Squeak-dev February 2003

squeak-dev@lists.squeakfoundation.org

195 participants
766 discussions

RE: Traits prototype image
by Brent Vukmer 04 Feb '03

04 Feb '03

Nathanael, thanks for releasing your work out into the wild! This looks really, really cool. -----Original Message----- From: Nathanael Schärli [mailto:n.schaerli@gmx.net] Sent: Tuesday, February 04, 2003 8:38 AM To: squeak-dev(a)lists.squeakfoundation.org Subject: Traits prototype image Hi I finally released a first version of our trait prototype image. More information can be found at: http://www.iam.unibe.ch/~schaerli/smalltalk/traits/traitsPrototype.htm There, you can also read more about our future plans and why there is no changeset available yet. Cheers, Nathanael

1 0

Problems with Collection again.
by Janet Abdul-Karim 04 Feb '03

04 Feb '03

I made an instance of collection and trying to print out what is in the collection. The way I coded seems to only print out the last obect that I added. code portfolio: aAccount portfolio:= SortedCollection new. portfolio sortBlock:[:x :y | x name < y name]. portfolio add: aAccount. code to print portfolio portfolio isNil ifTrue:[Transcript show: 'Portfolio empty']. ifFalse:[portfolio do:[:element | Transcript show: element name]]. ***if you are wondering y i did not use isEmpty instead I tried and it was giving me errors turned out isNil worked just fine. That fact that I could not use isEmpty make me wonder is porfolio is really a collection.*** --------------------------------- Do you Yahoo!? Yahoo! Mail Plus - Powerful. Affordable. Sign up now

3 2

Re: HTF do I post to the list ?
by cg＠cdegroot.com 04 Feb '03

04 Feb '03

Edmund Ronald <squeak-dev(a)lists.squeakfoundation.org> said: >I am using my university acct to gateway, and it is a linux cluster so of >course the names of the machines do not mean much ... HTF do I post to the >list ? > You *must* use a single email address. Do whatever that takes (I operate a webmail service ;-)). -- Cees de Groot http://www.cdegroot.com <cg(a)cdegroot.com> GnuPG 1024D/E0989E8B 0016 F679 F38D 5946 4ECD 1986 F303 937F E098 9E8B Cogito ergo evigilo

1 0

Re: Closures
by Richard A. O'Keefe 04 Feb '03

04 Feb '03

shane(a)shaneroberts.com wrote: [asking about block closures; I'll let others answer that] Also, for years in the 80s and early 90s, any references I read regarding Smalltalk stated that it was too inefficient and not useful for practical applications. I once flew to Los Angeles where I had an appointment to evaluate a Xerox Dolphin workstation running Smalltalk. This was about 1983, and I believe the Dolphin was priced at upwards of $100,00.00. I requested a small example of Smalltalk programming. The representative was tentative about what sort of example to show me, so I said, "How about a simple loop that prints numbers from 1 to 1000." So a loop was written and executed. It never got to 1000, it was TOO SLOW! That about cinched it for me. Xerox Dolphins were rather slow machines. In about 1987 someone at Xerox PARC told me that I should really _really_ ask to see Smalltalk on a Dorado, and for many years the Smalltalk benchmark reference was "one Dorado". The same person told me that Xerox priced Dolphins rather high because they really didn't want to sell any. The phrase "hand-built by leprechauns" was used. The faster Dandelions (and later Dandetigers) were basically 16 bit hardware. At least in Interlisp-D, every time you picked up a cell from memory, it actually took *3* memory references, one 16-bit reference to a page table and then two 16-bit memory references to access the actual data. At may have been the same in ST-80 on a Dolphin? I worked on Xerox Quintus Prolog, which ran pleasantly fast under Interlisp-D on 1108s (Dandelions) although the 1109 was better. The window system was a breeze to use and felt quite responsive. Xerox had some really inventive system and hardware designers. What they *didn't* have, in my view, was any serious intention of selling machines or software. They would not let us (Quintus) sell direct to their customers, nor did we get a chance to talk to their salesmen to explain to them what XQP was or who might be interested in buying it or what for. The net result was that (a) Xerox paid Quintus several millions of dollars to port QP to the D-machines, (b) a major Quintus development was held up for about 18 months in order to meet the letter of the contract, and (c) Xerox sold almost no copies of the software. It wasn't so much that Xerox weren't serious about selling as that they were serious about NOT selling. So I think the botched demo of Smalltalk on a Dolphin actually tells us very little about Smalltalk at ANY stage of its development. Maybe someone at Xerox was just scared that you might try to buy something if they gave you a good demo. I couldn't figure out how you would "share programs" or separate out "data files." You share programs the same way you share C programs across different architectures: as source code (change sets). Data files are as separate as you want them to be, and were back in 1980. Squeak ImageSegments let data files be collections of objects, but text and byte data streams have been around for yonks.

