Beginners May 2020

beginners@lists.squeakfoundation.org

4 participants
4 discussions

Odd behavior in inject:into: on simple change in Boolean test sequence
by tty 31 May '20

31 May '20

Hi folks. I have a bit of code I am attempting to expand and I am getting strange behavior on a very simple change in structure. I am parsing '2 * 3 / 2" and returning the product of the terms. Works fine. Here is the original code. it works as intended. * result := pairs inject: first into: [ :total :pair | |p| p := pair reject:[:a | a class = OrderedCollection]. (p first = '*') ifTrue: [total := (total * p last )] ifFalse: [ (p last = 0) ifTrue:[^NaNError]. "prevent divide by 0" total := ( total / p last )] ] .* However, If I make a very simple change to the internal logic by changing the ifTrue: ifFalse: to two separate tests 'total' goes nil on the second pass. * result := pairs inject: first into: [ :total :pair | |p| p := pair reject:[:a | a class = OrderedCollection]. (p first = '*') ifTrue: [total := (total * p last )] . (p first = '/') ifTrue: [ (p last = 0) ifTrue:[^NaNError]. "prevent divide by 0" total := ( total / p last )] ] .* it blows up on the second pass as 'total' is Nil and the division throughs a DNU. yet, |p| is populated with #('/' 2) Thanks in advance -- Sent from: http://forum.world.st/Squeak-Beginners-f107673.html

1 0

Repost from twitter : running 1983 Smalltalk. Today
by Davide Grandi 27 May '20

27 May '20

From Torsten Bergman - @TorstenAstares https://twitter.com/TorstenAstares/status/1264820045840027649 "Dan Banay just released a few days ago, on the day of the 80th anniversary of Alan Kay, a fully functional Smalltalk-80 VM capable of running the original ST-80 images as distributed by Xerox Parc in 1979 and 1980" https://github.com/dbanay/Smalltalk very very intriguing. -- Ing. Davide Grandi linkedin : http://linkedin.com/in/davidegrandi

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Float readFrom:'1e0.5' does not equal 1 * (10 raisedTo:0.5)
by tty 25 May '20

25 May '20

Float readFrom:'1e0.5' print it ->1.0 1 * (10 raisedTo:0.5) print it -> 3.1622776601683795 What am I missing here? thank you for your time. -- Sent from: http://forum.world.st/Squeak-Beginners-f107673.html

1 1

Reading a .bz2 file with XML tools
by tty 14 May '20

14 May '20

Hi all. In Java land, they can wrap readers ...roughly speaking an XMLReaderWriter wraps a BZ2ReaderWriter and the XML tools can read/write to the .bz2 file just like a regular file. Is there a similar mechanism in Squeak? thank you for your time -- Sent from: http://forum.world.st/Squeak-Beginners-f107673.html

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Beginners May 2020