Re: [TYPES] The type/object distinction and possible synthesis of OOP and imperative programming languages
I don't quite think I understand what you are saying. Are you saying that mathematical models are not a good foundation for computer science because computers are really made out of electronic gates? All I need to do is show that my model reduces to some basic physical implementation (with perhaps some allowances for infinity) and then I can promptly forget about that messy business and proceed to use my clean mathematical model. The reason any model of computation exists is that it is easier to think about a problem in some terms than in others. By showing how to transform one model to another you make it possible to choose exactly how you wish to solve a problem. The reason we do not work directly in what are called von Neumann machines is that they are not convenient for all kinds of problems. However we can build a compiler to translate anything to anything else so we I don't see why anybody would care. On Thu, Apr 18, 2013 at 5:53 PM, Mark Janssen dreamingforw...@gmail.comwrote: [ The Types Forum, http://lists.seas.upenn.edu/mailman/listinfo/types-list] On Mon, Apr 15, 2013 at 2:53 AM, Moez AbdelGawad moeza...@outlook.com wrote: I'm not quite sure I understand your question, but I'll give it a shot. :-) I'm in this same camp too :) I am very thankful for the references given by everyone. Unfortunately my library does not have the titles and it will be some time before I can acquire them. I hope it not too intrusive to offer a few points that I've garnered from this conversation until I can study the history further. The main thing that I notice is that there is a heavy bias in academia towards mathematical models. I understand that Turing Machines, for example, were originally abstract computational concepts before there was an implementation in hardware, so I have some sympathies with that view, yet, should not the Science of Computer Science concern itself with how to map these abstract computational concepts into actual computational hardware? Otherwise, why not keep the field within mathematics and philosophy (where Logic traditionally has been)? I find it remarkable, for example, that the simple continued application of And/Or/Not gates can perform all the computation that C.S. concerns itself with and these form the basis for computer science in my mind, along with Boolean logic. (The implementation of digital logic into physical hardware is where C.S. stops and Engineering begins, I would argue.) But still, it seems that there are two ends, two poles, to the whole computer science enterprise that haven't been sufficiently *separated* so that they can be appreciated: logic gates vs. logical calculus and symbols. There is very little crossover as I can see. Perhaps the problem is the common use of the Greek root logikos; in the former, it pertains to binary arithmetic, where in the latter, it retains it's original Greek pertaining to *speech* and symbols, logos). Further, one can notice that in the former, the progression has been towards more sophisticated Data Structures (hence the evolution towards Object-Orientation), where in the latter (I'm guessing, since it's not my area of expertise) the progression has been towards function sophistication (where recursion seems to be paramount). In any case, I look forward to diving into the books and references you've all offered so generously so that I can appreciate the field and its history better. Mark Janssen Pacific Lutheran University Tacoma, Washington -- http://mail.python.org/mailman/listinfo/python-list
Re: [TYPES] The type/object distinction and possible synthesis of OOP and imperative programming languages
Warning, this is a bit of a rant. That paragraph from Wikipedia seems to be confused. It gives the fourth paradigm as declarative but then says first order logic for logic programming. It seems somebody did an incomplete replacement of declarative for logic. Wikipedia is often schizophrenic like that. Personally, I think that object oriented and logical programming only became official paradigms because there was a certain level of hype for them in the 1980s and nobody has thought to strike them off the list after the hype died down. Object-oriented, as constituted today, is just a layer of abstraction over imperative programming (or imperative style programming in functional languages, because objects require side-effects). What object-oriented language actually in use now isn't just an imperative language with fancy abstraction mechanisms? The problem with having declarative languages as a paradigm (which logical languages would be a part) is that it feels like it should be a miscellaneous category. Being declarative doesn't tell you much except that some machine is going to turn your descriptions of something into some kind of action. In logical programming it is a set of predicates, but it could just as easily be almost anything else. In a way all languages are declarative, it is just that we have some standard interpretations of what is declared that are very common (imperative and functional). My wish is that the idea of there being four paradigms would be abandoned the same we the idea of four food groups has been abandoned (which may surprise some of you). We have more than four different modes of thinking when programming and some are much more important than others and some are subsets of others. We should teach students a more sophisticated view. Ironically Wikipedia also shows us this complexity. The programming language paradigm side bar actually reveals the wealth of different styles that are available. There is simply no clean and useful way to overlay the four paradigms over what we see there, so it should be abandoned because it gives students a false idea. On Wed, Apr 17, 2013 at 9:42 AM, Andreas Abel andreas.a...@ifi.lmu.dewrote: [ The Types Forum, http://lists.seas.upenn.edu/** mailman/listinfo/types-listhttp://lists.seas.upenn.edu/mailman/listinfo/types-list] On 17.04.2013 11:30, Uday S Reddy wrote: Mark Janssen writes: From: en.wikipedia.org: Programming_paradigm: A programming paradigm is a fundamental style of computer programming. There are four main paradigms: object-oriented, imperative, functional and declarative. Their foundations are distinct models of computation: Turing machine for object-oriented and imperative programming, lambda calculus for functional programming, and first order logic for logic programming. I removed the second sentence relating paradigms to computation models and put it on the talk page instead. It does not make sense to connect imperative programming to Turing machines like functional programming to lambda calculus. A better match would be random access machines, but the whole idea of a connection between a programming paradigm and a computation model is misleading. While I understand the interest in purely theoretical models, I wonder two things: 1) Are these distinct models of computation valid? And, 2) If so, shouldn't a theory of types announce what model of computation they are working from? These distinctions are not fully valid. - Functional programming, logic programming and imperative programming are three different *computational mechanisms*. - Object-orientation and abstract data types are two different ways of building higher-level *abstractions*. The authors of this paragraph did not understand that computational mechanisms and higher-level abstractions are separate, orthogonal dimensions in programming language design. All six combinations, obtained by picking a computational mechanism from the first bullet and an abstraction mechanism from the second bullet, are possible. It is a mistake to put object-orientation in the first bullet. Their idea of paradigm is vague and ill-defined. Cheers, Uday Reddy -- Andreas AbelDu bist der geliebte Mensch. Theoretical Computer Science, University of Munich Oettingenstr. 67, D-80538 Munich, GERMANY andreas.a...@ifi.lmu.de http://www2.tcs.ifi.lmu.de/~**abel/ http://www2.tcs.ifi.lmu.de/~abel/ -- http://mail.python.org/mailman/listinfo/python-list
