December 2014 - Pharo-users

Re: [Pharo-users] Question on temporal variables in Workspace

by Sven Van Caekenberghe

> On 28 Dec 2014, at 12:52, kilon alios <kilon.alios(a)gmail.com> wrote: > > "You figured out how to use it, yet you did not use the system to search for an explanation ?" > > Do you call me lazy ? Hmm, I was only provoking you a little bit ;-) What I meant is: it was a actually explained in the class comment, which is the first place to look for information. I know they are not all good, but at least here the thing you wanted to know was mentioned. Second, the whole idea of Pharo is that you can explore the system using the tools given. I was just suggesting how you would/could do that. I did the same thing before writing the mail. Of course, you do not have to read everything from beginning to end, no one would want to do that. You just start looking for specific information, poke the system. Once you get the hang of it, it is really cool and powerful. There are some Pharo contributors who are amazingly good at this, fixing issues that must be new to them. Sven

Dec. 28, 2014

Re: [Pharo-users] Question on temporal variables in Workspace

by kilon alios

"You figured out how to use it, yet you did not use the system to search for an explanation ?" Do you call me lazy ? where you based this assumption ? I have looked in the past on the comment of the Workspace class but I dont find an adequate (as most class comments inside Pharo) to explain the inner workings of Workspace. Also I dont have the time ( I can only spare one hour a day ) to study the entire source code of Pharo , I read code only on the "need to know basis". I never felt the need to know how workspace variables work internally and whats their difference with temporary variables. "Check the references to the instance variable 'bindings' of Workspace." if you read my post you would have noticed I have already done that. Unless you mean something else ? Also the title of this thread is "Temporary Variables" , I dont see you mentioning them anywhere . "When evaluating code (do it, inspect it, print it) the expression is compiled. Compilation happens in a context. For scripting code this is often nil, but Pharo (method code) normally references an object (self). So when evaluating from a Workspace, the workspace instance with its bindings is used as context. So, these variables are local to the workspace, but behave a bit like a mixture between global and instance variables." I don't know how Nacho feels about this but I cant say it makes it clear for me how workspace variables vs workspace temporary variables work exactly. I have read about Squeak compilation model somewhere and the importance of thisContext , so I think I understand at least vaguely how this works. I have to say I find the term "scripting" perplexing. Scritping for me is coding that allows one to manipulate an application, but Pharo is more like a development enviroment so I dont see how it would be possible to do scripting inside Pharo using the pharo language.

Dec. 28, 2014

Re: [Pharo-users] [squeak-dev] From Smalltalk to Squeak by Dan Ingalls at CHM 10/11/2001 (VPRI 797)

by Trygve Reenskaug

On 25.12.2014 01:22, Yoshiki Ohshima wrote: > A holiday present from the past! I digitized a video tape that VPRI > has and uploaded: > http://youtu.be/4ki2AQvneD8 > > Hope you enjoy it! > Dear Dan, Thank you for taking the trouble to record the history of Smalltalk history; I think it is both interesting and important to understand how the Smalltalk technology evolved. I hear you refer to Smalltalk as a programming language. Most of the programmers I know will misunderstand this. To them, a program is a text written in a programming language. The text is the Real Thing, the executable is derived. Contrast with Alan's definition of object orientation: Objects are like computers communicating through a very fast network. With Smalltalk, communication became a first class citizen of computing. The Real Thing is now a universe of communicating objects. Objects are mustered on the fly to perform a task. There is no "Smalltalk Language" in the common sense of the word. It is true that Smalltalk releases have a default language for compiling methods within a class. The compiler is private to the class; other classes may use different compilers and, therefore, different languages. For example, VisualWorks had a class where the methods were written in SQL. My main objection to calling Smalltalk a programing language is that it belittles its importance. IMO, Alan's concept of object orientation that is reified in Smalltalk is the the most important software invention since the first programming languages in the 1950s. It heralds an entirely new way of thinking about computing by replacing the underlying digital computer with a universe of communicating entities. I call it an /object computer/. (I see signs of this idea cropping up in other contexts as for example in "Unikernels: Rise of the Virtual Library Operating System <http://queue.acm.org/detail.cfm?id=2566628>"). We are only scratching the surface of the object computer's capabilities. I hope we in the coming years will deepen our understanding of what this invention entails and create powerful ways to exploit it. Squeak and its derivatives give us a flying start. I wish you all a productive and Happy New Year --Trygve -- Trygve Reenskaug mailto: trygver(a)ifi.uio.no Morgedalsvn. 5A http://folk.uio.no/trygver/ N-0378 Oslo http://fullOO.info Norway Tel: (+47) 22 49 57 27

