Inside a Java project I use Google Protocol Buffers (GPB) for serializing my objects. I can use the same .proto files in auxiliary Python code, which is great. Now I'm adding a Flex client to the whole thing and I'd like to use the same .proto files once more.
It seems there's a couple of projects out there which compile .proto files to Actionscript. From a few glances at the projects' homepages, it seems to me that protobuf-actionscript3 is actually the most advanced and most "alive" of these projects.
Has anybody had practical experience with GPB to AS3 compilers and which one(s) can you recommend (or recommend against)?
If you're sure you want to use GPB, then protobuf-actionscript3 is your best option. It builds on the semi-successful protocol-buffers-actionscript project: http://code.google.com/p/protocol-buffers-actionscript/
If you're open to looking at other formats, there's always Adobe's own AMF3. It seems to have a good amount of community support behind it.
The only choice now is https://code.google.com/p/protoc-gen-as3/. All the other Protobuf/AS3 projects are out-of-date, and lack of features.
Related
I have painfully come across the facts that scala.util.parsing and scala.swing are apparently no more bundled in Scala 2.11. Each time, I had to google for the right line to add to an sbt configuration, or to find the right link for where to download the jar file.
In case there are other libraries that moved out, how am I supposed to know these things? Or am I supposed to rely only on questions from people having the same problem on Stackoverflow? The Scala Swing project on github does not even document these info.
I like creating Eclipse projects on the fly, and making them depend on other projects in the same workspace, without going through sbt, and it is annoying to run into these library disappearance cases on every computer/workspace where I do this.
The modularization (what you call externalizing) has been discussed for a good while on the scala-users mailing list. But the canonical place where to find this information is in the release notes. While you may not want to read all of those, I would strongly advise reading at least the release notes for a major version of any language you use. Case in point, the release notes for Scala 2.11.0:
Modularization
The core Scala standard library jar has shed 20% of its
bytecode. The modules for xml, parsing, swing as well as the
(unsupported) continuations plugin and library are available
individually or via scala-library-all. Note that this artifact has
weaker binary compatibility guarantees than scala-library – as
explained above. The compiler has been modularized internally, to
separate the presentation compiler, scaladoc and the REPL. We hope
this will make it easier to contribute. In this release, all of these
modules are still packaged in scala-compiler.jar. We plan to ship them
in separate JARs in 2.12.x.
I am very new to Alchemy and not an expert in using swc to store code(Although I am well aware that it worked for me so far). I want to make sure I understand if Alchemy is the right tool for me in this situation.
I want to make a simple script in Alchemy to help make certain 'heavy lifting' in the code lighter and less time consuming and ooze out more performance. The trick is that my colleagues will likely be daunted by the installation process(even though there is a guide). So my question is, if I do take the time to work with Alchemey, can I make my code available to other people that do not use it, for our project?
Hope that makes sense, my instincts (gut feeling) says yes. I simply want to make sure.
Yes, this is exactly what SWCs are for, you can compile your C++ code with FlasCC and expose a simple AS3 API that other people can use by linking your SWC into their project. Download the FlasCC beta and check out the tutorials it comes with that explain this in more detail: http://gaming.adobe.com/technologies/flascc/
Shortly, the answer is yes.
The point is you can't recompile the SWC into an SWF if you don't use alchemy. What you can do, is download at runtime (using Loader.load with ApplicationDomain.currentDomain) the SWF contained into the SWF (SWC is a simple zip, extract it).
Then, you can freely use the class that's inside, using ApplicationDomain.getDefinition("OneOfYourClass).
More about application domain
Since it's at runtime, you won't have to compile Alchemy, thus it should work fine for anyone.
There are several packages out there that help in automating the task of writing bindings between C\C++ and other languages.
In my case, I'd like to bind Python, some options for such packages are: SWIG, Boost.Python and Robin.
It seems that the straight forward process is to use these packages to create C\C++ linkable libraries (with mostly static functions) and have the higher language be extended using them.
However, my situation is that I already have a developed working system in C++ therefore plan to embed Python into it so that future development will be in Python.
It's not clear to me how, and if at all possible, to use these packages in helping to extend embedded Python in such a way that the Python code would be able to interact with the various Singleton instances already running in the system, and instantiate C++ classes and interact with them.
What I'm looking for is an insight regarding the design best fitted for this situation.
Boost.python lets you do a lot of those things right out of the box, especially if you use smart pointers. You can even inherit from C++ classes in Python, then pass instances of those back to your C++ code and have everything still work. My favorite resource on how to do various stuff is this (especially check out the "How To" section): http://wiki.python.org/moin/boost.python/ .
Boost.python is especially good if you're using smart pointers or intrusive pointers, as those translate transparently into PyObject reference counting. Also, it's very good at making factory functions look like Python constructors, which makes for very clean Python APIs.
If you're not using smart pointers, it's still possible to do all the things you want, but you have to mess with various return and lifetime policies, which can give you a headache.
To make it short: There is the modern alternative pybind11.
