For an in-browser application written in ceylon-js it would be desirable to reduce the size of the ceylon.language-1.2.0.js file to only that what is actually needed.
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How to use ceylon js (also with google closure compiler)
But the given solution involves manually editing javascript code resulting from compilation. This is not desirable since a compiler should produce code that hasn´t to be edited manually after compilation (abstraction).
And it is not clear to me if google closure compiler can cope with the ceylon flavour of it in a reliable way.
Is it instead a solution to copy ceylon.language source in ceylon into the project and import only those parts of ceylon.language into the project that are required by it? Then compile to javascript. And then leave away ceylon.language-1.2.0.js at all from the client / in-browser application.
Now my questions:
What parts are needed in the most simple browser application? I think of something like Array(String) and the like.
Has that solution a chance to work absolutely reliable?
Will there be a better solution coming from the authors of ceylon that make this attempt obsolete?
The compilation of the language module to JS is a tricky process, because of the native stuff involved and because there are a couple of declarations that have to be in a certain order for things to work.
Minification is still pending, we are going to do it but it's not the highest priority right now, and we have to determine the best way to solve this problem; one option that has been discussed is to have a version of the language module without any metamodel info, for example.
Related
Note: this is not a dupe of this or this other question. Read on: this question is specific to the Code-Sharing template.
I am doing some pretty basic experiments with NativeScript, Angular and the code sharing templates (see: #nativescript/schematics).
Now I am doing some exploration / poc work on how different "build configuration" are supported by the framework. To be clear, I am searching for a simple -and hopefully official- way to have the application use a different version of a specific file (let's call it configuration.ts) based on the current platform (web/ios/android) and environment (development/production/staging?).
Doing the first part is obviously trivial - after all that is the prime purpose of the code sharing schematics. So, different versions of the same file are identified by different extensions. This page explain things pretty simply.
What I don't get as easily is if the framework/template supports any similar convention-based rule that can be used to switch between debug/release (or even better development/staging/production) versions of a file. Think for example of a config.ts file that contains different parameters based on the environment.
I have done some research in the topic, but I was unable to find a conclusive answer:
the old and now retired documentation for the appbuilder platform mentions a (.debug. and .release.) naming convention for files. I don't think this work anymore.
other sources mention passing parameters during the call to tns build / tns run and then fetching them via webpack env variable... See here. This may work, but seems oddly convoluted
third option that gets mentioned is to use hooks to customize the build (or use a plugin that should do the same)
lastly, for some odd reason, the #nativescript/schematics seems to generate a default project that contains two files called environment.ts and environment.prod.ts. I suspect those only work for the web version of the project (read: ng serve) - I wasn't able to get the mobile compiler to recognize files that end with debug.ts, prod.ts or release.ts
While it may be possible that what I am trying to do isn't just supported (yet?), the general confusion an dissenting opinions on the matter make me think I may be missing something.. somewhere.
In case this IS somehow supported, I also wonder how it may integrate with the NativeScript Sidekick app that is often suggested as a tool to ease the build/run process of NativeScript applications (there is no way to specify additional parameters for the tns commands that the Sidekick automates, the only options available are switching between debug/release mode), but this is probably better to be left for another question.
Environment files are not yet supported, passing environment variables from build command could be the viable solution for now.
But of course, you may write your own schematics if you like immediate support for environment files.
I did not look into sharing environment files between web and mobile yet - I do like Manoj's suggestion regarding modifying the schematics, but I'll have to cross that bridge when I get there I guess. I might have an answer to your second question regarding Sidekick. The latest version does support "Webpack" build option which seems to pass the --bundle parameter to tns. The caveat is that this option seems to be more sensitive to typescript errors, even relatively benign ones, so you have to be careful and make sure to fix them all prior to building. In my case I had to lock the version of #types/jasmine in package.json to "2.8.6" in order to avoid some incompatibility between that and the version of typescript that Sidekick's cloud solution is using. Another hint is to check "Clean Build" after npm dependency changes are made. Good luck!
(I defined this program in terms of a C++ program because I faced this thing while coding a C++ program, but the actual question is language-agnostic).
