For my university course I want to make system for learning programming. The main idea is writing code through debug, just look at picture (from Bret Victor video):
I don't want to make my own compiler (just becouse it's very complicated and hard, especially for C# language), so I want use all features of .NET and other libraries. I see there two ways:
Rewrite code by replacing assigments to assigment & sending debug information to main program
Compile code and debug it -> ...
Anyway, I need some start point. What classes and libraries I must google, in which manuals I can read useful information, what is the best way to implement it?
I think what could work is, if you just treat C# as a script language. There are multiple tutorials on how to use C# within C# as a script language, like this one. So you just start the "script" compiler again on predefined conditions (like a line break) and if the compilation is successfull you return the result in your second pane. This is just a basic idea.
Related
The customer has million lines of code (VB.Net and C#), and wants us to develop a tool to estimate the quality of the code.
What the information the customer wants to know include:
1）how many lines of comments in one code file
2) how many functions implemented in one class
3) whether all possible exception has been wrapped by a try/catch block
4) how many attributes attached to one function
5) ... (the customer said that the tool we provide should be configured and extensible so that they can implement more ideas later)
We plan to write a VS.Net add-on, which can parse the code of the opening project in time. seems the interesting thing in here is that we need to parsing the code of C# and VB.Net.
Please kindly provide some tips about how to start this interesting task.
Thanks in advanced!
You ask a very broad question, but you should begin by studying existing parser's APIs.
Once you do that you're golden.
For example look at this SO question which provides some parsers for C#. Of course you could write your own but I don't find any reason to since the task isn't very easy.
So you get your AST and once you do that you have all the information you want.
Keep in mind that if you reference a type that isn't in the file you must have to get it from another one, and it could also be a type from .NET. So there is definitely more work to be done.
To go through your list:
1）how many lines of comments in one code file: You could find it through your C# parser of choice. They recognize comment aswell
2) how many functions implemented in one class: Likewise, should be very easy
3) whether all possible exception has been wrapped by a try/catch block: Likewise, just find exception throws (the parser is likely to have a special type for language keywords, so looking for throw should be easy).
4) how many attributes attached to one function: and... Likewise
5) ... (the customer said that the tool we provide should be configured and extensible so that they can implement more ideas later): Shouldn't differ from any other project. Just make sure you're using good design principles, keeping everything abstract, using interfaces wisely, make your work in layers, etc. etc...
You can use Roslyn. For C# you can also use NRefactory.
Have a look at Stylecop, you may be able to add rules get the information you want?
http://stylecop.codeplex.com/
I’m trying to make CodeContracts in C# look more like statements so i need a tool that allows me substitute some code before the compiler sees it, if there is no way to do it i guess a Visual Studio plug in would help too.
Trying to fight the syntax of a language like C# is simply a bad idea. The tools you use will fight back with determination.
Just go with the flow and stop trying to swim against the current. You'll soon get used to the syntax and it will make sense to everyone else who works with the code.
You could always channel the code through a C++ preprocessor (like mcpp) before sending the code to the C# compiler. That would give you full power of C++ macros :)
I guess you could use a pre-build task to do that.
I use this approach in one project of mine (though it is not C#, but a quite different language, but I needed the C++ like macros).
What is wrong with the normal codecontracts ?
http://www.cauldwell.net/patrick/blog/CodeContracts.aspx
And
http://weblogs.asp.net/podwysocki/archive/2008/11/08/code-contracts-for-net-4-0-spec-comes-alive.aspx
What about expression trees?
Ok, so I was wondering how one would go about creating a program, that creates a second program(Like how most compression programs can create self extracting self excutables, but that's not what I need).
Say I have 2 programs. Each one containing a class. The one program I would use to modify and fill the class with data. The second file would be a program that also had the class, but empty, and it's only purpose is to access this data in a specific way. I don't know, I'm thinking if the specific class were serialized and then "injected" into the second file. But how would one be able to do that? I've found modifying files that were already compiled fascinating, though I've never been able to make changes that didn't cause errors.
That's just a thought. I don't know what the solution would be, that's just something that crossed my mind.