Dec. 28, 2014

Re: [Pharo-users] Question on temporal variables in Workspace

by Sven Van Caekenberghe

Kilon, You figured out how to use it, yet you did not use the system to search for an explanation ? >From the class comment of Workspace: === A workspace can have its own variables, called "workspace variables", to hold intermediate results. For example, if you type into a workspace "x := 5" and do-it, then later you could type in "y := x * 2" and y would become 10. === In the window menu of Workspace you have 'Inspect variables', 'Reset Variables'. Check the references to the instance variable 'bindings' of Workspace. Check the senders of #bindingOf: Summary: When evaluating code (do it, inspect it, print it) the expression is compiled. Compilation happens in a context. For scripting code this is often nil, but Pharo (method code) normally references an object (self). So when evaluating from a Workspace, the workspace instance with its bindings is used as context. So, these variables are local to the workspace, but behave a bit like a mixture between global and instance variables. HTH, Sven > On 28 Dec 2014, at 09:32, kilon alios <kilon.alios(a)gmail.com> wrote: > > I am not familiar with that part of Pharo because I never use temporary variables in Workspace but I did a little experiment and this is what I found . I followed these 3 steps > > 1) I created 2 Workspaces > 2) In first Workspace I put the code > > |a| > a:= Morph new. > a openInWindow . > > 3) In the second Workspace I put the code > > a:= Morph new. > a openInWindow . > > Now executing both examples give the result you would expect , a morph inside a window BUT if I inspect variable a in both cases , the workspace variable example returns me a Morph as to be expected on the other hand the workspace temporary variable returns me an undefined object. So that leads me to assume here that the temporary variable works as expect by destroying its reference as soon as the code is executed, hence why its called "temporary ;) > > > > On Sat, Dec 27, 2014 at 9:28 PM, nacho <0800nacho(a)gmail.com> wrote: > Hi pharoers, > In killion video tutorials I see that he uses variables not declaring them > as temporal (that is | aVariable | ). > If one does not declare variables as temporal in a workspace what kind of > variables are them? > Also why in the tutorial they appear in blue and in my workspace they appear > in red as if there was something wrong? (actually if I declare all variables > as temporal using | | then all turn tu blue). > Thanks in advance and best regards > Nacho > > > > > ----- > Nacho > Smalltalker apprentice. > Buenos Aires, Argentina. > -- > View this message in context: http://forum.world.st/Question-on-temporal-variables-in-Workspace-tp4797161… > Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com. > >

Dec. 28, 2014

Re: [Pharo-users] Traveling to PharoDays

by Marcus Denker

> On 28 Dec 2014, at 09:41, Joachim Tuchel <jtuchel(a)objektfabrik.de> wrote: > > Interesting. A EU citizen flying from Munich to Brussels on transit to Paris has to be checked at the Belgian/French Border? > Only if you take the EUROSTAR to London and exit in Lille. They check everyone in Brussels. The alternative would be to either not allow people to exit in Lille or to get everyone off in Lille and have a 1-2 hour brake rechecking everyone. These days they normally do not sell tickets anymore for the eurostar to exit in Lille (to speed up the stop in Lille I think). Marcus

Dec. 28, 2014

Re: [Pharo-users] Traveling to PharoDays

by Joachim Tuchel

Interesting. A EU citizen flying from Munich to Brussels on transit to Paris has to be checked at the Belgian/French Border? But I absolutely buy into your connection argument for Brussels Airport... Unfortunately, I will not have time to come to Pharo Days 2015. I hope some sessions willbe recorded. Not a replacement for the networking... Joachim stepharo <stepharo(a)free.fr> schrieb: > >Le 27/12/14 14:08, Joachim Tuchel a Ã©crit : >> Doesn't the Thalys from Brussels to Paris stop in Lille? > >Yes it does. >Now you have to pay attention that you have to be really on time because >you have to pass a scan with your luggages and a border check. >I tend to avoid to take it because this is not fun. > > >> ClÃ©ment Bera <bera.clement(a)gmail.com> schrieb: >> >> There's a direct train from Paris CDG airport to Lille. It's usually >> more complex to go from brussels airport to Lille. >> >> There's an airport in Lille but there's very few flights from there >> (only to Marseilles and Porto AFAIK). >> >> 2014-12-27 12:21 GMT+01:00 Udo Schneider <udo.schneider(a)homeaddress.de >> <mailto:udo.schneider@homeaddress.de>>: >> >> All, >> >> what's the best international Airport to reach Lille? I'm >> currently thinking of flying to Brussels and take a train from >> there? Any other recommendations? >> >> CU, >> >> Udo >> >> >> >