I had to copy chars from one char* buffer to another buffer. So, instead of doing a #include <cstring> for strcpy, I wrote a small snippet of code myself to do the same.
Here are the thoughts that I could think of then:
Standard library functions are generally the fastest implementations that one can find of a certain code.
But it would be unwise to include a big header file if you're going to use only a very minor part of it (that's what I think happens).
I want to know how right I was in doing so, and what can be defined as a bound of coding own snippets after which one should revert to using headers.
The first rule of thumb is "don't reinvent the wheel". And remember that your wheel will probably be worse :-) (there are very good programmers that write the wheel provided by your compiler).
But yes, if I had to include the whole boost library for a single function, I would try to directly copy it from the library :-)
I'll add that the question is marked as "language-agnostic", so we can't simply speak about the difference between C/C++ headers and C/C++ libraries. If we speak of a generic language, the inclusion of an external library COULD have side-effects, even BIG side-effects. For example it could slow down very much the startup of your program even if it isn't used (because it has static initializers that need to be called at startup, or it references flocks of other dll/dynamic libraries that need to be loaded). And it wouldn't be the first time there is an error in the startup of a program caused by the static startup of one of its dependancies :-)
So in the end "it depends". I would say that if only have to copy up to one file (let's say 250-500 lines) from a BSD source there isn't any big problem, for anything bigger linking to the library is probably necessary.
#include-ing a header file should have no effect on runtime performance. It may, of course, slow down your compiler.
A decent linker should only pull in the pieces that it actually needs.
When you are talking about performance what do you want to optimize ? Compile time, size of binary/object, speed of execution ?
Using a standard library has the big advantage to improve code Maintainability and Readability. If someone else has to review or modify your code, it is much better to use the "standard" way.
It is much easier to spot a bug when calling memcpy() or strncpy() than when calling MyMemCpy() or MyStringCpy()
I have a basic problem with knowing which classes to import for a given application, renderer, AS package, mxml component, etc. There seems to be hundreds of classes (both mx and flash) and I'm never sure which one(s) to import... so I just keep adding import statements until the errors go away. Is there a reference somewhere that I don't know about? Or does this just come with experience? Also... does importing a load of classes actually make the file size larger or does Flex only import the classes used nregardless of what I specify? If it only uses what is needed, why wouldn't everyone just do: import mx.*;
I would suggest that if you find yourself bringing in tons of imports, you should ask yourself: Does this class do to much?
It is less of a technical issue, and more of problem of object-oriented design -- maintainability, testability and stability.
I do my best to limit my external dependencies. I try to conform to SOLID principles that tell me that classes should exist for one reason. If a class does too much, it is a "code smell" and an indication that you should split it up.
How much is too much? It is tough to have a specific litmus test or limit... I just ask myself "What does this class do"? If my answer contains an "and" in it, then I consider splitting it up.
I think your problem is a not a real problem if you use any half decent IDE. If you're not using one, you probably should (even if it's not stricly necessary and you can write and compile with notepad and the command line).
If you are using Flex/Flash Builder, it will add the imports automatically (and remove the unneeded ones as well). Also, you can use Ctrl + SPACE to prompt autocomplete, which should add the necessary imports.
Flash Develop also manages this for you (the shortcut was Ctrl + Shift + 1 if I recall correctly, but I haven't used FD for a while).
There are other IDEs out there that I haven't personally used but also have this very basic feature.
If you're using the Flash IDE, well, it really sucks for writting code, so you should probably consider writting your code in some other less brain-dead editor if you plan to do anything more than a couple of lines of code here and there (again, you can write code in the Flash IDE but why not taking advantage of better tools when they're available?).
When you get an error, look at the API Reference for the class, and then either import the whole package or just the class you want. Highlighting the class and hitting F1 should also work (but I never search help this way).
As for file size, see my answer on Is it possible to dynamically create an instance of user-defined Class in Action Script 3?
As Juan pointed out, use FlashDevelop, it is a great (and free) IDE.
If you're using FlashDevelop with the Flex Compiler, you can compile straight from FlashDevelop, and use the refactoring tools they offer to slim down your imports.
Aside from that though, if you're not referencing them, they don't get compiled, so it's not like your compiled swf is any bigger.
