I need help with a library system in prolog.
I tried to define all the books in my library this way:
book(['programming in logic'],
[nm(k, clark), nm(f, mcCabe)],
['programation'],
['editorial 123']).
And I tried to do a query for all programming books this way:
?- book(Title,Autgor,Genre,Editorial),
findall( Genre, (member('programation', Genre)), [G]).
but I need to suggest books by genre, author...
I also need to do statistics, most wanted book, genre most searched, author most wanted, things like that, but I'm not sure how to define the rules to do these queries. I have searched for examples, but only find things like family tree and I don't understand. If you could collaborate with examples for this exercise, I would appreciate too much.
For sure, modelling a library system could be a very complex topic.
I would suggest to start to learn RDF, for instance with SWI-Prolog, that has a very powerful library devoted to the task.
I just tried to use RDF to model objects simpler than biblio domain.
Anyway, I googled 'biblio ontology' and got some reasonable result, like bibo.
To start with, maybe you could consider some introductory material.
Related
I've been trying to create a chatbot (as an assignment) in prolog, so far I have made a database in a .pl file and I have listed a lot of possible conversations.
I know that prolog works like this for example if we have
Chatbot(good)
and we type
?-Chatbot(good).
it will respond
yes or ture.
Now I don't know how to use my database so that the program can work exactly as a chatbot for example without the need to write in appropriate syntax:
Hello (typed by the user)
Hi there, (typed by the program automatically)
My database is like this:
answer( question, [
[Yes, I am here]]).
question ([are you there?])
The prototype chatbot I'm aware of is ELIZA by Weizenbaum 1966.
Implementing it in Prolog is rather easy, as shown in The Art of Prolog by Sterling & Shapiro.
Googling for 'ELIZA Prolog', the first link gives you a fairly complex implementation, and you could adapt/reuse the engine with your database. But this way you will lose all the fun. I suggest you read the book and take the time to implement your own.
edit
Just in case you haven't still seen it, SWISH offers a clean, barebone ELIZA implementation among its examples.
I want to make a basic library management system in prolog. The program should answer queries like which book is issued by which student and which date book will be returned. I want guidance in terms what exact components i need to learn for it (as I am very much new to prolog), i wanna develop it rapidly as i dun have time to learn the whole thing. I will be using visual prolog 7.3
Thanks in Advance
MGD
You haven't given us much of an idea what your programming background is, so I've interpolated a couple of comments below to suggest what existing experience might help in doing parts of the Visual-Prolog application asked about.
With Visual-Prolog you have to begin with user-interface design, something that I frankly found discouraging for playing around with the Prolog coding. Think of the "window" elements you want: perhaps an input field to input a user name and another input field to enter a book title, with some buttons for "search" as your "program should answer queries" spec suggests. The output will contain information about whether a book is checked out, when it is due, etc.
Then the functional part of your design can begin. Visual-Prolog asks you to declare certain things: domains (equivalent to datatypes in other languages) and predicates (the names relations and the domains to which their various arguments apply, roughly the equivalent to routines in other languages).
Your library application sounds like it is similar to a database, a "knowledge-base" containing information about users, books, and the relationship between them (e.g. this user has this book checked out), possibly with some history (who checked out a book when, and when was it returned).
Since you want to "develop it rapidly", you will probably want to start with a very simple set of domains and predicates. Perhaps "user" and "book" are the basic domains to start with, and checkOut/2 the basic predicate (indicating the fact that a particular user currently has the particular book). Then you will probably need to add (at least) the feature of storing the book's return date. This kind of design will be easier if you've done some relational database development before.
Connecting the user-interface (UI) to the "knowledge-base" of library users & books is a matter of writing predicates that serve as event-handlers for the visual elements of the UI. This is somewhat easier if you are familiar with Visual Basic. In any case you can "stub out" the event handlers while you are building the "look and feel" part of the UI, replacing them with substantive implementations as your design moves into developing the "knowledge-base".
I m in process of understanding and building a static code analysis tool for a proprietary language from a big company. Reason for doing this , I have to review a rather large code base , and a static code analysis would help a lot and they do not have one for the language so far.
I would like to know how does one go about building a static code analysis tool , for e.g. Lint or SpLint for C.
Any books, articles , blogs , sites..etc would help.
Thanks.
I know this is an old post, but the answers don't really seem that satisfactory. This article is a pretty good introduction to the technology behind the static analysis tools, and has several links to examples.
A good book is "Secure Programming with Static Analysis" by Brian Chest and Jacob West.
You need good infrastructrure, such as a parser, a tree builder, tree analyzers, symbol table builders, flow analyzers, and then to get on with your specific task you need to code specific checks for the specific problems of interest to you, using all the infrastructure machinery.
Building all that foundation machinery is actually pretty hard, and it doesn't help you do your specific task. People don't write the operating system for every application they code; why should you build all the infrastructure? Like an OS, it is better if you simply acquire good infrastructure.
People will tell you to lex and yacc. That's kind of like suggesting you use the real time keneral part of the OS; useful, but far from all the infrastructure you really need.
Our DMS Software Reengineering Toolkit provides all the necessary infracture. It has been used to define many language front ends as well as
many tools for such languages.
Such infrastructure would allow you to define your specific nonstandard language relatively quickly, and then get on with your task of coding your special checks.
