Does Babel work with haskell and how do I do it? - haskell

I want to know if anyone has manage to integrate Haskell with other languages by using Babel.
Note: I'm putting three different question similar to these about other languages that I care about.
Note2: I did search before putting this question here. The problem is, Babel is used by to many projects and pages.

The Haskell guys at LANL might have something working, but other than that, I see no evidence of integration.

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A guide to Boo's metaprogramming and extensibility features?

I'm interested in learning about Boo's more powerful features such as syntactic macros, parser support (Ometa?), compiler pipeline, etc. My impression is that these areas have been in flux and somewhat under-documented. Are there any good resources for learning about these things other than studying the source code?
ask code gardener / boo author #rodgrigobamboo!
"boo metaprogramming facilities I - the ast".
There's Building Domain Specific Languages in Boo. I got an early early access edition and found it frustrating for the "flux" reason you mentioned; I finally gave up. Hopefully things have stabilized since then.
Feel free to ask questions on the mailing list:
http://groups-beta.google.com/group/boolang?pli=1
By far the best reference to see what Boo can do is to spend a bunch of time going through the tests. It takes a while to puzzle out what's going on, but the tests really do flex all of the muscles that are available and are quite well written.
https://github.com/bamboo/boo/blob/master/tests/testcases/macros/macro-1.boo
Also, note that boo's interpretter- booish- is really excellent and if you're not sure how a test works, you should probably spend time in booish prodding at it.
http://boo.codehaus.org/Interactive+Interpreter
I haven't looked through this site extensively, but it appears it may have the best references for Boo:
http://boo.codehaus.org/Tutorials
This section is still not well documented but if you look at https://github.com/bamboo/boo/wiki/Syntactic-Macros you can see how to make syntactic macros. Basically you have to implement Boo.Lang.Compiler.IAstMacro.
The correct section is in https://github.com/bamboo/boo/wiki/Abstract-Syntax-Tree but it largely seems incomplete.

Learning a language while on a project? [closed]