I'm wrapping a C++ library in PHP using SWIG and there have been some occasions where I want to modify the generated code (both generated C++ and PHP):
Fix code-generation errors
Add code that makes sense in PHP, but not in C++ (e.g. type checking)
Add documentation tags (e.g. phpDoc)
I'm currently automating these modifications with patch. This approach works, but it seems high-maintenance and fragile. Is there a better way of doing this?
The best bet is to have your code generator generate correct code for your needs. Hand-tweaking generated output is unsustainable. You'll have to tweak it again any time the input changes.
If a tool is producing flatly erroneous output, it's ideal to repair it and submit patches back to the maintainer. If the output is correct for some circumstances but wrong for yours, I'd suggest to add an option that changes the behavior to what you need.
Sometimes, you can use a short program that automatically does an intelligent job of patching your generated code, so that you don't need a manual process to make patches.
Alternatively, you could write your own code generator, but I suspect that's much more work than you want. It also depends on what you're doing. Sometimes code-generation is really just macro-expansion, and there are plenty of good tools for that in the wild.
Good luck!
You may end up having a maintenance nightmare later on. Instead of SWIG you might consider using another generative approach that:
Let you add your custom code directly on the model (so that you won't need to add it post-generation)
Let you define your own generator. This feature alone could take out the need to add custom code all along.
The problem of using third-party generators is that they never really generate what you want. The problem of writing your own code generators is that it's much more work. You choose.
But correcting an automation with another automation...
Code generation is quite a wide topic and there are definitely many other approaches, which might be more interresting to you as mentioned above.
But if you do not want to use other tool, depending on what code is generated and on the PHP OO capabilities, you might use the Generation Gap pattern.
I'm creating a game in XNA and was thinking of creating my own scripting language (extremely simple mind you). I know there's better ways to go about this (and that I'm reinventing the wheel), but I want the learning experience more than to be productive and fast.
When confronted with code at run time, from what I understand, the usual approach is to parse into a machine code or byte code or something else that is actually executable and then execute that, right? But, for instance, when Chrome first came out they said their JavaScript engine was fast because it compiles the JavaScript into machine code. This implies other engines weren't compiling into machine code.
I'd prefer not compiling to a lower language, so are there any known modern techniques for parsing and executing code without compiling to low level? Perhaps something like parsing the code into some sort of tree, branching through the tree, and comparing each symbol and calling some function that handles that symbol? (Wild guessing and stabbing in the dark)
I personally wouldn't roll your own parser ( turning the input into tokens ) or lexer ( checking the input tokens for your language grammar ). Take a look at ANTLR for parsing/lexing - it's a great framework and has full source code if you want to dig into the guts of it.
For executing code that you've parsed, I'd look at running a simple virtual machine or even better look at llvm which is an open-source(ish) attempt to standardise the virtual machine byte code format and provide nice features like JITing ( turning your script compiled byte code into assembly ).
I wouldn't discourage you from the more advanced options that you machine such as native machine code execution but bear in mind that this is a very specialist area and gets real complex, real fast!
Earlz pointed out that my reply might seem to imply 'don't bother doing this yourself. Re-reading my post it does sound a bit that way. The reason I mentioned ANTLR and LLVM is they both have heaps of source code and tutorials so I feel this is a good reference source. Take it as a base and play
You can try this framework for building languages (it works well with XNA):
http://www.meta-alternative.net/mbase.html
There are some tutorials:
http://www.meta-alternative.net/calc.pdf
http://www.meta-alternative.net/pfront.pdf
Python is great as a scripting language. I would recommend you make a C# binding for its C API and use that. Embedding Python is easy. Your application can define functions, types/classes and variables inside modules which the Python interpreter can access. The application can also call functions in Python scripts and get a result back. These two features combined gives you a two-way communication scheme.
Basically, you get the Python syntax and semantics for free. What you would need to implement is the API your application exposes to Python. An example could be access to game logic functions and render functions. Python scripts would then define functions which calls these, and the host application would invoke the Python functions (with parameters) to get work done.
EDIT: Seems like IronPython can save you even more work. It's a C# implementation of CPython, and has its own embedding API: http://www.ironpython.net/