I'd prefer some information in say c or c++ that's cross-platform. The only other language I'd accept is c#.
also
I'm not looking for 3-rd party library's, or things such as Boost. If anything a shove in the right direction could be all I need.
++also
I don't want to be using a compiler.
Jalf actually read what I wrote
That's exactly what I would like to know how to do. I think that's fairly obvious by what I asked above. I said nothing about compiling the files, or scripting.
QUOTE "I've found modifying files that were already compiled fascinating"
Please read and understand the question first before posting.
thanks.
Building an executable from scratch is hard. First, you'd need to generate machine code for what the program would do, and then you need to encapsulate such code in an executable file. That's overkill unless you want to write a compiler for a language.
These utilities that generate a self-extracting executable don't really make the executable from scratch. They have the executable pre-generated, and the data file is just appended to the end of it. Since the Windows executable format allows you to put data at the end of the file, caring only for the "real executable" part (the exe header tells how big it is - the rest is ignored).
For instance, try to generate two self-extracting zip, and do a binary diff on them. You'll see their first X KBytes are exactly the same, what changes is the rest, which is not an executable at all, it's just data. When the file is executed, it looks what is found at the end of the file (the data) and unzips it.
Take a look at the wikipedia entry, go to the external links section to dig deeper:
http://en.wikipedia.org/wiki/Portable_Executable
I only mentioned Windows here but the same principles apply to Linux. But don't expect to have cross-platform results, you'll have to re-implement it to each platform. I couldn't imagine something that's more platform-dependent than the executable file. Even if you use C# you'll have to generate the native stub, which is different if you're running on Windows (under .net) or Linux (under Mono).
Invoke a compiler with data generated by your program (write temp files to disk if necessary) and or stored on disk?
Or is the question about the details of writing the local executable format?
Unfortunately with compiled languages such as C, C++, Java, or C#, you won't be able to just ``run'' new code at runtime, like you can do in interpreted languages like PHP, Perl, and ECMAscript. The code has to be compiled first, and for that you will need a compiler. There's no getting around this.
If you need to duplicate the save/restore functionality between two separate EXEs, then your best bet is to create a static library shared between the two programs, or a DLL shared between the two programs. That way, you write that code once and it's able to be used by as many programs as you want.
On the other hand, if you're really running into a scenario like this, my main question is, What are you trying to accomplish with this? Even in languages that support things like eval(), self modifying code is usually some of the nastiest and bug-riddled stuff you're going to find. It's worse even than a program written completely with GOTOs. There are uses for self modifying code like this, but 99% of the time it's the wrong approach to take.
Hope that helps :)
I had the same problem and I think that this solves all problems.
You can put there whatever code and if correct it will produce at runtime second executable.
--ADD--
So in short you have some code which you can hard-code and store in the code of your 1st exe file or let outside it. Then you run it and you compile the aforementioned code. If eveything is ok you will get a second executable runtime- compiled. All this without any external lib!!
Ok, so I was wondering how one would
go about creating a program, that
creates a second program
You can look at CodeDom. Here is a tutorial
Have you considered embedding a scripting language such as Lua or Python into your app? This will give you the ability to dynamically generate and execute code at runtime.
From wikipedia:
Dynamic programming language is a term used broadly in computer science to describe a class of high-level programming languages that execute at runtime many common behaviors that other languages might perform during compilation, if at all. These behaviors could include extension of the program, by adding new code, by extending objects and definitions, or by modifying the type system, all during program execution. These behaviors can be emulated in nearly any language of sufficient complexity, but dynamic languages provide direct tools to make use of them.
Depending on what you call a program, Self-modifying code may do the trick.
Basically, you write code somewhere in memory as if it were plain data, and you call it.
Usually it's a bad idea, but it's quite fun.
Creating a call stack diagram
We have just recently been thrown into a big project that requires us to get into the code (duh).
We are using different methods to get acquainted with it, breakpoints etc. However we found that one method is to make a call tree of the application, what is the easiest /fastest way to do this?
By code? Plugins? Manually?
The project is a C# Windows application.
With the static analyzer NDepend, you can obtain a static method call graph, like the one below. Disclaimer: I am one of the developers of the tool
For that you just need to export to the graph the result of a CQLinq code query:
Such a code query, can be generated actually for any method, thanks to the right-click menu illustrated below.