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Have you ever tried learning a language while on a project? I have, and from my personal experience I can say that it takes courage, effort, time, thinking, lots of caffeine and no sleep. Sometimes this has to be done without choice, other times you choose to do it; if you are working on a personal project for example.
What I normally do in this kind of situation, and I believe everyone does, is "build" on top of my current knowledge of languages, structures, syntax and logic. What I find difficult to cope with, is the difference of integrity in some cases. Some languages offer a good background for future learning and "language study", they pose as a good source of information or a frame of reference and can give a "firm" grasp of what's to come. Other languages form or introduce a new way of thinking and are harder to get used to.
Sometimes you unintentionally think in a specific language and when introduced to a new way of thinking, a new language, can cause confusion or make you get lost between the "borders" of your new and your current knowledge of languages.
What can be a good solution in this case? What should be used to broaden the knowledge of the new language, a new way of thinking, and maintain or incorporate the current knowledge of other languages inside the "borders" of the new language?
I find I need to do a project to properly learn a language, but those can be personal projects. When I learned Python on the job, I first expected (and found) a significant slowdown in my productivity for a while. I read the standard tutorials, coding standards and I lurked on the Python list for a while, which gave me a much better idea of the best practices of the language.
Doing things like coding dojos and stuff when learning a language can help you get a feel for things. I just recently changed jobs and went back to Java, and I spent some time working on toy programs just to get back in the feel for things (I'm also reading Effective Java, 2nd edition as my previous major experience had been with Java 1.4).
I think, in some respects no matter what the impetus for learning the language, you have to start by imitating good patterns in the new language. Whether that means finding a good book, with excellent code examples, good on-line tutorials, or following the lead of a more experienced developer, you have to absorb what it means to write good code in a particular language first. Once you have developed a level of comfort, you can start branching out and and experimenting with alternatives to the patterns that you've learned, looking for ways to apply things you've learned from other languages, but keeping within the "rules" of the language. Eventually, you'll get to the point where you know you can 'break the rules" that you learned earlier because you have enough experience to know when they do/don't apply.
My personal preference, even when forced to learn a new language, is to start with some throw away code. Even starting from good tutorials, you'll undoubtedly write code that later you will look back on and not understand how stupid you could have been. I prefer, if possible, to write as my first foray into a language code that will be thrown away and not come back to haunt me later. The alternative is to spend a lot of time refactoring as you learn more and more. Eventually, you'll end up doing this, too.
I would like to mention ALT.NET here
Self-organizing, ad-hoc community of developers bound by a desire to improve ourselves, challenge assumptions, and help each other pursue excellence in the practice of software development.
So in the spirit of ALT.NET, it is challenging but useful to reach out of your comfort zone to learn new languages. Some things that really helped me are as follows:
Understand the history behind a language or script. Knowing evolution helps a lot.
Pick the right book. Research StackOverflow and Amazon.com to find the right book to help you ease the growing pains.
OOP is fairly common in most of the mature languages, so you can skip many of the chapters related to OOP in many books. Syntax learning will be a gradual process. I commonly bookmark some quick handy guides for that.
Read as many community forums as possible to understand the common pitfalls of the new language.
Attend some local meetups to interact with the community and share your pains.
Take one pitch at a time by building small not so complicated applications and thereby gaining momentum.
Make sure you create a reference frame for what you need to learn. Things like how security, logging, multithreading are handled.
Be Open minded, you can be critical, but if you hate something then do not learn that language.
Finally, I think it is worthwhile to learn one strong languages like C# or Java, one functional language and one scripting language like ruby or python.
These things helped me tremendously and I think will help all software engineers and architects to really gear for any development environment.