2 1

Re: Add to a collection
by Richard A. O'Keefe 04 Feb '03

04 Feb '03

Janet Abdul-Karim <jn_karim(a)yahoo.com> wrote: I have made an instance instead of inheritence. Good. when i try to print using transcript show it display all the objects only the last one. Is there a way for me to return every single object in the instance using transcript show: I am having a bit of trouble understanding that. The Transcript is a place where you can display text. It is not the ONLY place where you can display text. The normal way to see what is inside an object, at least for debugging purposes, is to use "inspect" or "explore". For small objects, you might "print" it. 1. Open a workspace. 2. Type #((a) (b c d) (e f)) Do NOT type a newline. 3. Press and hold Option on the keyboard; while the option key is down, press and hold the mouse button. On the menu, you see Do it (d) Print it (p) Inspect it (i) Explore it (I) Select the "Print it" line and release the mouse. You will see that the text #(#(#a) #(#b #c #d) #(#e #f)) is added to your text line and highlighted. 4. Press the Delete key to make the new text go away. 5. Press and hold the Command key; while the Command key is down, press and release the 'p' key. You will see that the text #(#(#a) #(#b #c #d) #(#e #f)) is added to your text line and highlighted. When you have typed an expression and it is on one line, or it is anywhere and you have selected that text, Squeak can evaluate it and insert its value in text form after it. Now you know two ways to do that. 6. Press the Delete key again. 7. Now, either by using the option-mouse menu and selecting 'Inspect it', of by just typing Command-i (lower-case i), use the inspector to look at this array. You get a window that looks like [X # Array # O] -------------------------------- |self | | |all inst var| | |1 | | |2 | | |3 | | -------------------------------- | | | | -------------------------------- The bottom pane is basically a mini-workspace where you can type expressions and have them evaluated (do it, print it, inspect it, explore it). The special thing is that in that bottom pane 'self' is the object you are exploring. The title bar tells you what kind of object you are looking at. The other things in the title bar are the usual controls. The top left pane always has 'self' (the object being inspected) and 'all inst var' (all instance variables). For most objects, you will see the individual instance variable names next. For indexed collections, you will see the indices. Select 'self' and the textual representation (self printstring) of the object will be displayed in the top right pane. Select '2' and the textual representation of the 2nd element will be displayed in the top right pane. When you have something selected in the top left pane, option-menu lets you inspect or explore what you have selected. 8. When you have finished playing with that example, click on the X of the title bar to make the inspector go away. 9. 'Explore' is like 'inspect' but basically gives you a 'tree' view of the object you are exploring. It's particularly nice for this example, and may suit your needs. Again, the bottom pane is a mini-workspace, where the thing you have selected is bound to 'self'. The reason why I've gone through this mini-tutorial is that if you want to debug your code by (amongst other things) looking at the object to see if the state is right, then there isn't much point in printing things to the transcript. Use 'explore it' or 'inspect it'. This WILL let you see "every single object in the instance", and it is a much better way than using the transcript. Why is it better than using the transcript? Because you can _interact_ with the object you are looking at; you can easily send queries to bits of it to probe its state further.

1 0

Re: Problems with Collection again.
by Richard A. O'Keefe 04 Feb '03

04 Feb '03

Janet Abdul-Karim <jn_karim(a)yahoo.com> wrote: I made an instance of collection and trying to print out what is in the collection. The way I coded seems to only print out the last obect that I added. We're missing a lot of context here. Object subclass: #Portfolio instanceVariableNames: 'accounts ' ... All I'm concerned with here is 'accounts'. There is other information one might have about a portfolio, such as who owns it, who manages it, its current value, &c. code portfolio: aAccount portfolio:= SortedCollection new. portfolio sortBlock:[:x :y | x name < y name]. portfolio add: aAccount. This is confusing. A portfolio is not an account, and adding an account is not the same as setting a portfolio. Why is a SortedCollection used? SortedCollections are costly (one might even say _very_ costly) to update. A variant of SortedCollection using some kind of balanced binary search tree might be nice to have, but SortedCollection itself is not such a data structure. Let's use self-encapsulation to access 'accounts', and within that, let's use lazy initialisation. This way, the rest of the system NEVER sees a nil account collection. accounts accounts ifNil: [ accounts := SortedCollection new. accounts sortBlock: [:x :y | x name < y name]]. ^accounts Now if we ask for (aPortfolio accounts size) we don't have to worry about nil. addAccount: anAccount ^self accounts add: anAccount Now thing slike (aPortfolio addAccount: anAccount) will work fine, albeit slowly (order N). code to print portfolio portfolio isNil ifTrue:[Transcript show: 'Portfolio empty']. ifFalse:[portfolio do:[:element | Transcript show: element name]]. ***if you are wondering y i did not use isEmpty instead I tried and it was giving me errors turned out isNil worked just fine. That fact that I could not use isEmpty make me wonder is porfolio is really a collection.*** Why bother with this at all? Why not just "inspect" or "explore" a Portfolio instance? Or do this: printOn: aStream |sep| aStream nextPutAll: 'a Portfolio '. sep := $(. self accounts do: [:each | aStream nextPut: sep. each name printOn: aStream. sep := Character space]. aStream nextPut: $). and then Transcript show: aPortfolio printString; cr.