Long version: I also had to embed python. The C++ Python interface is small so I decided to use the C Api. That turned out to be a nightmare. Exposing classes lets you write tons of complicated boilerplate code. Boost::Python greatly avoids this by using readable interface definitions. However I found that boost lacks a sophisticated documentation and dor some things you still have to call the Python api. Further their build system seems to give people troubles. I cant tell since i use packages provided by the system. Finally I tried the boost python fork pybind11 and have to say that it is really convenient and fixes some shortcomings of boost like the necessity of the use of the Python Api, ability to use lambdas, the lack of an easy comprehensible documentation and automatic exception translation. Further it is header only and does not pull the huge boost dependency on deployment, so I can definitively recommend it.
How does one study open-source libraries code, particularly standard libraries?
The code base is often vast and hard to navigate. How to find some function or class definition?
Do I search through downloaded source files?
Do I need cvs/svn for that?
Maybe web-search?
Should I just know the structure of the standard library?
Is there any reference on it?
Or do some IDEs have such features? Or some other tools?
How to do it effectively without one?
What are the best practices of doing this in any open-source libraries?
Is there any convention of how are sources manipulated on Linux/Unix systems?
What are the differences for specific programming languages?
Broad presentation of the subject is highly encouraged.
I mark this 'community wiki' so everyone can rephrase and expand my awkward formulations!
Update: Probably didn't express the problem clear enough. What I want to, is to view just the source code of some specific library class or function. And the problem is mostly about work organization and usability - how do I navigate in the huge pile of sources to find the thing, maybe there are specific tools or approaches? It feels like there should've long existed some solution(s) for that.
One thing to note is that standard libraries are sometimes (often?) optimized more than is good for most production code.
Because they are widely used, they have to perform well over a wide variety of conditions, and may be full of clever tricks and special logic for corner cases.
Maybe they are not the best thing to study as a beginner.
Just a thought.
Well, I think that it's insane to just site down and read a library's code. My approach is to search whenever I come across the need to implement something by myself and then study the way that it's implemented in those libraries.
And there's also allot of projects/libraries with excellent documentation, which I find more important to read than the code. In Unix based systems you often find valuable information in the man pages.
Wow, that's a big question.
The short answer: it depends.
The long answer:
Some libraries provide documentation while others don't. Standard libraries are usually pretty well documented, whether your chosen implementation of the library includes documentation or not. For instance you may have found an implementation of the c standard library without documentation but the c standard has been around long enough that there are hundreds of good reference books available. Documentation with hyperlinks is a very useful way to learn a new API. In any case the first place I would look is the library's main website
For less well known libraries lacking documentation I find two different approaches very helpful.
First is a doc generator. Nearly every language I know of has one. It basically parses an source tree and creates documentation (usually as html or xml) which can be used to learn a library. Some use specially formatted comments in the code to create more complete documentation. JavaDoc is one good example of this. Doc generators for many other languages borrow from JavaDoc.
Second an IDE with a class browser. These act as a sort of on the fly documentation. Some display just the library's interface. Other's include description comments from the library's source.
Both of these will require access to the libraries source (which will come in handy if you intend actually use a library).
Many of these tools and techniques work equally well for closed/proprietary libraries.
The standard Java libraries' source code is available. For a beginning Java programmer these can be a great read. Especially the Collections framework is a good place to start. Take for instance the implementation of ArrayList and learn how you can implement a resizeable array in Java. Most of the source has even useful comments.
The best parts to read are probably whose purpose you can understand immediately. Start with the easy pieces and try to follow all the steps that are hidden behind that single call you make from your own code.
Something I do from time to time :
apt-get source foo
Then new C++ project (or whatever) in Eclipse and import.
=> Wow ! Browsable ! (use F3)
I'm interested in making a language to run on the AVM2 and I'm looking for advice on where to start. I do realize that this is by no means a trivial task, but I would like to give it a try and at the very least learn more about implementing a language along the way.
I have messed around with ANTLR and have been reading up on syntax issues for language development. What I'm looking for is advice on a path to take or useful references/books.
For instance I would like to generate (script/manually) some very simple AVM2 bytecode and get that to run on the VM as a start.
Thanks
If you are not interested in Haxe, you will basically need to write your own compiler that compiles objects down to ABC (Actionscript Byte Code). The AVM2 Overview document available from Adobe on ABC and the AVM2 which should help you get started. It's a fairly thorough document but stay alert for a few typo's in the bytecode instructions.
You will also need to wrap the bytecode in a doABC tag as part of a SWF container. You can get more information from the SWF File Format documentation.
If you'd like a headstart on writing the data structures (optimised int formats, etc), feel free to checkout the code at asmock, a dynamic mocking project I've been working on. The SWF/ByteCode generation stuff is a bit messy but there are IDataOutput wrappers (SWF, ByteCode) that might come in handy.
Project Alchemy by Adobe can be a good reference
http://labs.adobe.com/technologies/alchemy/
How did it go?
I'm also interested in doing a Java to AVM2 compiler...
Do you have any published code?
Take a look at Haxe: it is an open source language that can target different platforms, including the AVM. You can dig into the SWF compiler source code to get some inspiration.