Whenever I start a new job (which is frequently as I am a contractor) I spend two to three days reading through every single source file in the repository, and keep notes against each class in a simple text file. It is quite laborious but it means that you get a really good idea how the project fits together and you have a trusty map when you need to find the class that does somethnig.
Altought I love UML/diagramming when starting a project I, personally, do not find them at all useful when examining existing code.
Not a direct answer to your question, but NDepend is a good tool to get a 100ft view of a codebase, and it enables you to drill down into the relationships between classes (and many other features)
Edit: I believe the Microsoft's CLR Profiler is capable of displaying a call tree for a running application. If that is not sufficient I have left the link I posted below in case you would like to start on a custom solution.
Here is a CodeProject article that might point you in the right direction:
The download offered here is a Visual
Studio 2008 C# project for a simple
utility to list user function call
trees in C# code.
This call tree lister seems to work OK
for my style of coding, but will
likely be unreliable for some other
styles of coding. It is offered here
with two thoughts: first, some
programmers may find it useful as is;
second, I would be appreciative if
someone who is up-to-speed on C#
parsing would upgrade it by
incorporating an accurate C# parser
and turn out an improved utility that
is reliable regardless of coding style
The source code is available for download - perhaps you can use this as a starting point for a custom solution.
You mean something like this: http://erik.doernenburg.com/2008/09/call-graph-visualisation-with-aspectj-and-dot/
Not to be a stuck record, but if I get it running and pause it a few times, and each time capture the call stack, that gives me a real good picture of the call structure that accounts for the most time. It doesn't give me the call structure for things that happen real fast, however.
I'm just starting out with C# and to me it seems like Microsoft Called their new system .Net because you have to use the Internet to look everything up to find useful functions and which class they stashed it in.
To me it seems nonsensical to require procedure/functions written and designed to stand alone ( non instantiated static objects) to have their class not also function as their namespace.
That is Why can't I use Write or WriteLine instead of Console.WriteLine ?
Then when I start to get used to the idea that the objects I am using ( like string) know how to perform operations I am used to using external functions to achieve ( like to upper, tolower, substring, etc) they change the rules with numbers, numbers don't know how to convert themselves from one numeric type to another for some reason, instead you have to invoke Convert class static functions to change a double to an int and Math class static functions to achieve rounding and truncating.. which quickly turns your simple( in other languages) statement to a gazillion character line in C#.
It also seems obsessed with strong typing which interferes somewhat with the thought process when I code. I understand that type safety reduces errors , but I think it also increases complexity, sometimes unnecessarily. It would be nice if you could choose context driven types when you wish without the explicit Casting or Converting or ToStringing that seems to be basic necessity in C# to get anything done.
So... Is it even possible to write meaningful code in notepad and use cl with out Internet access? What ref book would you use without recourse to autocomplete and Network access?
Any suggestions on smoothing the process towards grokking this language and using it more naturally?
I think you're suffering a bit from the fact that you've used to working in one way during some years, and now must take time to get yourself comfortable using / developing in a new platform.
I do not agree with you , that MS hasn't been consistent on the fact that a string knows how it should convert itself to another type, and other datatypes (like ints) do not.
This is not true, since strings do not know for themselves how they should be converted to another type as well. (You can use the Convert class to Convert types to other types).
It is however true that every type in .NET has a ToString() method, but, you should not rely on that method to convert whatever you have to a string.
I think you have never worked in an OO language before, and therefore, you're having some difficulties with the paradigm shift.
Think of it this way: it's all about responsabilities and behaviour. A class is (if it is well designed) responsible for doing one thing, and does this one thing good.
There is no excuse to use notepad to code a modern language. SharpDevelop or Visual C# Express provide the functionality to work with C# in a productive way.
And no, due to the complexity, not using the internet as a source of information is also not a good option.
You could buy a book that introduces you to the concepts of the language in a structured way, but to get up-to-date information, the internet is neccessary.
