August 2009 - Pharo-dev - lists.pharo.org

[Pharo-project] New Pharo based on core 10413
by Damien Cassou Aug. 16, 2009

Aug. 16, 2009

Please download and report problems: http://pharo-project.org/pharo-download -- Damien Cassou http://damiencassou.seasidehosting.st "Lambdas are relegated to relative obscurity until Java makes them popular by not having them." James Iry

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[Pharo-project] Mouse does not find matching when closing paren is immediately following single quotes
by csrabak＠bol.com.br Aug. 16, 2009

Aug. 16, 2009

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[Pharo-project] Newbie new initialize [WAS: Incompatibilities was: #< if at first you dont succeed..]
by Ken.Dickey Aug. 16, 2009

Aug. 16, 2009

I highly recommend _Squeak by Example_. My recollection (highly suspect) is that they refer to the base change which added #initialize. http://squeakbyexample.org/ Good on you, -KenD

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[Pharo-project] Monitoring Transcript progress from UI Process
by Chris Muller Aug. 15, 2009

Aug. 15, 2009

Greetings, I am a Pharo newbie. What a nice image! One of the things I'd like to do is monitor the Magma test-suite while it runs; Magma intercepts Notifications from its test suite code to simply Transcript show: them by default. But the Transcript doesn't render them while the UI process is busy, as the following demonstrates: "Screen doesn't update until entire script is complete.." World findATranscript: nil. 1 to: 100 do: [ : n | Transcript cr; show: n; endEntry ] I also tried a World doOneCycleNow but it blows up.. Doesn't seem right anyway.. Thanks, Chris

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[Pharo-project] #< if at first you dont succeed..
by Ken.Dickey Aug. 15, 2009

Aug. 15, 2009

Igor Stasenko <siguctua(a)gmail.com> > By reading a comment: Â "Not defined on Complex numbers" > i wonder why implementation is different than following: ... How about this wording: "Mathematically, complex numbers are a superset of the real numbers. Complex numbers with a zero imaginary part ARE real numbers and should behave as such. That the #< selector is part of the Complex class is an artifact of the current implementation. There is no agreed upon model for < comparison for complex numbers in general." Better? -KenD

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[Pharo-project] #< if at first you dont succeed..
by Ken.Dickey Aug. 15, 2009

Aug. 15, 2009

> i disagree. > As i said earlier, a square root function result is not defined for > arguments less than zero in real (R) set. Right, only for complex (C). R < C [C contains R]. > This is strictly mathematical behavior, same as division does not > defines a value for zero. My _Elementary Functions_ book has a nice section which defines the square root of -1 to be 1i. I pick up _Handbook of Physical Calculations_ and find an entire section on the mathematics of alternating current which uses complex math exclusively. I see why, given Smalltalk's history, one does not wish to change the way things are done. This is a bit different from implying complex mathematics is not mathematics. > Just think about, how many code i could break, if i return an Infinity > (or something like this) as a result of division by zero instead > of signaling error. My recollection (again, not to be trusted) is that Java returns an IEEE infinity rather than throwing an exception. I do not recommend this either, which is why I am puzzled by #ln returning a NaN. Again, my recommendation is that the current Complex implementation be removed from Pharo-Core. Reluctant as I am to suggest it, an allowComplexResults global preference could be used, with the usual "Here Be Dragons" warnings. Such a preference would clearly state that it is to allow functions like #ln and #sqrt to return complex results and would only be settable if a Complex number package was loaded. Cheers, -KenD PS: My apologies, but my laptop died and I am borrowing time on someone else's computer. I intent to browse "sqrt senders" when I get another machine to see what code is breaking.

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Re: [Pharo-project] #< if at first you dont succeed..
by Ken.Dickey Aug. 15, 2009

Aug. 15, 2009

Taking a hint from the comments (yes, I do listen), here is a "less complex" :) solution: Complex>> < aNumber "Not defined on Complex numbers" ^self asReal < aNumber asReal Complex>> asReal "Answer real-part of self if imaginary is zero else, error" (imaginary = 0) ifTrue: [^real] ifFalse: [self error: 'Can''t convert to real'] Better? -KenD

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[Pharo-project] [ANN] Fundamentals volume 1
by Andres Valloud Aug. 15, 2009

Aug. 15, 2009

Hello, I just published the 400 page book Fundamentals of Smalltalk Programming Technique, volume 1. To some extent it's fitting that I am publishing another book this time of the year. I started writing the Mentoring Course book (of which the Hash book was chapter 7) almost 4 years ago. The three books total about 1200 pages. Something I realized with the Mentoring Course book is that I could take advantage of mentoring myself because I had already sharpened several Smalltalk skills. The Fundamentals book talks about these abilities. As with the Mentoring Course book, there is too much material for a single book. Thus, the first volume just published talks about the controlled manipulation of boolean expressions, inheritance, and polymorphism. In fact, there is a continuum of points of view on the subjects, ranging from the goal of producing very little yet highly maintainable code, to the architecture of highly optimized implementations, as well as valuable compromises in between. In fact, at times, it is possible to avoid sacrificing flexibility for speed, or viceversa. The second volume will talk about enumeration, recursion, weakness, and optimization. I am sure it will be a fun book to write. In the mean time, enjoy volume 1! http://www.lulu.com/content/7451511 http://www.lulu.com/avSmalltalkBooks Andres.

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Re: [Pharo-project] #< if at first you dont succeed..
by kend Aug. 15, 2009

Aug. 15, 2009

Schwab,Wilhelm K > You seem determined to have the behavior of Float change when the complex > package is installed, and there are various objections to that from > multiple people; those objections are well founded. My interpretation of the responses I have received is "Change breaks History, we have a strong history" not "these suggestions are worse approximations to mathematics". I accept the first reasoning for Squeak. Squeak supports history (backward compatible) at the expense of, e.g., ANSI Smalltalk closures. Pharo has a slightly different goal set and speaks of "reinventing Smalltalk". I believe the changes I suggested better approximate mathematics and logic. I would prefer to see arguments that I am doing bad math, not that "doing better math is a change that we don't want". Once again, the discussion here implies that the Complex class should be removed from Pharo-Core into its own Package. ====== BTW, I fail too see the logic that (-4 sqrt) raises an exception but that (-3 ln) answers a NaN. I would expect both cases to raise exceptions. Any hints on why this is the case? Perhaps both cases should raise and exception with the option to load a/the Complex package? ====== Thanks again for your thoughtful consideration and input, -KenD

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[Pharo-project] Question about Socket
by Mariano Martinez Peck Aug. 15, 2009

Aug. 15, 2009

Hi folks: I am preparing my SqueakDBX talk for ESUG and I am doing some comparisons between a database driver with an external library trough FFI and a native driver. I know FFI locks the VM until the function it is being invoked, finishes. But I don't know what happens with Sockets. Do sockets lock the hole VM until you obtain a response? Thanks for any light in this field. Best, Mariano

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