I learned PHP after I was hired to be the project lead on the Zend Framework project.
It helped that I had 20 years of professional programming background, and good knowledge of C, Java, Perl, JavaScript, SQL, etc. I've also gravitated towards dynamic scripting languages for most of my career. I've written applications in awk, frameworks in shell, macro packages in troff, I even wrote a forum using only sed.
Things to help learn a language on the job:
Reading code and documentation.
Listening to mailing lists and blogs of the community.
Talking to experts in the language, fortunately several of whom were my immediate teammates.
Writing practice code, and asked for code reviews and coaching.(Zend_Console_Getopt was my first significant PHP contribution).
Learning the tools that go along with the language. PHPUnit, Xdebug, phpDoc, phing, etc.
Of course I did apply what I knew from other programming languages. Many computer science concepts are language-universal. The differences of a given language are often simply idiomatic, a way of stating something that can be done another way in another language. This is especially true for languages like Perl or PHP, which both borrow a lot of idioms from earlier languages.
It also helped that I took courses in Compiler Design in college. Having a good foundation in how languages are constructed makes it easier to pick up new languages. At some level, they're all just ways of abstracting runtime stacks and object references.
If you're a junior member of the team and don't know the language, this is not necessarily an issue at all. As long as there is some code review and supervision, you can be a productive.
Language syntax is one issue, but architectural differences are a more important concern. Many languages are also development platforms, and if you don't have experience with the platform, you don't know how to create a viable solution architecture. So if you're the project lead or working solo, you'd better have some experience on the platform before you do your design work.
For example, I would say an experienced C# coder with no VB experience would probably survive a VB.NET project just fine. In fact, it would be more difficult for a developer who only had experience in C#/ASP.NET to complete a C# WPF project than a VB ASP.NET project. An experienced PHP developer might hesitate a bit on a ColdFusion project, but they probably won't make any serious blunders because they are familiar with a script based web development architecture.
Many concepts, such as object modelling and database query strategies, translate just fine between languages. But there is always a learning curve for a new platform, and sometimes it can be quite nasty. The worst case is that the project must be thrown out because the architure is too wrong to refactor.
I like to learn a new language while working on a project, because a real project will usually force me to learn aspects of the language that I might otherwise skip. One of the first things I like to to is read code in that language, and jump in. I find resources (such as books and various internet sites) to help as I go along.
Then, after I've been working on it for a while, I like to read (or re-read) books or other resources on the language. By this time I have some knowledge, so this will help solidify some things and also point out areas where I am flat-out wrong in my understanding. For instance, I can see that I was making incorrect assumptions about similarities between languages.
This also applies to tools -- after using a tool for a while and learning the basics, reading (or skimming) the documentation can teach me a lot.
In my opinion, you should try to avoid that. I know, most of the times you can't but in any case try not to mix the new language with the old one, and never add to the mixture old habits, practices and patterns.
Always try to find resources that will help you get through the new language in the way the language works, not in the way other languages do; that will never have a happy ending, and if it does it will be very hard to modify it to the right way.
Cheers.
Yes I have.
I mean, is there another way? The only language I ever learned that was not on a project was ABC basic, which was what you used on my first computer.
I would recommend if you start with a certain language, stick with it. I only say that because many times in the past I tried more and more different ones, and the one I started out with was the best :D
Everytime I have/want to learn a new language, I force myself to find something to code.
But to be sure I did it well, I always want to be able to check my code and what it ouputs.
To do so, I just try to do the same kind of stuff with languages I know and to compare the outputs. For that, I created a little project (hosted on Github) with an exercise sheet and the correction for every language I learnt. It's a good way to learn in my opinion because it gives you a real little project.

What programming concept/technique has boosted your productivity? [closed]

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I've been programming for several years now and since then I have learned several concepts and techniques that have made me a better programmer (i.e. OOP, MVC, regex, hashing, etc). I feel too that by been able to learn several languages (basic, pascal, C/C++, lisp, prolog, python) I have widen my horizons in a very possitive way. But since some time ago I feel like I'm not learning any new good "trick". Can you suggest some interesting concept/technique/trick that could make me retake the learning flow?
A good paradigm shift always allows you to see things differently and become a better developer. I would suggest you read up on functional programming and maybe learn a functional language like Haskell or Scheme.
YAGNI (You Ain't Gonna Need It) and DTSTTCPW (Do The Simplest Thing That Could Possibly Work)
It's easy to spend a lot of time thinking about edge cases, and find that you've implemented something that's completely useless. I believe that a far better approach is to knock out a simple prototype, and then poke and prod it until you understand the domain well enough to create production code.
Recognize, however, that your prototype is going to evolve into production code whether you like it or not. So write it with that in mind.
Learning how to use your IDE and tools. This to me resulted in a far greater productivity increase.
For examples:
learning how to use a source level debugger
using tools like purify/boundschecker
fxcop
etc. I realize I am dating myself, but those were big steps. There are many more.
Any time you can change the way you think about a problem or solve a problem without having to undo previous work is HUGE gain. Process, tools, etc all can help with that. Don't limit yourself to finding silver bullet techniques for productivity gains.
Watching productive people work and getting them to tell you what they are doing and why is also invaluable.
If I'm honest, using, and learning a great framework like .NET has really increased my productivity.
I'm often amazed what people are willing to reinvent due to their ignorance that the very same function already exists in the framework.
AGILE and especially Test Driven Development. Best thing to happen to software development since the invention of Object Oriented Design.
Concerning coding, I'd say design patterns and architecture patterns are always nice to look at and can help you write cleaner/better code.
For methodology I would advice Agile development that is great. There are a numerous number of techniques and methods (I'm personally fan of extreme programming) and reading that can keep you busy and improve your general approach.
Finally I'd say learn new languages like Ruby
Design patterns
SCRUM process
DiSC assessment (and understanding of how it applies to collaborative s/w development)
StackOverflow.com (of course!)
Google
... other stuff too, I'm sure
Design Patterns. Learning how to break dependence upon implementation and inheritance, and depending on interfaces (contracts) instead changed the way I think about programming.
Debugging. Once I figured out how to actually step through the code and go line-by-line, examining the underlying state, it revolutionized how I troubleshoot code.
Practice, practice practice: I didn't realize how important it is to keep working on my skills apart from work until a relatively short time ago. Mistakes and solutions I make at home make me a better programmer at work, and vice a versa. Learning should never stop if you want to be good at something, and programming isn't an exception.
If I had to pick just one, I'd say Test-Driven Design, aka TDD: write unit tests (and check that they fail) before you incrementally add features.
Try to learn to see things from the user's standpoint.
For example:
learn how to write meaningful error messages
learn how to produce usable applications
learn some basic speed-optimization techniques
Remember that the user sees your application, not your code.
VIM Quick Reference Card. After I started using advanced vim (macros, plugins) I have stopped doing any repetitive actions during coding manually.
Apart from that, Scrum and working at night, when noone interrupts You gave me the highest benefit.
If you want to expand your experience into web programming, you should try and get a good handle on the HTTP Request/Response paradigm. This will make creating web apps much easier on you because you understand the underlying framework.
(http)://en.wikipedia.org/wiki/Hypertext_Transfer_Protocol
I would look at some of the newer languages that combine OO and functional elements, like C# or Scala.
Learning Smalltalk has helped me become more productive. It is an easy language to learn and things can be built extremely quickly. For a stunning productivity aid check out Seaside, it's a framework for building web applications. Moreover, if you have only been used to curly brace languages Smalltalk will also make you smile!
I was helped by the following paradigms in this order:
1) bottom-up programming
2) top-down programming (C, Pascal)
3) object-oriented programming (Smalltalk, Java)
4) functional programming (lisp, Mathematica)
with some logic programming thrown in (prolog).
nHibernate hands down. The fact that I dont need to write database functionality for my business objects is very useful and time saving.
High level understanding, creating good abstractions with proper dependencies, is what pays off in long term. For example, Law of Demeter is an important guideline. I recommend also reading Eric Evan's Domain Driven Design
Code generators. They're the best thing in software engineering.
Would you like to write all your projects in asm? Nope, let's generate it from C++. Or from something sat above the JVM which diligently generates the necessary machine code.
Duplicating the same source code all over the place, but stuck with a language that insists on the line noise? Use macros.
Want to use lambdas in a language that doesn't have them? Work out how to fake the anonymous name and variable scoping required then generate the boilerplate.
None of the readily available languages quite fit your pattern of thought, desired syntax or even semantics? Write a compiler for a new one.
Better languages are nice. Better design patterns are nice. Emacs is awesome. But compilers are where all the power lies in our field. I suspect the only reason they aren't mentioned in any of the other answers is that we can't imagine programming without any.
Copy/paste technique

Understanding a Large, Undocumented Set of Source Code? [closed]