Yes, there are drawbacks in C#, like in any other language. I can only give you the advice to get used to the language. Many of the drawbacks become understandable after that, even if some of them don't become less annoying. I recommend that you ask clear, direct questions with example code if you want to know how some language constructs work or how you can solve specific problems more efficiently. That makes it easier to answer those questions.
For notepad, I have no useful advice, however I would advise you to use one of the free IDE's, Microsofts Express Editions, or Sharp Develop.
The IDE will speed the groking of the language, at which point, you can switch back to notepad.
Reading your post I was thinking that you worked mostly with C or dynamic languages previously. Maybe C# is just a wrong choice for you, there are IronPython, F# and a bunch of other languages that have necessary functionality (like functions outside of classes etc.)
I disagree with you about consistency. In fact there are small inconsistency between some components of .NET, but most part of FW is very consistent and predictable.
Strong typing is a huge factor in low defect count. Dynamic typing plays nice in small/intermediate projects (like scripts, etc). In more or less complex program dynamism can introduce a lot of complexity.
Regarding internet/autocomplete - I can hardly imagine any technology with size of .NET that doesn't require a lot of knowledge sources.
Programming in c# using notepad is like buying a ferrari to drive in dirt roads.
At least use Visual Studio Express Edition. For what you wrote I understand that you come from a non OO background, try to learn the OO concept and try to use it. You will eventually understand most design decisions made for .Net.
http://en.wikipedia.org/wiki/Object-oriented_programming
Oh boy where do i start with you(this will be a long post hahaha), well, lets go little by little:
"Microsoft called their system .NET because you have to use Intenet...", the reason why is called .NET is because the SUITE OF MICROSOFT LANGUAGUES(and now some other ones too like Phyton and Ruby, etc) CAN CALL ANY LIBRARY or DLLs, example you can "NET"(Network OR CALL) a DLL that was built in Visual Basic, F#, C++ from WITHIN C# or from any of those languagues you can also call(or ".NET") C# libraries. OK ONE DOWN!!!
NEXT ONE: "it seems nonsensical to require....to have their class not also function as their namespace", this is because a Namespace can have AS MANY CLASSES AS YOU WISH, and your question:
"That is Why can't I use Write or WriteLine instead of Console.WriteLine ?".
The reason is because: "Console"(System.Console hense the "Using" statement at the beginning of your program) Namespace is where "Write" and "WriteLine" LIVES!!(you can also FULLY qualify it (or "call It"). (all this seems to me that you need to study C# Syntax), ok NEXT:
"when I start to get used to the idea that the objects...", ok in simple words:
C# is a "Strongly Type-Safe language" so that SHOULD-MUST tell you what "you are getting in to" otherwise STAY WITH "WEAK or NO TYPE SAFE LANGUAGES" LIKE PHP or C , etc. this does NOT means is bad it just MEANS IS YOUR JOB TO MAKE SURE, as i tell my students: "IF YOU NEED AN INT THEN DEFINE AN INT INSTEAD LETTING THE COMPILER DO IT FOR YOU OTHERWISE YOU WILL HAVE A LOT OF BAD BUGS", or in other words do YOUR homework BEFORE DESIGNING A PIECE OF SOFTWARE.
Note: C# is IMPLICITY TYPE SAFE language SO IF YOU WANT YOU CAN RUN IT AS UNSAFE so from then it wiLL be your job to make sure, so dont complain later(for being lazy) when bugs arrive AT RUNTIME(and a lot of times when the customer is already using your crappy software).
...and last but not least : Whey do you wan to shoot yourself by using notepad? Studio Express is FREE, even the database SQL SERVER is FREE TOO!!, unless you work for a company I WILL ASK FOR PRO, ETC. all the "extra" stuff is for large companies, teams, etc, YOU CAN DO 99% OF THE STUFF WITH THE FREE VERSIONS(and you can still buy-update to full version once you want to scalate to Distributed Software or a Large Project, or if your software becomes a big hit, Example: if you need millions of queryes or hits PER SECOND from your database or 100 people are working on same project(code) but for the majority of times for 2 or 3 "normal" developers working at home or small office the FREE ONES ARE ENOuGH!!)
cherrsss!!! (PS: Software Developer since the 80's)