Beginners January 2014

beginners@lists.squeakfoundation.org

14 participants
8 discussions

Re: Beginners Digest, Vol 93, Issue 1: object instance browser
by David Holiday 12 Aug '14

12 Aug '14

Thank you everyone for your alacritous responses! I'm finding one of the challenges in learning Smalltalk is not the syntax of the code, nor the general paradigm by which the code is implemented, but understanding the tools well enough to make things happen. I'm an experienced programmer and I'm finding that I'm having to completely rethink the way I go about my work when diddling around with this language. That's not in and of itself a bad thing - just saying I'm thankful for this mailing list :-) David Holiday ------------------------------------------------- San Diego State University neuburge(a)rohan.sdsu.edu On Jan 1, 2014, at 4:00 AM, beginners-request(a)lists.squeakfoundation.org wrote: > Send Beginners mailing list submissions to > beginners(a)lists.squeakfoundation.org > > To subscribe or unsubscribe via the World Wide Web, visit > http://lists.squeakfoundation.org/mailman/listinfo/beginners > or, via email, send a message with subject or body 'help' to > beginners-request(a)lists.squeakfoundation.org > > You can reach the person managing the list at > beginners-owner(a)lists.squeakfoundation.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Beginners digest..." > > > Today's Topics: > > 1. Re: object instance browser? (Herbert K?nig) > 2. Re: object instance browser? (Chris Muller) > 3. Re: object instance browser? (karl ramberg) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Tue, 31 Dec 2013 14:50:55 +0100 > From: Herbert K?nig <herbertkoenig(a)gmx.net> > Subject: Re: [Newbies] object instance browser? > To: beginners(a)lists.squeakfoundation.org > Message-ID: <52C2CBBF.6050801(a)gmx.net> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed > > Merci vielmals. > > Am 31.12.2013 11:27, schrieb Bert Freudenberg: >> Yes, multiple ones in fact. This is a major reason working in >> Smalltalk feels more immediate than in other environments. > ...... > Great explanation scrubbed > > > ------------------------------ > > Message: 2 > Date: Tue, 31 Dec 2013 13:02:51 -0600 > From: Chris Muller <asqueaker(a)gmail.com> > Subject: Re: [Newbies] object instance browser? > To: "A friendly place to get answers to even the most basic questions > about Squeak." <beginners(a)lists.squeakfoundation.org> > Message-ID: > <CANzdToH+hPyJqeBqSdWLwROi5w_SbdAu_G9oWm3BgRkTqa=z9w(a)mail.gmail.com> > Content-Type: text/plain; charset=UTF-8 > > Great post, I learned some new things. > > On Tue, Dec 31, 2013 at 4:27 AM, Bert Freudenberg <bert(a)freudenbergs.de> wrote: >> On 31.12.2013, at 08:53, David Holiday <neuburge(a)rohan.sdsu.edu> wrote: >> >>> Is there a way to browse the ecosystem of objects in a Smalltalk image? >> >> Yes, multiple ones in fact. This is a major reason working in Smalltalk feels more immediate than in other environments. >> >>> I'm not talking about the class browser, what I'm looking for is a way to see what objects have actually been instantiated and what their state is. >> >> The basic tool for this is called an Inspector. Whenever you have an expression, like "3 + 4", you press cmd-i to "inspect it", which opens an inspector on the result. This works in any text area. Try for example inspecting "self" in a class browser, and you will inspect the underlying class object (which the browser shows a high-level view of). >> >> In the Inspector you see the objects referenced by this object (via instance variables or indexed fields) in the left panel. Select any of them and choose "inspect" from the context menu (or press cmd-i again). This way you can inspect all the objects in the system. >> >> A more modern tool than the Inspector (which was around 40 years ago already) is the Object Explorer. It presents you a tree view of an object and its "children", which again are the instance variables and indexed fields of the object. Open it with cmd-shift-i (or "explore" in the context menu). >> >> You can also do the reverse. If you choose "objects pointing to this value" you get an inspector showing all the objects that directly point to this object. Similarly there is a "reverse explorer", which you can open by selecting "explore pointers". >> >> There are two roots to all the objects in the system: >> >> Smalltalk specialObjectsArray >> >> which basically holds everything the Virtual Machine needs to know about, and in turn almost every object in the whole image, and >> >> thisContext >> >> which is the current execution context, holding onto temporary objects. When a garbage collection is performed, any object not reachable form either of these two roots is removed from memory. >> >> An "interesting" global object to explore is >> >> Project current >> >> which holds your current workspace, in particular >> >> Project current world >> >> , the root of all morphs in the world. And of course >> >> Smalltalk >> >> itself is the dictionary that holds all global objects, including all classes (unless they are defined in a non-global environment). >> >> There is also a low-level way to enumerate all objects in memory. "self someObject" will return the very first object in memory (which happens to be the nil object), and "anObject nextObject" will return the next one: >> >> | object count | >> count := 0. >> object := self someObject. >> [0 == object] >> whileFalse: [count := count + 1. >> object := object nextObject]. >> count >> >> Interestingly, this also finds objects that are due to be garbage-collected. For example, if you accidentally closed a text