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I have always been astonished by Wine. Sometimes I want to hack on it, fix little things and generally understand how it works. So, I download the Wine source code and right after that I feel overwhelmed. The codebase is huge and - unlike the Linux Kernel - there are almost no guides about the code.
What are the best-practices for understanding such a huge codebase?
With a complex code base the biggest mistake you can make is trying to be a computer. Get the computer to run the code, and use a debugger to help find out what is going on.
Figure out how to compile, install and run your own version of Wine from the existing source code.
Learn how debug (e.g. use gdb) on a running instance of your version of Wine.
Run Wine under the debugger and make cause it to demonstrate the undesired behaviour.
The fun part: find where the code execution path goes and start learning how it all goes together.
Yes, reading lots and lots of code will help, but the compiler/debugger/computer can run code a lot faster than you.
A professor once told us to compare such a situation with climbing a mountain. You might be listening to someone who did this and tells you what it's like to look out into the country. And you believe without hesitation that that's a spectacular sight.
However, you have to start climbing yourself for real understanding what the view from the top is like.
And it's not that important to climb all the way to the top. It might be perfectly suficient just to reach a fair height above ground level.
But don't ever be afraid of start climbing. The view is always worth any efforts.
This has always been a nice analogy for me. I know this question was more about specific tips on how to efficiently deal with code bases once you started climbing. But nevertheless it instantly reminded me of our physics classes way back then.
(This is an answer I posted to a question a while back. I modified it a bit to fit this question.)
Experience has shown me that there are 3 major goals you have when learning a legacy system:
Learn what the code is supposed to do.
Learn how it does them.
(crucially) Learn why it does them the way it does.
All three of those parts are very important, and there's a few tricks to help you get started.
First, resist the temptation to just ctrl-click (or whatever your IDE uses) your way around the code to understand everything. You probably won't be able to keep everything in perspective in your mind this way, especially when each line forces you to look at multiple other classes in order to understand what it is, so you need to be able to hold several levels of the stack in your head.
Read documentation where possible; it usually helps you quickly gain a mental framework upon which to build everything that follows.
Run test cases where possible.
Don't be afraid to ask someone who knows if you have a question. Granted, you shouldn't waste others' time with inane queries, but if there's something that you simply don't understand (this is especially true with more conceptual questions like, "Wouldn't it make much more sense to implement this as a ___" or something), it's probably worth finding out the answer before you mess something up and don't know why.
When you do finally get down to reading the code, start at a logical "main" place and go from there. Don't just read the code top to bottom, or in alphabetical order, or anything (this is probably obvious).
The best way to get acquainted with a large codebase is to dive in. Many projects have a list of easy tasks that need to be done, and they're usually reserved to help ease people in. You should find and work on some of these; you'll learn a lot about the general code outline and structure, contribute to the project, and get an easy payoff that will help encourage you to take on larger tasks.
Like most projects, WINE has good resources available to its developers; IRC, wiki, mailing list, and guides/overviews. With most daunting codebases, it's not so scary after the first few fixes. WINE is truly large, and much like the kernel, I doubt there's any expert in all systems; don't feel like you need to be either. Start working on something that matters to you and take it from there.
I've started a few patches to WINE myself, and it's a good community and good structure. There's lots of very helpful debug messages, and it's a really cool project to work on, so that helps you hit it longer too.
We all appreciate your valor and willingness to help with WINE (it needs it). Thanks, and good luck.
Dig in. Think of a question you'd like to have answered, and try to find the answer. When you get tired of reading code, go read the dev mailing list, the developer's guide, or the wiki.
Unfortunately, there's no royal road to understanding a large code base. If you enjoy that sort of thing (I do) you're in for some fun. If not, guide books won't really help, so you aren't really that much worse off.
Look for one peculiar feature you are interested to improve. Search for its implementation. Once you found it, pull on that straw and all the rest will follow.
The best way is through comments.
I'm being ironic, as you understand tiny bits of the beast add comments so you can follow your trail.
The other developers will also enjoy it if you add the missing guides in the code.
Try to implement some tiny little change in the code, something that will be visible to you. That might be figuring out a workable way to output debugging statements (and figuring out where the output appears), it might be changing the default size of windows or desktop color, or something. Once you can make something happen in the codebase, you've scratched the surface of understanding and can begin to move on toward more complicated things. At that point, select a goal of something slightly more useful that you'd like the code to do, and implement that. Or check out the project's bug tracker and look for something small to start with.
Document as you go, and write unit tests as you go, and refactor as you go. When you figure out what a routine does, comment it!!
As others have suggested, dig in! Read all the available documentation you can absorb. Then see if you can find other people who are interested or knowledgeable and learn with/from them. It helps to have people to bounce ideas off of and ask questions.
For C source code, once you get a feel for what areas of the code you'd like to work on, generate ctags and cscope databases for that code. These tools make it a lot easier to jump around and understand the code. Many text editors (one example is gvim) have support for ctags and cscope so you can jump around easily.
(warning: shameless marketing ahead)
For Java developers using Eclipse, there's nWire. It is an Eclipse plugin for navigating and visualizing large codebases.
A good way to understand a large system is to break it down into it's constituent parts and focus on a specific paths through the application.
Your debugger is your friend here, set a breakpoint in the thread you want to investigate then step through it line by line looking at which each part does... hope that helps...

