 25, 2017

Re: [Pharo-users] Pharo 7 license question

by Jimmie Houchin

Hello, thanks for the reply. I have thought about recursive and unfortunately it is not in my opinion an adequate or equivalent substitute. It may be inoffensive, but it is not accurate in conveying those properties or characteristics of the GPL. Something that is recursive generally makes repeated calls to itself. It is neatly contained and does not propagate outside of itself. Calling a recursive method does not make the call chain all the way up to main recursive. The recursive method does its recursion and generally returns its result back to the caller, ending the recursion. The only thing the caller receives is the results, not the recursion. There are many positive cultural references to something viral or infect(ious). For something to go viral, depends on what that something is. She has an infectious smile, or laugh. Even in biology where we get the term viral. It is not absolutely or always negative. There are things that scientist attempt to use viral characteristics to do good things. Context is everything. There are no words a GPL proponent could provide which adequately or otherwise describe the viral characteristic of the GPL that would be considered positive by a GPL opponent. Back to context. To a GPL proponent, the viral nature of the GPL is considered a positive and good thing. It is the primary reason to choose and use the GPL. To the GPL opponent, the viral nature of the GPL is considered a negative and bad thing. It is the primary reason to oppose and to avoid using the GPL. Two side both viewing the same exact thing and understanding it very differently. One positive, one negative. There is no positive spin for this aspect of the GPL for someone wishing to avoid that aspect. No matter what words are chosen. For the MIT/BSD person we don't necessarily care if you wish to license your software under the GPL. What we care is that your software is expressly and explicitly trying to override our choices and compel us to become GPL. That is what we don't like. The fact that GPL software is GPL software in perpetuity is okay. Just leave us alone. But we know that is not how the GPL works. A perspective occurred to me this morning. The original author of GPL software is not bound by the GPL. They have freedoms the GPL takes away. They have the freedom to turn their software into closed source, proprietary software. They have the freedom to not release all of their modifications. They have the freedom to not infect all their other software which may use this otherwise GPLd code. They have freedom to relicense their software. They have many, many freedoms which the GPL removes from everyone who receives the GPLd software. The original author of GPL software has for himself MIT like freedoms. What we on the MIT/BSD side of things want is for everybody to have all of the freedoms the original author of the software has. People who receive our software maintain all freedoms. I have seen over the years many GPL licensed projects change to some more permissive license. Once they did so, the success of the project improved. They had greater buy in, and an increase in use. It increased the size of the open source community and an increase in the code base of an open source project. These are good things. Here I will let it rest. I don't know what else can be expressed to help clarify both sides. Jimmie On 09/22/2017 03:27 AM, Hilaire wrote: > The appropriate and neutral term to describe GPL licence is "recursive". > > GPL licence was designed to build a better computing community, where > freedom is 1st consideration, even at the expense of a lower acceptance. > > Hilaire > > > Le 20/09/2017 Ã 21:30, Jimmie Houchin a Ã©critÂ : >> So my question to you. What words would you use instead of viral and >> infection that equally describe that characteristic of the GPL and >> variants? >

Sept. 25, 2017

Re: [Pharo-users] Is a non-break space whitespace?

by stephan

On 25-09-17 09:53, Richard Sargent wrote: > Rather than off-the-cuffing anything, please honour the Unicode Character > Properties. Refer to > https://en.wikipedia.org/wiki/Unicode_character_property#Whitespace, among > others. That is a good idea. And it won't help you if you scrape data from the web, as you'll find plenty of bad encoding. And unclarity over which version of which standard was used (see mongolian vowel separator) Stephan