window, there is a good chance its contents will still be in memory, and can be retrieved using an expression like >> >> ByteString allInstances last: 10 >> >> This makes use of the someInstance/nextInstance methods, which are similar to someObject/nextObject, but restricted to instances of one class only. >> >> Hope you have fun poking around in the world of objects :) >> >> - Bert - >> >> >> _______________________________________________ >> Beginners mailing list >> Beginners(a)lists.squeakfoundation.org >> http://lists.squeakfoundation.org/mailman/listinfo/beginners > > > ------------------------------ > > Message: 3 > Date: Wed, 1 Jan 2014 02:23:04 +0100 > From: karl ramberg <karlramberg(a)gmail.com> > Subject: Re: [Newbies] object instance browser? > To: "A friendly place to get answers to even the most basic questions > about Squeak." <beginners(a)lists.squeakfoundation.org> > Cc: David Holiday <neuburge(a)rohan.sdsu.edu> > Message-ID: > <CAGzzWLgJCGf1AkddemfwwvsRtfaHoHO5R+mRPu5eR4ZQy+iFfw(a)mail.gmail.com> > Content-Type: text/plain; charset="iso-8859-1" > > I do it :-) > > Happy new year! > > Cheers, > Karl > > > On Tue, Dec 31, 2013 at 12:40 PM, Bert Freudenberg <bert(a)freudenbergs.de>wrote: > >> Hey, I wrote it, you make the workspace, deal? ;) >> >> Happy New Year, btw. >> >> - Bert - >> >> On 31.12.2013, at 12:37, karl ramberg <karlramberg(a)gmail.com> wrote: >> >> Make a Welcome Workspace with this info :-) >> >> Cheers, >> Karl >> >> >> On Tue, Dec 31, 2013 at 11:27 AM, Bert Freudenberg <bert(a)freudenbergs.de>wrote: >> >>> On 31.12.2013, at 08:53, David Holiday <neuburge(a)rohan.sdsu.edu> wrote: >>> >>>> Is there a way to browse the ecosystem of objects in a Smalltalk image? >>> >>> Yes, multiple ones in fact. This is a major reason working in Smalltalk >>> feels more immediate than in other environments. >>> >>>> I'm not talking about the class browser, what I'm looking for is a way >>> to see what objects have actually been instantiated and what their state is. >>> >>> The basic tool for this is called an Inspector. Whenever you have an >>> expression, like "3 + 4", you press cmd-i to "inspect it", which opens an >>> inspector on the result. This works in any text area. Try for example >>> inspecting "self" in a class browser, and you will inspect the underlying >>> class object (which the browser shows a high-level view of). >>> >>> In the Inspector you see the objects referenced by this object (via >>> instance variables or indexed fields) in the left panel. Select any of them >>> and choose "inspect" from the context menu (or press cmd-i again). This way >>> you can inspect all the objects in the system. >>> >>> A more modern tool than the Inspector (which was around 40 years ago >>> already) is the Object Explorer. It presents you a tree view of an object >>> and its "children", which again are the instance variables and indexed >>> fields of the object. Open it with cmd-shift-i (or "explore" in the context >>> menu). >>> >>> You can also do the reverse. If you choose "objects pointing to this >>> value" you get an inspector showing all the objects that directly point to >>> this object. Similarly there is a "reverse explorer", which you can open by >>> selecting "explore pointers". >>> >>> There are two roots to all the objects in the system: >>> >>> Smalltalk specialObjectsArray >>> >>> which basically holds everything the Virtual Machine needs to know about, >>> and in turn almost every object in the whole image, and >>> >>> thisContext >>> >>> which is the current execution context, holding onto temporary objects. >>> When a garbage collection is performed, any object not reachable form >>> either of these two roots is removed from memory. >>> >>> An "interesting" global object to explore is >>> >>> Project current >>> >>> which holds your current workspace, in particular >>> >>> Project current world >>> >>> , the root of all morphs in the world. And of course >>> >>> Smalltalk >>> >>> itself is the dictionary that holds all global objects, including all >>> classes (unless they are defined in a non-global environment). >>> >>> There is also a low-level way to enumerate all objects in memory. "self >>> someObject" will return the very first object in memory (which happens to >>> be the nil object), and "anObject nextObject" will return the next one: >>> >>> | object count | >>> count := 0. >>> object := self someObject. >>> [0 == object] >>> whileFalse: [count := count + 1. >>> object := object nextObject]. >>> count >>> >>> Interestingly, this also finds objects that are due to be >>> garbage-collected. For example, if you accidentally closed a text window, >>> there is a good chance its contents will still be in memory, and can be >>> retrieved using an expression like >>> >>> ByteString allInstances last: 10 >>> >>> This makes use of the someInstance/nextInstance methods, which are >>> similar to someObject/nextObject, but restricted to instances of one class >>> only. >>> >>> Hope you have fun poking around in the world of objects :) >>> >>> - Bert - >>> >>> >>> _______________________________________________ >>> Beginners mailing list >>> Beginners(a)lists.squeakfoundation.org >>> http://lists.squeakfoundation.org/mailman/listinfo/beginners >>> >> >> _______________________________________________ >> Beginners mailing list >> Beginners(a)lists.squeakfoundation.org >> http://lists.squeakfoundation.org/mailman/listinfo/beginners >> >> >> >> >> _______________________________________________ >> Beginners mailing list >> Beginners(a)lists.squeakfoundation.org >> http://lists.squeakfoundation.org/mailman/listinfo/beginners >> >> >