How can I use functional programming in the real world? [closed]

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Functional languages are good because they avoid bugs by eliminating state, but also because they can be easily parallelized automatically for you, without you having to worry about the thread count.
As a Win32 developer though, can I use Haskell for some DLL files of my application? And if I do, is there a real advantage that would be taken automatically for me? If so, what gives me this advantage? The compiler?
Does F# parallelize functions you write across multiple cores and CPUs automatically for you? Would you ever see the thread count in Task Manager increase?
How can I start using Haskell in a practical way, and will I really see some benefits if I do?
It seems like the book Real World Haskell is just what you're looking for. You can read it free online.
F# does not contain any magic pixie dust that will pass functions off to different CPUs or machines. F#/Haskell and other functional programming languages make it easier for you to write functions that can be processed independent of the thread or CPU they were created on.
I don't feel right posting a link here to a podcast I participate in. It seems a little off, but in the Herding Code episode, where we talked with Matt Podwysocki, we asked the same question and he gave some interesting answers. There are also a lot of good links relating to functional programming in that episode. I found one link titled "Why Functional Programming Matters". That may provide some answers for you.
This might also be interesting:
"Real World Functional Programming"
Examples are in F# and C#, but the theory is fairly generic.
From what I've read (pre-release) it is definitely interesting, but so far I think it is making me want to stick more and more with C#, using libraries like Parallel Extensions.
You didn't mention, but I'm assuming, that you're using C++. One potentially easy way to get into functional is via C++/CLI to F#. C++ contains "magic pixie dust" (called IJW: It Just Works) to allow you to call into and out of managed code. With this, calling F# code is almost as simple as it is from C#.
I've used this in one program (FreeSWITCH), which is written entirely in C/C++. With a single managed C++/CLI (use the /clr switch), it magically transitions into managed code, and from there, I can go load my F# plugins and execute them. To make things even easier for deployment, F# can statically link all its dependencies, so you don't need to deploy the F# runtime files. One other thing that makes CLR code attractive is that you can pass managed code (delegates) to C code, and the runtime automatically makes a thunk for you.
If you decide to go the Haskell way, the feature you'll be looking for is FFI: Foreign Function Interface. However, I don't think it'll give you the same level of integration as C++/CLI with F#.
I'm currently learning Haskell myself. When you start out learning it, it doesn't seem very intriguing, because the learning experience is nothing like learning a language like C#.
It's a whole new world, but I noticed I could write very very complex expressions in just a few lines of code. When I looked back at the code, it was much more concise; it was small and tight.
I'm absolutely loving it! You can indeed write real-world programs that will be smaller, easier to maintain, and much more complex than most other languages allow. I vote for you to learn it!!
Since you mention Win32 and DLLs, I presume you're working with unmanaged code. In that case, GHC will work very well for you. Late last year I wrote a DDE server under Windows using FFI to talk to the Microsoft DDE libraries, and, surprisingly, it was an extremely pleasant experience (especially given that I'm a Unix guy).
Haskell's FFI is powerful (even supporting, e.g., callbacks into Haskell functions from C or other libraries), and having Haskell's type checking when writing C-level code is like a dream come true.
That last point is one of the major advantages of Haskell: the type system is amazing. That said, it's like any powerful tool; it needs time and effort to make good use of it.
So yes, it is possible to start out writing small bits of code in Haskell that link into the rest of your code (though you may find it easier to start with small Haskell programs that link to your other code), and it's well worth spending a fair amount of time learning about this and using it wherever you can. You may end up like me, planning a fairly major project tightly integrated with Windows code (in my case, a sophisticated Excel add-in) in Haskell.

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