There is a blog by DeepSource that covers everything one needs to know to build an understanding of static code analysis and equip you with the basic theory and the right tools so that you can write analyzers on your own.
Here’s the link: https://deepsource.io/blog/introduction-static-code-analysis/
Obviously you need a parser for the language. A good high level AST is useful.
You need to enumerate a set of "mistakes" in the language. Without knowing more about the language in question, we can't help here. Examples: unallocated pointers in C, etc.
Combine the AST with the mistakes in #2.
I'm running a refactoring code dojo for some coworkers who asked how refactoring and patterns go together, and I need a sample code base. Anyone know of a good starting point that isn't to horrible they can't make heads or tails of the code, but can rewrite their way to something useful?
I would actually suggesting refactoring some of your and your coworkers' code.
There are always places that an existing codebase can be refactored, and the familiarity with the existing code will help make it feel more like a useful thing and less like an exercise. Find something in your company's code to use as an example, if possible.
Here are some codes, both the original and the refactored version, so you can prepare your kata or simply compare the results once the refactoring is performed:
My books have both shorter examples and a longer, actually a book long example. Code is free to download.
VB Code Examples
C# Code Examples
A nice example from Refactoring Workbook
There are a lot of examples on the internet of simple games like Tic-Tac-Toe or Snake that have a lot of smells but are simple enough to start with refactoring.
The first chapter in Martin Fowler "Refactoring" is a good starting point to refactoring. I understood most of the concepts when one of my teachers at school used this example.
What is the general knowledge level of your coworkers?
Something basic as code duplication should be easy to wrap their heads around. Two pieces of (nearly) identical code that can be refactored into a reusable method, class, whatever. Using a (past) example from your own codebase would be good.
I would recommend you to develop a simple example project for a specific requirement.
Then you add one more requirement and make changes to the existing classes . You keep on doing this and show them how you are finding it difficult to make each change when the code is not designed properly. This will make them realize easily because, this is what those ppl will be doing in their day to day work. Make them realize that , if patterns and principles are not followed from beginning, how are they going to end up in mess at the end.
When they realize that,then you start from scratch or refactor the existing messed up code .Now add a requirement and make them realize that it is easy to make a change in the refactored code, so that you need to test only a few classes. One change would not affect others and so on.
You could use the computer ,keyboard and printer class as an example. Add requirements like, you will be wanting the computer to read from mouse , then one more requirement can be like your computer would want to save it in hard disk than printing. Finally your refactored code should be like, your computer class should depend on abstract input device class and output device class. And your keyboard class should inherit from Inputdevice class.
Clean Code: A Handbook of Agile Software Craftsmanship by Robert C. Martin considers refactoring.
I'm loving Refactoring Guru examples.
In there you can find design patterns examples too.
Refactoring is non-functional requirement when code perform correct functionality for which it is designed however difficult to debug, requires more effort to maintain and some performance bottleneck. Refactoring is to change to be easily maintainable, good readability and improve efficiency.
Thus we need to focus on criteria to make code more readable, easy to maintain.
Its obvious that having very large method/function might be difficult to understand.
Class depends on other hundreds of class make thing worst while debugging.
Code should be readable just like reading some workflow.
You can also use tools like sonar which can help you to identify critical criteria such as "Cyclomatic Complexity"
http://www.sonarsource.org/managing-cyclomatic-complexity-to-increase-maintainability/
You ask them to write code them self and check how tool does refactoring.
Apart from that, you can write code in eclipse and there is option available which does refactoring for you...
It's a bit dated (2003), but IBM has several refactoring examples (that work[ed?] in Eclipse) at http://www.ibm.com/developerworks/library/os-ecref/
I am developing my first ASP.NET MVC application using the Entity Framework. I have no previous .NET experience, although I'm fluent in other OO languages. I am having trouble understanding Linq to Entity query expressions, more specifically its syntax and how to render the results on an ASP page.
For example, I am joining three tables (entities) together and trying to iterate over the results, but I get all sorts of type errors. Every example I find on Google, SO, or MSFT hasn't been straightforward and each site takes their own approach. I looked at the book Programming Entity Framework, but this too seems to be over my head at the moment.
I am looking for clear, concise examples of executing the equivalent of complex multiple joins and iterating over the results.
Thanks
I've just started this myself, and I bought both the wrox book and the o'reilly one.
I've found the wrox one a little more inaccessible - the language used in it is a bit heavier, and the layout/organisation isn't quite so 'flowy' (is that a word? hehe).
The o'reilly one on the other hand is a cracking read, and really does lead you nicely through it. It's available on safaribooks too if you have a sub, I got it from Amazon who seemed one of the few places to have it in stock. Very much recommended.
take a look at these samples - http://blogs.msdn.com/adonet/archive/2007/03/13/101-linq-samples-updated.aspx
i picked up the concept from these examples itself
Scott Guthrie's blog has also really good explanation & samples
Sounds to me like you should get yourself a good book on the subject. Since you have no previous experience in .NET a general book that covers LINQ might be a start and then a ASP.NET-MVC specific one.
Perhaps the reason why being fluent in "other" OO languages isn't helping is that LINQ isn't an OO language, its much more functional and therefore takes a different way of reasoning to understand well.