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What is Squeak called a "practical" Smalltalk
by Azka Niazi 30 Jan '14

30 Jan '14

Squeak is referred to as a practical Smalltalk. "Practical" must technically mean something. What goals of practicality has Squeak achieved versus other Smalltalks or other programming environment/languages. Regards,Azka

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Read a filestream (named pipe) with a timeout
by dsl101 13 Jan '14

13 Jan '14

I'm using Squeak 4.2 and working on the smalltalk end of a named pipe connection, which sends a message to the named pipe server with: msg := 'Here''s Johnny!!!!'. pipe nextPutAll: msg; flush. It should then receive an acknowledgement, which will be a 32-byte md5 hash of the received message (which the smalltalk app can then verify). It's possible the named pipe server may have gone away or otherwise been unable to deal with the request, and so I'd like to set a timeout on reading the acknowledgement. I've tried using this: ack := [ pipe next: 32 ] valueWithin: (Duration seconds: 3) onTimeout: [ 'timeout'. ]. and then made the pipe server pause artificially to test the code. But the smalltalk thread blocks on the read and doesn't carry on (even after the timeout), although if I then get the pipe server to send the correct response (after a 5 second delay, for example), the value of 'ack' is 'timeout'. Obviously the timeout did what it's supposed to do, but couldn't 'unblock' the blocking read on the pipe. Is there a way to accomplish this even with a blocking FileStream read? I'd rather avoid a busy wait on there being 32 characters available if at all possible. Thanks, Dave -- View this message in context: http://forum.world.st/Read-a-filestream-named-pipe-with-a-timeout-tp4735456… Sent from the Squeak - Beginners mailing list archive at Nabble.com.

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How to use Form pixelCompare:with:at:
by Herbert König 07 Jan '14

07 Jan '14

Hi, Form>>pixelCompare:with:at: seems to always return 0. I use it like |pict1 pict2| pict1 := (Form extent: 100@100 depth: 32) fillBlack. pict2 := (Form extent: 100@100 depth: 32) fillWithColor: Color red. pict1 pixelCompare: pict1 boundingBox with: pict2 at: 0@0 As I get the same result in a 4.4 and a 3.8 image I guess I don't understand how it's used. No senders in either image. Any help is appreciated. Cheers, Herbert

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object instance browser?
by David Holiday 07 Jan '14

07 Jan '14

Is there a way to browse the ecosystem of objects in a Smalltalk image? I'm not talking about the class browser, what I'm looking for is a way to see what objects have actually been instantiated and what their state is. David Holiday ------------------------------------------------- San Diego State University neuburge(a)rohan.sdsu.edu

6 11

Is there a way to broadcast messages to more than one recipient?
by David Holiday 04 Jan '14

04 Jan '14

As far as I can tell, messages have to be directed at a single recipient. Is this the case or, for example, is it possible to blast a message to every member of an Array at the same time? David Holiday ------------------------------------------------- San Diego State University neuburge(a)rohan.sdsu.edu

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Re:[Newbies] A morph for doing 2D plots
by summae3443＠mypacks.net 02 Jan '14

02 Jan '14

Thicker line widths would be useful for some plots. Example: net assets versus time, where several of these piecewise continuous curves are plotted together, each with a distinct color. Each one might have 100 points. Dan -----Original Message----- >From: Mateusz Grotek <unoduetre(a)poczta.onet.pl> >Sent: Jan 1, 2014 3:02 PM >To: "A friendly place to get answers to even the most basic questions about > Squeak." <beginners(a)lists.squeakfoundation.org> >Subject: Re: [SPAM] [Newbies] A morph for doing 2D plots > >summae3443(a)mypacks.net pisze: >> This is very much appreciated. Thank you, Mateusz. >> How can I change the line width used by the relations? >> >> Dan Norton >> >> >> ------------------------------------------------------------------------ >> >> _______________________________________________ >> Beginners mailing list >> Beginners(a)lists.squeakfoundation.org >> http://lists.squeakfoundation.org/mailman/listinfo/beginners > >I don't know exactly what you mean, but I assume you want to make the >relation "line" thicker. In the current version it is impossible, unless >you modify the code. (It's still alpha :-) Do you think it is a useful >feature? >_______________________________________________ >Beginners mailing list >Beginners(a)lists.squeakfoundation.org >http://lists.squeakfoundation.org/mailman/listinfo/beginners

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A morph for doing 2D plots
by summae3443＠mypacks.net 01 Jan '14

01 Jan '14

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Beginners January 2014