How to make a C-Like Interpreted Scripting Language in C# - c#

Question:
I am looking to develop a Scripting Language like Lua, but you use
if (paramters) {
codeToDo()
}
rather than
if parameters do
code_to_do()
end
but have yet to find a good tutorial out their on the internet.
Parameters:
I want it to be interpreted, and I also want to make it in C#, so that it integrates with it the easiest.

Writing a language and an interpreter is not an easy task, you have to define the complete syntax and after write a parser for it, finally you have to implement a interpreter capable of executing your language.
There are already answers about creating programming languages here on SO:
Suggestions for writing a programming language?
How would you go about writing a simple programming language?
Some books that could guide you in the right direction:
Language Implementation Patterns
" Written by Terrence Parr creator of ANTLR a parse generation tool in Java, teaches the basics of language definition and the implementation of a bytecode vm."
Writing Compilers and Interpreters: A Software Engineering Approach
Couldnt find a practical book with code in C#, most of books about compilers comes with code in C, only some with Java.

Related

Android to WP7 absolute newbie question: C# or VB?

I'm going to migrate my Android application into WP7 platform. Android one contains heavy enough calculation stuff (encryption/decryption), plus extensive usage of DB (SQLite) and some graphics (simple) and I'm trying to figure which language to select: either C# or VB
I have some experience both in C# and VB.net, but can't decide which one to select, any clues?
I would recommend C#, based on a couple of factors:
I assume the Android application is written in Java. Between C# and VB, C# is the most similar.
If you are doing lots of calculations, C#'s more terse syntax will probably make the code easier to read. VB is more verbose and thus tends to produce more clutter.
Since you are new to the platform, you will definitely find a lot more resources with C# code examples than with VB.
I went from VB.net to C# and wouldn't ever go back through my own choice!
Aside from the technical differences (see here for just one comparison), it's my personal opinion that C# is more readable, fluent and just plain better.
Do a search on google for heaps of comparisons on why one is better than the other. At the end of the day it's your personal preference... try both and see which you prefer.
There are no technical benefits or drawbacks to choosing either language; the complete set of APIs and platform features are available to you whether you choose C# or VB.NET, so it comes down to whichever you are most comfortable with or want to spend more time with.
The only thing that might sway it one way or another is that (in my opinion) there are more samples, blog posts, and general help written in C# than VB.NET, but that's about the only differentiator I can think of.
If you aren't particularly familiar with either then definitely use C#. By far and way the vast majority of code you will come across in the Web and in books on Silverlight will be written C#.
I'd go with C#, it's a far more popular language. Furthermore, Java to C# is an easier transition.
Edit:
Popularity of a language make's it easier to find information and perhaps more importantly, quality developers.
Choose the language you are more comfortable with.
I would suggest c# because it's more similar to java. So maybe you will manage to save code structure.
C# for sure. C# is a lot more alike Java, and syntax alike much more compatible.
Next to that C# is more popular so more resources for it, and because of the extra time they spend on C# the compiler slightly generates higher performance MSIL.
If you know Java you'll find C# very comfortable to transition to and work with, especially if you're having to maintain older Java code as well as working on the new project. I've worked in situations where I had to work with VB6, VB.NET and C# code within the course of a day and it can be tricky to remember not to use or to use semi-colons or that the variable type goes first or last.

How Similar are Java, C#, and Python? [closed]