1 0

Re: Add to a collection
by Richard A. O'Keefe 04 Feb '03

04 Feb '03

Janet Abdul-Karim <jn_karim(a)yahoo.com> wrote: I created a subclass to ordered collections. Unless you are inventing a new kind of collection data structure, you probably don't want to do that. We could have hours of fun debating whether a portfolio *is* a collection of accounts or *has* a collection of accounts, but the simplest way to look at it may be this: If your class INHERITS from Collection, then (a) you have the obligation to make sure that all of the methods in the interface of Collection WORK for your class, or are explicitly cancelled. Collection is pretty big in Squeak, you probably don't want to do that. (b) you inherit EVERYTHING from Collection, including methods that change the object in ways you probably don't want to happen. I am trying to add objects to the new class Presumably you mean "add objects to AN INSTANCE OF the new class". and then print it to make sure they are in there. Good. I add one object it prints but when I add another object and print it only prints the first object i added sample code to add to list. account: aAccount "Add an account to the portfolio" self isNil ifTrue:[self add: aAccount] ifFalse:[ self addLast: aAccount]. The only object for which 'self isNil' can ever be true is nil. nil is the unique instance of UndefinedObject. nil is NOT an instance of your class. Your code can be simplified to addAccount: anAccount self addLast: anAccount. code to print list. accounts "Returns the accounts for the portfolio" self do:[:element|^element number]. (1) That code doesn't print anything. (2) Did you notice that little caret in there? What your code says is "For each element in myself RETURN the element's number STRAIGHT AWAY RIGHT NOW! (and don't look at any other elements)." This is almost the same as ^self first number Change the code to accountNumbers "Answer the account numbers of all the accounts in the portfolio." ^self collect: [:each | each number]

2 1

[FIX] WeekDateFixes-sbw
by swessels＠one.net 04 Feb '03

04 Feb '03

from preamble: "Change Set: date fixes Date: 31 January 2003 Author: Stephan B Wessels By default weeks begin on Monday in Squeak and code exists to toggle between Sunday start and Monday start. This change set adds a explicit setting methods for the start of week day. There were a few places in the code where proper adjustment to Sunday beginning weeks were not correct. The Date #weekday math was corrected to account for Monday/Sunday week start. Month has a new #weeksInMonth method. Week #indexInMonth: method was also fixed. Note that the MonthMorph still works correctly since it coded around this. Wrote some SUnit tests for Date and Week."!

1 0

Squeak fonts
by zeppy＠australia.edu 04 Feb '03

04 Feb '03

Hi! I've noticed that there aren't that many fonts available in Squeak. I would have thought with object technology that it wouldn't be a problem to have more. Why isn't there and how involved is this topic. Cheers! Zeppy This message was sent from http://australia.edu Check out the new international site at http://australia.edu/international

5 4

Re: [ANN] Ma client server
by Chris Muller 04 Feb '03

04 Feb '03

--- Eric Merritt <cyberlync(a)yahoo.com> wrote: > > This looks really cool, is there any way to know > which connection a ByteArray is submitted from? I was > just thinking in terms of authentication > functionality. Yes, the MaServerSocket sends event notifications to its #server (an instance of MaServer, by default) for client sockets all the way through the request/response process. By default, these are ignored, but you can choose to implement some behavior on any one of them, including the accept of a client socket. At this time, the method #noteSocketQueued: aSocket is available to override. The argument is the client Socket, from which you should be able to get the IP or other info. I hope this answers your question. Regards, Chris __________________________________________________ Do you Yahoo!? Yahoo! Mail Plus - Powerful. Affordable. Sign up now. http://mailplus.yahoo.com

1 0

Jump to page: