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I'm just getting back into OCaml for a new small research project after many years of SML, Haskell and F#.
I quickly found myself missing some things when using the OCaml libraries, and I also missed having a syntax for monadic comprehensions.
OCaml Batteries Included seems to fill exactly these gaps. But I'm a little unsure whether it has reached the point of being mature, stable and widespread enough for this project. Part of my doubt comes from having a number of hiccups when installing it - including discovering that currently the installation instructions are out of date, and it was only by Googling that eventually found a response to a support request that explained what was required.
Is Batteries relatively stable? (Or at least more stable than the above would suggest?)
Is its use relatively widespread? (E.g., is 10% of new OCaml code written using it?)
What kinds of projects would it be recommended for?
(And, in particular would it be recommended for a small-medium sized research project that should yield a small library that likely would be maintained for some time.)
Any other recommendations?
Semi-disclaimer: I am one of current developers of Batteries Included.
It hasn't seen a great deal of uptake yet so far as I know. I haven't seen any packages released that depend on it. However, that alone shouldn't stop you from using it. Hopefully it will gain some traction as it continues to mature. I personally use it for all of my new OCaml development, both for personal projects and for my research work.
Expect to see it in a fair amount of flux for the duration of the 1.x cycle. We're committed to keeping the APIs backwards-compatible for all 1.x releases, but new things will be added and old modules/functions likely deprecated. Much of it should be pretty stable, although we are still finding and fixing bugs. That will be greatly aided, though, by having more people use it and report the bugs we haven't seen yet.
We hope that the 2.0 release will be much more static and have a greater degree of consistency between modules, but 2.0 is likely a ways off.
My advice would be: if you would use Extlib, use Batteries. It has absorbed Extlib's feature set (indeed, most of its code), and fleshes it out quite a bit. If you find bugs, please report them :).
Well, I personally recommend OCaml Batteries Included. Of course, it just happens so that I'm the original author :)
The use is not widespread yet, but it's now part of Debian/testing and Ubuntu Lucid Lynx, in addition to GODI, so you can expect a number of people to test it for bugs.
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When having a new C++ project passed along to you, what is the standard way of stepping through it and becoming acquainted with the entire codebase? Do you just start at the top file and start reading through all x-hundred files? Do you use a tool to generate information for you? If so, which tool?
I use change requests/bug reports to guide my learning of some new project. It never makes a lot of sense to me to try and consume the entirety of something all at once. A change order or bug report gives me guidance to focus on this one tendril of the system, tracing it's activity through the code.
After a reasonable amount of these, I can get a good understanding of the fundamentals of the project.
Here's my general process:
Start by understanding what the application does, and how its used. (I see way too many developers completely skip this critical step.)
Search for any developer documentation related to the project. (However, realize this will nearly always be wrong and out of date - it just will have helpful clues.)
Try to figure out the logic in the organization. How is the main architecture defined? What large scale patterns are used? (ie: MVC, MVP, IoC, etc)
Try to figure out the main classes related to the "large" objects in the project. This helps for the point above.
Slowly start refactoring and cleaning up as you try to maintain the project.
Usually, that will get me at least somewhat up to speed. However, usually I end up given a project like this because something has to be fixed or enhanced, and timing isn't always realistic, in which case I often just have to jump in and pray.
Start working on it, perhaps by
adding a small feature.
Step through application startup in the debugger.
You could try running it through doxygen to at last give a browsable set of documentation - but basically the only way is a debugger, some trace/std::cerr messages and a lot of coffee.
The suggestion to write test cases is the basis of Working-Effectively-Legacy-code and the point of the cppunit test library. If you can take this approach depends on your team and your setup - if you are the new junior you can't really rewrite the app to support testing.
Try writing unit tests for the various classes.
There is one tool I know about that may help you, it's currently in beta called CppDepend that will help you understand the relation between the classes and the projects in the solution.
Other than that you can try to understand the code by reading it:
Start with the header (.h/.hpp) files, reading them would help understand the "interfaces" between the classes
If the solution has several project try to understand the responsibility of each project.
Find someone who is familiar with the project that could give you and overview, 5 min with the right person can save you an hour with the debugger
Understanding how the code is used is usually very helpful.
If this is a library, look at client code and unit tests. If there aren't any unit tests, write some.
If this is an application, understand how it works - in detail. Again read & write unit tests.
Essentially, it's all about the interfaces. Understand the the interfaces and you'll go a long way towards understanding how the code works. By interface, I mean, the API if it's a library, the UI if it's a graphical application, the content of the inbound & outbound messages if it's a server.
Firstly how large is large?
I don't think you can answer this without knowing the other half of the scenario. What is the requirement for changing the code?
Are you just supporting/fixing it when it goes wrong? Developing new functionality? Porting the code to a new platform? Upgrading the code for a new C++ compiler?
Depending on what your requirement is I would start in different ways.
Here's how I approach the problem
Start by fixing easy bugs. Do extreme dilligance on these bugs and use the debugger heavily to find the problem
Code review every change that goes into the system. On an unbelievably large system, pick a smaller subset and review all of these changes
And most importantly: Ask a lot of questions!
Things to do:
Look at what the sales brochure tells you it does, set the scope of your expectations
Install it, what options do you have in the installer, read the quick start/install guide
Find out what it does, does it even execute, do you have multiple executables
Is there a developer setup guide/wiki, pointers to VCS
Get the code and make your build environment work, document SDKs, build tools you need if it isn't already
Look at the build process, project dependancies, is there a build machine/CI service
Look at generated doc output (if there is any!)
Find an interesting piece of the solution and see how it works, what are the entry points/ how does it work/look for main classes and interfaces
Replicate bugs, stop at interesting features in the program to get an overview and work down to tracing code.
Start to fix things, but ensure you are fixing things by having appropriate unit tests to show that it is broken now and when it will be fixed.
I have been incorporating source codes from some mid-sized projects. The most important lesson I learn from this process is before going into the source codes, you must be sure what part of the source codes interest you most. You should then go into that piece by grepping logging/warning messages or looking at class/function names. In understanding the source codes, you should run it in a debugger or insert your own warning messages. In all, you should focus on things you are interested in. The last thing you want is to read all the source codes.
Try generating a documentation using Doxygen or something similar if it wasn't done already.
Walk through the API and see if there is something that is unclear to you and look at the code, if you still don't get it ask a developer who already worked on it before.
Always examine whatever you have to work on first.
Take a look at whatever UML documents you've got, if you don't have any:
Smack the developer/s who worked on it. It's a shame they didn't do something as basic as UML class diagrams.
Try to generate them from the code. They will not be accurate but the they will give you a head start.
If there is something specific that you don't understand or think is wrong, ask the team who developed it. They will probably know better.
Fixing bugs works just fine for any project, not just c++ one.
Browse around in the file hierarchy with Total Commander, try getting an overview of the structure. Try identify where the main header files are located. Also find the file where the main() function is located.
Ask a person who is already familiar with the codebase to outline the basic concepts that were used during development.
He doesn't need to explain every detail, but should give you a rough idea of how the software works and how the individual modules are connected with each other.
Additionally, what I've found useful in the past was to first setup a working development environment before starting to think about the code.
Read the documentation. If possible, speak with the former maintainer. Then, check out the code bases from the first commit and the first release from the VCS and spend some time looking at them. Don't go for full understanding yet, just skim and understand which are the major components and what they do. Then read the change logs and the release notes for each of the major releases. Then start breaking everything and see what breaks what. Do some bug fixes. Review the test suite and understand which component each test is focused on. Add some tests. Step through the code in a debugger. Repeat.
As already said, grab doxygen and build HTML documentation for source code.
If code is well-designed, you'll easily see a nice class hierarchy, clear call graphs and many other things that otherwise would take ages to uncover. When certain parts behavior appears unclear, look at the unit tests or write your own.
However, if the structure appears to be flat, or messy, or both together, you may find yourself in some sort of trouble.
I'm not sure there is a standard way. There are some for-pay tools that will do C++ class diagrams/call graphs and provide some kind of code-level view. doxygen is a good free one. My low-tech approach is to find the top-level file and start to sort through what it provides and how...taking notes if needed.
In C++, the most common problem is that a lot of energy and time is wasted on low level tasks, such as "memory management".
Things that are no - brainers in managed languages are a pain to do in C++.
I have been a Half-Life lover for years. I have a BS in CS and have been informally programming since High-School. When I was still in college I tried to become a mod programmer for fun..using the first Half-Life engine...didn't work so good. So i figured after all my great college learrning :-) I would have more insight on how to tackle this problem and could finally do it. So here I am..finally out in the business world programming java...so I downloaded the HL2 SDk and started looking through the class structure. I feel like I did that last time I tried this...dazed and confused. Sorry about all the back ground.
So what is the best way to systematically learn the code structure? I know java and I know c++..i just dont know what any of the classes do...the comments are few and far between and the documentation seems meager. Any good approahces? I **don'**t wanna start my own mod... I just wanna maybe be a spare-time mod programmer on some cool MOD one day...to keep the fun in learning programming along with the business side.
the comments are few and far between
and the documentation seems meager.
Any good approahces?
Welcome to the wonder that is the Source SDK. No, it's not documented. Experiment, hack, place breakpoints and see what happens if you change bits of code.
There is a wiki you may find helpful in some cases, but it's filled in by the community, and not by Valve, which means that you won't find any actual documentation there, just explanations of how previous modders have hacked the engine.
Honestly, it sucks. The only way around it is to dive in. Try to achieve various changes to the game and don't be afraid to rip the existing code apart. It won't be pretty, but if it works, who's going to complain? Their code is pretty horrible, and most likely, yours will be too.
You can start at the Valve Developer Wiki.
I think the best way is to check out the source code of one of the few open source mods out there, Open Source Jail Break. It will help you at least get familiar with the code.
Beyond that, its just developer resources and forums.
Edit:Plan of Attack seems great too.
Also: This is a great list, including both general and specific topics.
I'd do what I do with any other vague system... set lots of breakpoints and get a feel for the structure by watching it function. Add your own comments/documentation as you go. Test your understanding by making small changes and see if you get expected results.
I've worked with the Source SDK for a little and made some modifications. Really you have to have a good understanding of C and C++. The Source SDK isn't modern C++ and is much more akin to C with classes than any real OOP.
The SDK is simply fashioned in that the major of code is comprised of entities, of which many you can ignore.
Also know that the SDK uses inheritance very heavily, so look to base classes for functionality that you may desire.
I'd say make a list of important files and classes that maybe relevant to what you want to do with the SDK. Then start sorting these files using virtual folders in VS (or real folders on the filesystem) and use the find in files option (or grep) to find your way around.
Some sample files:
eiface.h - Engine interfaces
gameinterface.cpp/.h - Lots of interfaces from external dlls for server
cdll_client_int.cpp/.h - Lots of interfaces from external dlls for client
*_gamerules.cpp/.h - Gamerules (determines logic of game)
world.cpp - Entity that determines the map properties and loads the gamerules and other entities
Also try to use the Source SDK Base instead of the HL2MP Base for a mod. The former is a lot cleaner and easier to build off of.
Looking for some general advice...
I've been using boost for a while, and I've written several small modules and function (eg: see this SO question) which I think cold be appropriate for inclusion in boost. I've been to the project pages to see about the submission process, but it seems like it's "be on the inside, or don't bother". I can subscribe to the developers mailing list, but I'm not sure I'm qualified to post there: I'm certainly not intimately familiar with all the various boost modules, and not nearly as well-versed in template meta-programming as the people actively participating.
Is there an avenue that I'm missing for "normal" people to send ideas for things which could be incorporated into boost? Or is boost kinda a "open in name only, unless you make it a full-time job" type of project?
I think that you shouldn't hestitate and go to boost-devel. Most likely your code will not be accepted, but it is very likely that you will be able to collect valuable feedback and learn a lot. People there will justify why it can't be accepted in the current form, or how the given functionality could be made more generic, etc. I think that overall it will be beneficial for you.
If you are not comfortable with boost-devel then subscribe and just follow it for some time. And few more personal comments about reading/following the list:
Find out who is who - some people are active only in very narrow fields, while others tend to have a lot to say in many different domains
Create some kind of filtering rules for new mails (the load of the list is rather heavy) - some mails are really not interesting
Observe the review process of the submitted libraries, critical comments, suggestions.
Subscribe to boost-devel, boost and boost-users - they tend to be quite interconnected. You can throw sprit, threads and ublas lists if you are interested in these projects.
I have been following the devel list for some time. I feel as you do: maybe I am not playing in the same league as these people, but nevertheless you do learn quite a bit from the discussions there.
During the time I have been there, I have found some kind of common pattern for submissions: first query for interest in the library, then offer the library for review. Beware of the licensing of your code: if it is not compatible with the boost license most of the people will not even give it a look. Spending time in the review of some proprietary code seems like working for free for someone else.
Also consider writting docs and publishing, make the library accessible in the internet and have others use/look at it. That will boost (no pun intended) your chances.
Why does your stuff have to go straight into boost ? Why not just put it "out there" first with a license you're happy with... if there's enough interest in it from users a "hey this should be in boost" might be the next logical step, or not.
I tried submitting my UTF-8 CPP library to Boost. Started by subscribing to their dev mail list and sent a couple of informal review requests, but felt it leads nowhere so I gave up and never submitted a formal review request.
Good luck with your submission.
Did you look at http://www.boost.org/development/submissions.html?
Last term (August - December 2008) me and some class mates wrote an application in C++. Nothing spectacular, it is an ORM for Sqlite3. We implemented some stuff like reflection to make it work and release the end user from the ugly stuff. Personally, i think we made a nice job, and that our ORM could actually be useful for someone (even though its writen specifically for Sqlite3, its easily adaptable for oter databases).
Consequently, i`ve come to the conclusion that it should be published somewhere (sourceforge most likely) as an open source project. But, as it was a term project, there are some things that need to be addresesed before doing that. Namely, it has some memory leaks that should be fixed, and some parts of the code could be refactored to make everyone´s life easier in the future.
I would like to know more experienced C++ programmers opinion on some issues:
Is it worth rewriting some parts to
apply new techonologies (for example,
boost).
Should our ORM be adapted to latest
C++ standard? Is there any benefit in
doing this?
How will we know when our code is
ready for release?
What are the chances that this ORM
will be forgotten into the mists of
the internet? (i.e is it worth
publishing it beyond personal pride
as a programmer?)
Right now i can`t think of many more questions, but i would like to read on similar experiences.
EDIT: I should probably translate my code + comments to english right? (self question)
Thanks in advance.
I guess I am "more experienced" with regard to your particular question. I co-developed an open source web application language & template system a lot like ColdFusion back in the early days of web design before Java or ASP were around. You can still see it at http://www.steelblue.com/ if you are interested. It's still used at the company I was at when it was developed, but I don't think anywhere else.
What I found is that unless you are already well connected and people are watching what you are doing, getting people to use your open source code is just about as hard as selling somone your closed source program. You really need to advocate for your project and it should have some kind of unique selling proposition that distinguishes it from the compitition.
So, that's the unsolicited advice. Here are some specific answers to the questions you had...all purely my opinion, of course.
I wouldn't rewrite any code unless you have a featuer you want to put in. That feature might be compatibility with a specific platforms or compilers. It might be to support a new db datatype or smarter indicies or whatever. If you are going to put some more serious work into the applicaiton, think about a roadmap of what you can realistically accomplish in the next iteration and what choices will make the app the "most better" at the end of your cycle.
Release the code as soon as it is usable for a specific purpose, any purpose. Two reasons. First off, there might be someone who wants it for that purpose right now. If it's not available, they will use something else. Also, if it's open source, they might contribute back to the project. Second, the sooner you find out how much people want to use the code, the better. Either it will be more popular than you expect and you can get excited about continuing the development....or....you will find that no one is even visiting your web page to see what you've got. In either case, better to know sooner than later what people really want from your project so you can take that into account when planning new releases.
About the "forgotten into the mists." I think most projects are. I don't want to be a downer, but looking at Wikipedia, there were 5 C++ ORM tools popular enough to get mention and they were all open source. As I said above, unless you can sell your idea to people, they are going to go with another proven open source solution. For someone to choose you over them, three things have to happen: 1. They need a feature you have that the others don't. 2. They find your project web site and it demonstrates the superiority of your code. 3. They trust your code enough to give it a shot.
On the other hand, if you are in this for the long haul and want to continue development thigns get easier over time. Eventually the project will get all the basics covered and you can start developing those new featuers that aren't in the other solutions. Also, the longer you are in active development the more trustworthy the project will seem. Finally, you will get more experience in the nitch. 2 years from now you will be better positioned to say where your effort will have the most impact on bettering the project.
A final thought: If you are enjoying it, learning from it, and it's not getting in the way of you keeping food on the table, it's a good use of your time.
Good luck!
-Al
Regarding the open source part:
If you really want to make it an open source project, you really should publish it regardless of it's current state - fully working and debugged - or half working and full of memory leaks.
Just, if it's state is bad, make sure to document it, and give it a suitable version number (less than one?). then others may view your code, suggest improving, join your team, etc...
My--rather random--thoughts on the matter (in the order I think is most important):
How will we know when our code is ready for release?
Like Liran Orevi said: if you're going open source release early. Document it reasonable well, and take the time to provide a road map of planned or hoped for future improvements (these are a invitation for people to help you, so note which ones have no one working on them).
Is it worth rewriting some parts to apply new technologies (for example, boost).
Should our ORM be adapted to latest C++ standard? Is there any benefit in doing this?
SQLite relies on a fairly limited base. Maybe you don't want your tool to demand a much heavier environment. If the code in not currently a tangled and unmaintainable mess, you might want to avoid boost and newest frills. Once you have a stable release (1.0 at least) you can starting thinking about the improvements that can be made for version 2.
What are the chances that this ORM will be forgotten into the mists of the internet? (i.e is it worth publishing it beyond personal pride as a programmer?)
Most things end up in the big /dev/null in the sky, and there is only one way to find out... If it goes anywhere at all, you win. If it doesn't it was a modest investment, and maybe you learned something while you were at it.