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I know it is a kind of broad question but any answer are appreciated.
All:
Require some form of runtime on your system (JVM/.net/Python runtime)
All can probably be compiled to executables without the runtime (this is iffy and situational, none of them are designed to work this way)
Are good languages
All have specific areas where they are much more appropriate than the other two
Java:
Tries very hard to be Cross Platform--generally succeeds
Little access to platform features that are not in the SDK
Slowest of the three to change and does not contain features common to the other two such as closures
Very backwards compatible (partly because of the previous point)
FAST (about 2x slower than C, quite a few x faster than python)
Probably has the most library support of the three
Strong multi-platform server systems already deployed using J2EE
Scales down to embedded (I've worked on 2 different embedded java projects--coming soon to a cable box near you)
Static
C#
Quicker to add new features
Windows only--Mono is cross platform but does not have the library support.
Started very similar to Java but has many more language features now.
Much better access to windows APIs
Not sure about speed--I think it's similar to Java.
Very good library support
The only one of the three that you have to pay for (it's free for "entry level")
Static
Python
Language is cross platform. Not sure about non-language platform access (such as drag-and-drop)--anyone know?
Probably an easier language to learn
The only one of the three that does not use c-like syntax
Slowest of the three, but still pretty darn fast compared to other dynamic languages.
Dynamic
This link is also interesting
Python is a dynamic language where Java and C# are really not. It is totally different than the other two. There are ways to accomplishing things in Python that do not translate well to the others and vice versa.
Java and C# look the same, but they have differences between the two under the sheets. Being an expert in one, does not make you an expert in the other by any stretch of the imagination. The syntax is similar and libraries are too, so it would be easier to get up to speed in one or the other, but there are subtleties that can trip you up.
C# and Java have almost identical syntax and very similar libraries. There are differences that you have to be aware of (Type Erasure in Java, for example).
Python is a completely different animal. It is a dynamic language (where the other two aren't). Python winds up being closer in style to something like Ruby.
Java and C# are statically typed languages, while Python is a dynamically typed language. That's a huge difference.
The syntax of Java and C# is similar (but I would not call it "almost identical" as Justin Niessner says).
Java and c# are pretty similar in terms of syntax and are mostly strongly typed (C# is getting more dynamic with every version), Python is a dynamic language
Java and C# are very similar and are syntactically similar to C/C++. They also use braces to mark code blocks.
Python is completely different. Although imperative like Java and C#, Python uses indentation to define blocks of code.
Java and C# are also compiled languages, whereas Python is interpreted and dynamic.
Python, Ruby, and Groovy are somewhat similar languages.
C# and Java are easy to move between, although I don't know many people who are experts in both. C#'s syntax is based off of Java, so they read very, very similarly. They both run cross-platform; Java on the JVM, C# on .NET or Mono. They're both OOP, and widely used for web development. I'd use whichever the team was more familiar with.
Python's off to the side there. It's also used frequently as a scripting language. It can use classes and object orientation, but isn't forced to. It's not as well supported for web work. I'd use this for a different set of tasks than C#/Java.
C# and Java are the two languages you listed that are most similar. Python has a very different syntax, and uses a slightly different programming model. Both C# and Java are Object Oriented languages at their core, with increasing nods to Dynamic Typing. Python began as a Dynamically Typed scripting language and has been picking up more and more Object Oriented features over the years.
The C# class library (.NET Framework) is theoretically multi-platform, though it's heavily weighted towards the Windows platform, and any other OS compatibility is largely an afterthought. The .NET framework currently has two "official" frameworks for building windowed applications (Windows Forms, and WPF) and two "official" frameworks for building web applications (ASP.NET, and ASP.NET MVC). Windows Forms is similar to Java Swing, but the other four frameworks are very different from much of what is found in the Java or Python worlds. There are many language features in C# that are different or lacking in Java, such as Delegates.
The Java class library is pretty solidly multi-platform. It's officially supported desktop and web frameworks (Swing and J2EE) are generally regarded as slow, and difficult to use. However, there is a very lively open source community which has built several competing frameworks that are very powerful and versatile. Java as a language is very slow to introduce new language features, though it is runtime-compatible with several other languages that run on the Java platform (Groovy, Jython, Scala, etc..). Java is the language which has has the most run-time optimizations put into it, so an application written in Java is almost certainly going to be faster than an application written in C# or Python.
Python is an interpreted language (in general), and is pretty solidly multi-platform. Python has no "official" desktop or web frameworks, though desktop applications can be written using GTK or Qt support, both of which are multi-platform. Django has become a de-facto standard for Python web development, and is regarded as a very powerful and expressive framework. Python is at this point fully Object Oriented, and is notable for it's powerful tools for working with collections/arrays/lists. As an interpreted language, Python will be significantly slower than either C# or Java.
Python was made to be simpler, more readable, flexible and object oriented than what existed before - i.e. Java, Perl etc. It's actually closer to Java than it is to Ruby. Ruby is more like Smalltalk. Think of Python as Java without the stuff that mostly gets in your way, makes things awkward to do, slows you down or clutters the essence of your logic. So no semi-colons, curly braces for scoping. No static variable declaration or variables at all really they're identifiers that point to objects instead.
There's also a standard style guide for Python unlike other languages. Indentation is used to indicate scope and inconsistent indentation is a syntax error.
It also includes some often used things built into the language: lists, dictionaries, sets, generators etc.
Java is nice for those familiar with C / C++ syntax and are set in their ways, like that syntax and find it readable. Ruby and Python are for those that preferred Pascal or Smalltalk to C, like Lisp etc.
They are not similar at ALL. They all take widely different approaches to OOP, syntax, and static/dynamic typing.

