Beginners October 2008

beginners@lists.squeakfoundation.org

62 participants
79 discussions

Fileupload
by Riaan van Aarde - Specon Eng 10 Oct '08

10 Oct '08

Is there any way that I can limit fileupload size. I have a "document upload" function, but would like to limit the filesize to about 5mb. Can anyone please assist me.

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How to create new exception
by Alex Chi 10 Oct '08

10 Oct '08

Hi All, As a beginner in smalltalk I have a problem on how to create new exception class. For example I want to create FileNotFoundError, I have create a new class FileNotFoundError uner class Error. But then I get confuse where to write the description or defaultAction of my new exception? Thanks. Regards, Alex Chinoura

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Callback
by xyz 42 09 Oct '08

09 Oct '08

Hello! I want to create a callback that will call my method after, say, 10 minutes. How can I do it in squeak? TIA.

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Re: Best data structure for a multi-dimensional database?
by stephan＠stack.nl 08 Oct '08

08 Oct '08

> Two data structures spring to mind: It depends. How many dimensions do you want to support with how many elements, how many facts, and what kind of calculations do you want to do on those facts? Can you, and do you want to pre-calculate values? Do you need a data structure that can be easily distributed over multiple machines? You could try a btree of the facts with a multi- dimensional index (pairs of low-high values for each dimension). When you have to split a block, you can select a dimension where the number of facts splits reasonably. Build the dimension hierarchy separately. Stephan

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marking a package as installed
by Aidan Gauland 08 Oct '08

08 Oct '08

Hello, I've been trying to install Baloon3D, and I'm stuck on the package VMmaker. I can't get it with my slow dial-up connection, because the server keeps disconnecting me after a while, so I had somebody with a high-speed Internet connection get it for me. Now when I install it with Monticello, the Universe Browser doesn't know that it's installed, and tries to get it anyway (because it's a dependency of Baloon3D). Is there a way I can mark VMmaker as installed for the Universe Browser? Thanks, Aidan

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Best data structure for a multidimensional database?
by stan shepherd 08 Oct '08

08 Oct '08

Hi, I'm looking at building a small proof of concept of a multidimensional modelling tool in Squeak. Commercial products are things like Cognos, and the old Express that was assimilated by Oracle. A typical 'cube' will be 'dimensioned' by product, region, time. Each dimension has one or more roll-ups, e.g. All Ice Creams / \ Cornetto Tub / | \ C. Raspberry C. Vanilla C. Chocolate Then sales data would be entered for the lowest level, then rolled up over the product hierarchy, the region hierarchy, the time hierarchy. >From there, you can ask qusetions like "what's the year on year change in sales of Cornetto for Western Europe". Two data structures spring to mind: 1) Use nested dictionaries for the dimensions, so that from the sales cube we select the dictionary entry for Cornetto, then from there the entry for Western Europe, then the two entries for this year to date and last year to date, being actual numbers. 2) Give each dimension element a numerical index, eg Cornetto is product no 451 in the product dimension. Sales then becomes a single dictionary where we calculate the index as product number + (region number * number of products) + (period number * number of products * number of regions) no 2) sounds faster, but no 1) sounds Squeakier. Does anyone have any advice as to how best to do this? Options 3) etc also welcome. I daresay the correct answer is to do both and see which works best, but I suspect there are some obvious gotchas I'm not seeing. Thanks, Stan -- View this message in context: http://www.nabble.com/Best-data-structure-for-a-multidimensional-database--… Sent from the Squeak - Beginners mailing list archive at Nabble.com.

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substring
by Mark Volkmann 07 Oct '08

07 Oct '08

I can't find a method to give me a substring of a String from a given index to the end. The copyFrom:to: method requires telling it the end. Does a method exist where you only specify the starting point? I know I could write it myself, but I don't want to do that if it's already there. --- Mark Volkmann

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enumerated types
by Mark Volkmann 06 Oct '08

06 Oct '08

Have I summarized this correctly? Smalltalk doesn't support the concept of enumerated types like in Java 5 and above. Instead, the Smalltalk way is to: create a class that represents the enumerated type add a class variable for each enumerated value (must start uppercase) add a class-side initialize method that creates an instance of the class for each enumerated value using basicNew and assigns it the corresponding class variable prevent creation of additional instances by overiding the class method new with "self error: 'new instances cannot be created'" add class-side getter method for each enumerated value that simply returns it Here's an example ColorEnum class. Object subclass: #ColorEnum instanceVariableNames: '' classVariableNames: 'Blue Green Red' poolDictionaries: '' category: 'SomeCategory' initialize Red := self basicNew. Green := self basicNew. Blue := self basicNew new self error: 'new instances cannot be created' red ^Red green ^Green blue ^Blue --- Mark Volkmann

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first use of Monticello
by Mark Volkmann 05 Oct '08

05 Oct '08

I'm trying to save a package to squeaksource for the first time using a Monticello Browser. I get "ConnectionTimedOut: send data timeout; data not sent". I created the project at squeaksource.com already. --- Mark Volkmann

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Re: Beginners Digest, Vol 30, Issue 13
by Charles Bacon 05 Oct '08

05 Oct '08

Thanks! One down, ?? to go.. Chuck Bacon -- crtb(a)cape.com ABHOR SECRECY -- DEFEND PRIVACY On Sun, 5 Oct 2008 beginners-request(a)lists.squeakfoundation.org wrote: > Hello Chuck, > > > CB> 3.8-9 is the only binary available for FreeBSD, and I could find no > CB> sources from which to build a new binary, nor for an AMD64 FreeBSD. > CB> Any hope? I find no non-binary files for 3.8-9. > > any 3.x image should run with any 3.x VM > > -- > Cheers, > > Herbert

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Beginners October 2008