Dec. 28, 2014

Re: [Pharo-users] Traveling to PharoDays

by Marcus Denker

> On 28 Dec 2014, at 09:14, stepharo <stepharo(a)free.fr> wrote: > > > Le 27/12/14 14:08, Joachim Tuchel a Ã©crit : >> Doesn't the Thalys from Brussels to Paris stop in Lille? > > Yes it does. > Now you have to pay attention that you have to be really on time because you have to pass a scan with your luggages and a border check. > I tend to avoid to take it because this is not fun. > No, that is the Eurostar. (the train to london). For Thalys, the Cologne->Brussels->Paris line does *not* stop in Lille, but there is a new Amsterdam->Brussels->Lille Thalys that does. Marcus

Dec. 28, 2014

Re: [Pharo-users] Question on temporal variables in Workspace

by kilon alios

I am not familiar with that part of Pharo because I never use temporary variables in Workspace but I did a little experiment and this is what I found . I followed these 3 steps 1) I created 2 Workspaces 2) In first Workspace I put the code |a| a:= Morph new. a openInWindow . 3) In the second Workspace I put the code a:= Morph new. a openInWindow . Now executing both examples give the result you would expect , a morph inside a window BUT if I inspect variable a in both cases , the workspace variable example returns me a Morph as to be expected on the other hand the workspace temporary variable returns me an undefined object. So that leads me to assume here that the temporary variable works as expect by destroying its reference as soon as the code is executed, hence why its called "temporary ;) On Sat, Dec 27, 2014 at 9:28 PM, nacho <0800nacho(a)gmail.com> wrote: > Hi pharoers, > In killion video tutorials I see that he uses variables not declaring them > as temporal (that is | aVariable | ). > If one does not declare variables as temporal in a workspace what kind of > variables are them? > Also why in the tutorial they appear in blue and in my workspace they > appear > in red as if there was something wrong? (actually if I declare all > variables > as temporal using | | then all turn tu blue). > Thanks in advance and best regards > Nacho > > > > > ----- > Nacho > Smalltalker apprentice. > Buenos Aires, Argentina. > -- > View this message in context: > http://forum.world.st/Question-on-temporal-variables-in-Workspace-tp4797161… > Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com. > >

Dec. 28, 2014

Re: [Pharo-users] Traveling to PharoDays

by stepharo

Le 27/12/14 14:08, Joachim Tuchel a Ã©crit : > Doesn't the Thalys from Brussels to Paris stop in Lille? Yes it does. Now you have to pay attention that you have to be really on time because you have to pass a scan with your luggages and a border check. I tend to avoid to take it because this is not fun. > ClÃ©ment Bera <bera.clement(a)gmail.com> schrieb: > > There's a direct train from Paris CDG airport to Lille. It's usually > more complex to go from brussels airport to Lille. > > There's an airport in Lille but there's very few flights from there > (only to Marseilles and Porto AFAIK). > > 2014-12-27 12:21 GMT+01:00 Udo Schneider <udo.schneider(a)homeaddress.de > <mailto:udo.schneider@homeaddress.de>>: > > All, > > what's the best international Airport to reach Lille? I'm > currently thinking of flying to Brussels and take a train from > there? Any other recommendations? > > CU, > > Udo > > >

Dec. 28, 2014

Re: [Pharo-users] Question on temporal variables in Workspace

by stepharo

> I am a bit new to Pharo, anyone please correct me if I am wrong. excellent initiative. Explaining is an excellent way to learn. > The Workspace has a #mustDeclareVariables: method. I am assuming it is set to false by default. > The colour changes once you DoIt on the code, as the variable is automatically created and bound to the workspace, so after running once, it exists. You can see this as the first time when you try inspect a variable, an error occurs. After DoIt, it changes colour, and you can inspect it. > > Cheers, > -Edward

Dec. 28, 2014