Archive for August, 2007

Last Week of Summer

Topic: Musings| No Comments »

'Tis be the last week of summer, and while the term winding down can only loosely apply to work, everything else certainly is winding down. As I write this, vast portions of my life are beginning their slow journey toward Rhode Island, vast bureaucratic machines on both coasts are coming to life and dealing with the things they need to deal with before I can leave, and I am rapidly becoming more distracted. Six days from now I shall be in one of those long metal tubes hurtling at immense speeds towards another ocean. Some day soon, I shall write more about this summer and being here, but for now, the summer's ending.

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Parser Combinators, Scala, Haskell

Topic: monads, parser combinators, scala, haskell, CS| No Comments »

Earlier today, thanks to Itay, I was introduced to the idea of parser combinators in conjunction with a discussion we were having. From what I understood (hence not misrepresenting anyone), he knew of parser combinators from Scala, where they are a part of the standard library, of course my customary Google search of new terms led me to documentation for the Haskell Parser Generator, which in itself is mildly different from the Scala equivalent, understandably so seeing how the principles behind both languages differ. I have been trying to get a better grasp of both languages for a while, and though I have been doing this for widely divergent reasons (Haskell - strong links to math, the cool factor, reading a decent paper on monads on the recommendation of a couple of people, and not knowing how to use it, Scala - lots of chatter about it coming my way from Itay, the entire actor model, a bunch of interesting documentation), I have been failing miserably, since while I know what both involve to a first approximation, not writing any large chunk of code in either implies not being used to the idiosyncrasies of either, and not being able to parse the language well in one's head (it took me a 40 minute train ride home to figure out to a first approximation what some of the code in here means). So I am going to try learning parser combinators in one of the languages (possibly Scala since it would gel with something I am doing with Itay), and then eventually convert what I learn in one into the other, and hope that works. Either ways from what little I read of parser combinators they seem like an interesting model for parsers, at least the scala implementation seems to be fairly nifty in terms of being literally readable as a grammar.

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STM, Topology

Topic: topology, stm, CS| No Comments »

This is one of two or three short posts I will be making today, and will as such probably never be seen as a result of not actually having visible text for very long. A casual glance through programming.reddit.com will show a recent surge in interest in Software Transactional Memory. Having missed most of the concurrency train (I still have to read the Erlang book), I am pretty amused by what all this concurrency means. I think the processes themselves are fairly interesting, but I claim to be entirely inept at it, I understand what STM means, what it entails, I haven't used it. However what does interest me about STM is a couple of papers written by Herlihy (there are others, I just happened to run across these while going through what Brown professors did) relating concurrency to topology. The papers are freely available on the website, and while I am still working on actually reading them, I am hoping posting here will shame me into actually completing this eventually. On the positive side, trying to parse the papers has meant having to read and understand a book on point set topology, one of the things I did in the hazy days of my sophomore year and have forgotten fairly successfully. Of course seeing as parsing math texts themselves takes a while, and paper and pen, this is slow going.

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The Many Lives of Java

Topic: CS| 2 Comments »

It is fairly well known that I don't like Java nearly enough, too much of it bothers me. I no longer walk around making claims about the superiority of other languages, time has shown me that this would be oversimplifying facts. This is not a post about my feelings on Java, I could talk about my feelings about developing in a REPL but have recently discovered that not all REPLs are the same, and some offer much more advanced editing features, even if one needs to leave the familiar confines of vi and get used to Emacs to use them effectively. Hence no REPLs for now.
However earlier today my work machine ran one of those Java update things (it is surprising how many things are attempting to update themselves these days), and it had this nice InstallShield wizard, with messages on it, and the messages seemed to have been written by someone in marketing to exalt all that Java is, in reverse chronological order. So the install started by talking about how one was now installing Java, found in everything from Blu-ray DVD Players, to cellphones, and ended with assuring the user that they were now ready to go out and face the Java Powered Internet (one does wonder what NetBSDs equivalent of these messages would be). 'twas amusing.

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Turing Machines and 7-Tuples

Topic: formalism, math, turing machine, CS| No Comments »

Edit: Now updated with link to picture

This has been bothering me since yesterday, and were it not for people in the CS department e-mailing me stuff, it would still bother me. Nothing very deep about this, but it's an interesting difference in notation.

Yesterday afternoon, EAS, my cubemate, was looking at a Facebook photograph of someone who had the 7-tuple formal representation for a Turing machine tattooed on their body. That's OK, people tend to have interesting tattoos. What threw me off about this picture however was the fact that the tuple looked different from what my memory was serving up, and this is bad since one does hope that nearly a semester's worth of sitting in on classes, and a semester's worth of TAing a course would at least leave me with a not so wrong memory of what these tuples are, even though admittedly they don't show up all that often on assignments or such.

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