F# vs Haskell vs Lisp - which language to learn? [closed]

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I've heard a lot about functional programming languages and I'm willing to learn one. I guess it will be mostly for fun, however, I hope it will improve my programming skills.
I have mostly C#/.NET background, so my first choice is to learn F# (because of .NET and familiarity with Visual Studio). On the on other hand, I wonder if F# has features like Lisp macros or Haskell higher order functions.
Could you compare F#, Haskell and Lisp? Which one will be the language of your choice?
F# is my language of choice, but I'd strongly recommend learning them all. They are all quite different and interesting in their own right. Here's a quick over view to each one (with perhaps a slight F# bias), you can easily find more info by googling:
F# - is a language that makes it easy to program in the functional style, lets you easily copy objects rather than mutating them. It also gives you interesting data types, like tuples and algebraic data types, useful language constructs such as pattern matching and list comprehensions. It also has OO and imperative features and good access to libraries, since you can use any .NET framework component.
Haskell - is a pure and lazy functional language, making a rare or even unique beast. This means there are no side effects at all, unless they are tracked by a monad. Haskel too has tuples, algebraic data and pattern matching.
Lisp - whereas F# and Haskell are statically typed, lisp is dynamically typed. It has distinctive syntax which uses lots of parentheses and provides an interesting macro feature that allows you to make transformations to the program itself and extend the syntax.
I had the same question once
Since then, I have done some programming in F#. Now I am very glad I did, since it is realy helpful to understand LINQ in C# and that happened to be my background too. (I almost never use foreach in C# now since I learned F#)
I learned through F# a lot of things about lazy evalution, lists and sequences, all of which you could pick any language for with good support for lists, tuples, and so on (like any functional language I guess), but if you pick F#, all of this will be very useful in C# too. Maybe you already know all of this stuff and use it right, but in case you don't, pick F#.
I started out here : a very nice video tutorial, very impressive and a very inspiring tutor.
Currently I'm watching these video's on Channel 9 on the basics of Functional programming. It's explained using Haskell, but the basics apply to all languages. I must say it's very informative and easy to understand.
This is a very subjective question.
My opinion is that Scheme (a Lisp variant) and reading SICP is the right thing. You will learn a lot.
But for practical purposes and if you are a .NET developer then maybe F# is better.
I don't know F# but I like to play with it sometimes. My language is Clojure which is very functional and works on the CLR too, but the JVM version is the main version.
It overs you a lot of the stuff you want. The main diffrence to F# is that Clojure is dynamicly typed and it has really good way handle concurency (one of the best I would say).
BTW.
Did you know that F# was made because Haskell was to hard to get running on the CLR? (Thats not the whole story of course but its part of it)
Nobody actually answered this specific question: "I wonder if F# has features like Lisp macros or Haskell higher order functions."
F# does not offer macros. Also, it does not offer higher-kinded types (which is what I thought you were asking at first).
F# does offer higher-order functions in that you can easily write a function that takes a function and returns a function. In fact, C# (or really any .NET language) can do this as the Func delegate is part of the .NET framework.
Why choose?
Learn both Lisp and Haskell on your own.
No point in learning F# on your own time though. If you need it for work, you'll learn it at work ;)
EDIT: The guy was looking at language to learn for fun. Well, Lisp and Haskell are good candidates since fun is all they are going to be used for (no paid jobs there). He "might" (although unlikely) have opportunity to use F# at work (he is in MS shop), so why learning something in free time when he can be paid learning it at work.
I learned all of them to a diffeent degree, and would advise starting with Scheme (a Lisp dialect) - simply because it is easiest to learn. Haskell and F# are statically typed, which is a big advantage for real-life projects, but IMHO they have a little "too much" syntax and are not as easy to pick up as Scheme.
There is a nice Scheme implementation for .NET - IronScheme. You can take a look at my article "Playing with IronScheme" to see if you like it.
If We compare this three languages I'll recommend Haskell. It is more practical than LISP I think (because it's type system) and more powerful and clever than F#. As far as you know F# is a .NET port of OCaml and to some extent it is not ideoligally clear as Haskell is or as OCaml is. I'll recommend you study Haskell or OCaml to know how inconvinient F# is.