Sept. 25, 2017

Re: [Pharo-users] How to find if a method is being executed in a given process

by Steven Costiou

Le 2017-09-25 12:21, jtuchel(a)objektfabrik.de wrote : > Steven > > You could add use a semaphore if changing code is an option. > We once used MethodWrappers in VAST to answer a similar question regarding whether a body of code can be removed from a system. > > Joachim This is exactly my usecase, i need to remove code that may be called by a method on the stack - and i know exactly which method. However my base hypothesis is that it is in an already running process (maybe a loop) and that part i cannot change. Is there an existing Pharo implementation of MethodWrappers ? Le 2017-09-25 14:32, Ben Coman wrote : > I'm not sure if your wanting something more built in, or just "some way", > > so for the latter, consider wrapping in with your own status flags... > > status := #setup. > watcher := [[true] whileTrue:[ > Transcript crShow: status. > 900 milliSeconds wait] > ] forkAt:36. > result := 0. > worker := [[true] whileTrue:[ > status := #WORKING. > 1 second wait. > result := result + 1. > Transcript crShow: result. > status:=#waiting. > 3 seconds wait] > ] forkAt:35. > worker suspend. > worker resume. > > cheers -ben I want to avoid adding control in the code, because hypothetically the process i want to check is already running and possibly written by somebody else. I've think about a similar solution using metalinks, but if the loop is on the stack then i don't know what i can do. Le 2017-09-25 12:42, Marcus Denker a wrote : > you could iterate all processes, there then get the stack and look up the sender chain > if the method is somewhere to be found. If yes -> it is exectuted right now. > One problem is that which methods are on the stack changes, so you should > try to avoid process switches while doing the analysis. > > Marcus Ok so if i know which process to analyse, i can just do something like the following that i found in the Halt class: [ cntxt isNil ] whileFalse: [ cntxt selector = aSelector ifTrue: [ ... ]. cntxt := cntxt sender ] But if i actually found the method i was looking for on the stack, can i somehow ask the suspended context to "execute" until it returns from this method ? Steven.

Sept. 25, 2017

Testing a Unicode Character's Category

by Prof. Andrew P. Black

The Pharo image has a table of Unicode Character Categories in a class variable GeneralCategory of class Unicode. But there do not seem to be many methods to interpret this data. For example, while there is a method Unicode class >> #isDigit: aCharacter that checks if the Unicode category of aCharacter is Nd, and Unicode class >> #isLetter: aCharacter that checks if aCharacter is in one of the letter categories, there does not seem to be a general way of asking âwhat is the category of this characterâ. I want to check if a character is a mathematical symbol, that is, if it is in the Unicode Category Sm. Whatâs the right way of doing this? Would it be reasonable to add a method Unicode class >> #category: aCharacter that answers one of the 29 category symbols #Cc to #Zs? Or âisâ methods for each category? Andrew

Sept. 25, 2017

Re: [Pharo-users] How to find if a method is being executed in a given process

by Ben Coman

On Mon, Sep 25, 2017 at 6:06 PM, Steven Costiou <steven.costiou(a)kloum.io> wrote: > Hi, > > how can i know if a given method is being executed ? > > For ex.: > > process := [[mycondition] whileTrue:[ myObject doStuff. myDelay wait]] fork > > I want to suspend process and find if doStuff is being executed or if > process is waiting. > I'm not sure if your wanting something more built in, or just "some way", so for the latter, consider wrapping in with your own status flags... status := #setup. watcher := [[true] whileTrue:[ Transcript crShow: status. 900 milliSeconds wait] ] forkAt:36. result := 0. worker := [[true] whileTrue:[ status := #WORKING. 1 second wait. result := result + 1. Transcript crShow: result. status:=#waiting. 3 seconds wait] ] forkAt:35. worker suspend. worker resume. cheers -ben

Sept. 25, 2017

Re: [Pharo-users] Is a non-break space whitespace?

by Ben Coman

On Mon, Sep 25, 2017 at 3:53 PM, Richard Sargent < richard.sargent(a)gemtalksystems.com> wrote: > Ben Coman wrote > > On Sun, Sep 24, 2017 at 7:53 PM, PBKResearch < > > > peter@.co > > > > > > wrote: > > > >> Hello All > >> > >> > >> > >> I have a little puzzle to disturb your Sunday lunch, maybe. I have been > >> scraping text data from web pages, which often comes with redundant > space > >> before or after. I routinely use âtrimâ on the final string output, but > I > >> have found cases where there are still redundant spaces. Inspecting the > >> results, I find that the characters are non-break spaces (codepoint 160, > >> Unicode U+00A0). Looking at the code, String>>#trim depends on > >> Character>>#isSeparator, which does not answer true for a non-break > >> space. > >> I can use trimBoth: [:char| char asInteger = 160] to remove the > redundant > >> spaces if I know where to expect them, so it is not a major problem. But > >> the question remains: should non-break space be included in the list of > >> separators in Character>>#isSeparator. > >> > >> > >> > >> Peter Kenny > >> > >> > >> > > > > Off the cuff.. intuitively "by definition" a Non-Break space seems to be > > Not-a-Separator. > > If the web pages you are scraping are misusing non-break space to munge > > formatting, that is not something to be solved by modifying semantics of > > #isSeparator. > > Stef's suggestion for a selector that takes a list of separators seems > > appropriate. > > > Rather than off-the-cuffing anything, please honour the Unicode Character > Properties. Refer to > https://en.wikipedia.org/wiki/Unicode_character_property#Whitespace, among > others. > I hope it was clear I wasn't speaking from a position of authoritative knowledge.. Nice to learn something new. Thanks for the correction. cheers -ben

Sept. 25, 2017