C++ or Python for C# programmer? [closed]

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I am a corporate C# programmer. I found some time to invest into myself and stumbed upon a dilemma. Where to go from now? C#/.NET is easy to learn, develop for, etc. In future I would want to apply to Microsoft or Google, and want to invest spare time wisely, so what I will learn will flourish in future.
So: Python or C++ for a C# programmer? I am a little scared of C++ because developing anything in it takes ages. Python is easy, but I take it as a child-play language, which still need lots of patching to be some mature development tool/language.
Any C# developers having same dilemma?
I Am a little scared of C++ because developing anything in it takes ages.
I'm not sure how you can say that when you say yourself that you have no experience in the language. C++ is a good tool for some things, Python is good for other things. What you want to do should be driving this decision, not the technology in and of itself.
C# programmer or not, I would assume that you can pick up any language, but a language is just a tool, so your question is difficult to answer.
Python may be easier to get started with, but a dynamically typed scripting language is a very different language from C# or C++. You will learn more about programming learning it than you will by hopping to a close cousin of a language you already know. Really, solid familiarity with at least one scripting language (Python, Perl and Ruby are the favorites) should be a requirement for all programmers.
If you want to apply to Google then Python might be the one to go for, surely MS would like the C# already. If nothing else the competition would not be as fierce as there are much more folk out there with multi years of C++ experience. Also Python gives you a broader language skill and would be a good path to more languages and scripting.
But as said and will be said again, choose your tool wisely and see whether it's a nail or a screw you're trying to secure.
C# is a little closer to Java and C++ than it is to Python, so learn Python first out of the two.
However, my advice would be:
Stick with your current language and learn more techniques, such as a wider range of algorithms, functional programming, design by contract, unit testing, OOAD, etc.
learn C (focus on figuring out pointers, multi-dimensional arrays, data structures like linked lists, and resource management like memory allocation/deallocation, file handles, etc)
learn Assembly (on a modern platform with a flat memory architecture, but doing low-level stuff like talking to hardware or drawing on a canvas)
learn Python or Ruby. Chances are, you'll stick with one of these for a while, knowing all of the above, unless some hot new language has come along by then.
Why not learn some of each. Studying a language for a week or so won't make you an expert, but it will answer a lot of questions in your head and plant a seed for the future.
It's important to not just read through exercises. Find some simple problems that can be programmed in a page or two at most and solve them with each language. That will help you to learn the strengths and weaknesses in the context of the way you think and how you solve problems.
C++ is usually used when speed, and low-level OS access is involved.
It's a good skill to have if you want to expand.
Python allows you to do thing quickly, and it's quite easy to learn, and provides more power than you'd expect from a scripting language, and probably one of the fastest ones out there.
C++ isn't exactly slow to develop, if you've got an IDE, it's not hard to write per-se, but the syntax is going to get you.
If you want to apply to Google and/ or Microsoft then I'd say that of the two you need both!
Given more choice, probably C++ and one other language - either dynamic, functional, or both (Scala might be a good choice too).
It's not necessarily about whether you'd use the languages themselves but more about the different approaches they require and encourage.
If you continue to be "scared" by C++ you're probably going to struggle applying as a dev at either of those organisations - unless you are highly specialised elsewhere.
I think you just asked wrong question. It is not about the tool itself. It should be about what kind of software do you really find enjoying to create. C++ is used in creating different types of applications that are written in C# or Python. Please mind, that C# or .NET itself is not easy to learn. It may be quite easy to develop something that works somehow, but if you just delve into the details...
Anyway, my point is: if you're interested in developing web solutions: go for Python. There is a lot of hype about Python at the moment, and even Microsoft realized the power of this language (you may use your knowledge of .NET and Python programming using IronPython).
C++ is at the moment used in some specific areas. Business apps are written mostly in Java or .NET, and C++ is still great for more low level programming, in areas where performance is the crucial thing (and I mean 'performance' as performance of language/platform itself). The good example is game industry: Java and C# are definitely easier to learn than C++, but... how many 'big games' have been created entirely in C#/Java?
I have another advice for you: if you want to work for Microsoft or Google, do not focus on language itselft. It is NOT the most important thing. Focus on problem solving, algorithms and other stuff (Stevie Yegge's post about how to prepare for an interview at Google).
Oh, and of course as a fan of C++ (and C# too) I must admit that it is not true, that developing anything in C++ takes ages. You probably think of C++ as of "C with clasees" - take a look at STL, templates, advanced templates, Boost... Somehow all those people working in games industry manage to create better and better games in not so looooong time that takes others to create 'boring and easy' business app in Java/C#.
You might be interested in looking at Windows Powershell. It's the latest scripting technology from Microsoft, built on .NET, and can be extended via C#.
Granted, it's not as portable as C++ or Python, but it would leverage your C#/.NET experience more readily. Otherwise, I would suggest C++ (and possibly C). Microsoft builds a lot more of its products with C/C++ than with Python.
As someone familiar with C# and .NET you should consider IronPython. Python for .NET. This would be a good way to leverage what you know and learn a new dynamic language at the same time.

Is there a Functional Programming library for .NET?

For example, in Java there is Functional Java and Higher-Order Java. Both essentially give a small API for manipulating higher-order, curried functions, and perhaps a few new data types (tuples, immutable lists).
LanguageExt looks very promising for making functional style programming in C# easier.
https://github.com/louthy/language-ext
have you looked into F#?
Also a neat blog post would be here that talks about how to use the new generic / lambda expressions built into c# 3.0.
If you just add using System.Linq to the top of your source file there are a LOT of nice new functions added to working with collections such as folding / filtering / etc.
Assuming you can't use F# for whatever reason, and just want to use functional paradigms and idioms in your C# code to improve quality & reliability:
Functional style pattern matching for C#
Monad library for C#/.Net
There is also 'elevate' which has some functional things like option types (maybes) etc.
I think you want F#
Also, the more recent versions of C# have a lot of functional concepts included in the base langauge.
There may be such a library for C#, but you should probably consider just using F# http://research.microsoft.com/fsharp/fsharp.aspx and http://msdn.microsoft.com/en-us/fsharp/default.aspx.
Microsoft plans to make F# a first-class language in Visual Studio so there should be little risk in using one of the CTPs to build your initial stuff.
If you're looking for something that extends C# then no, but there is F# which is a .NET based functional language. From the "About F#" page:
F# is a typed functional programming language for the .NET Framework. It combines the succinctness, expressivity, and compositionality of typed functional programming with the runtime support, libraries, interoperability, tools and object model of .NET. F# stems from the ML family of languages and has a core language compatible with that of OCaml, though also draws from C# and Haskell. F# was designed from the ground up to be a first-class citizen on .NET, giving smooth interoperability with other .NET languages. For example, C# and F# can call each other directly. This means that F# has immediate access to all the .NET Framework APIs, including, for example, Windows Presentation Foundation and DirectX. Similarly, libraries developed in F# may be used from other .NET languages.
Since F# and OCaml share a similar core language, some OCaml libraries and applications can cross-compile either directly or with minor conditionally-compiled changes. This provides a path to cross-compile and/or port existing OCaml code to .NET, and also allows programmers to transfer skills between these languages. A major focus of the project has been to extend the reach of OCaml-like languages into arenas where they have not traditionally been used. Throughout the project the designers of F# are grateful for the support and encouragement of Xavier Leroy and others in the OCaml community.
Not a shrink-wrapped library per se, but Luca Bolognese of Microsoft has a series of blog posts where he builds a C# library for functional programming with types like tuples, records, type unions and so on:
Also Linq is basically a library for functional programming with syntactial support in C#.
Check out http://code.msdn.microsoft.com/FunctionalCSharp for some samples.
F#, there's a CTP release available from microsoft.
One more option to consider is FuncSharp. It's not so heavy as LanguageExt and it does cover the most important patterns/aspects.

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