This is the talk page for discussing improvements to the Vala (programming language) article. This is not a forum for general discussion of the article's subject. |
Article policies
|
Find sources: Google (books · news · scholar · free images · WP refs) · FENS · JSTOR · TWL |
This article is rated Start-class on Wikipedia's content assessment scale. It is of interest to the following WikiProjects: | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
Why create a new instance of itself with a "run" function instead of typing stdout.printf from the static main? —Preceding unsigned comment added by 88.218.24.29 (talk) 17:45, 18 December 2007 (UTC)
If it should be as simple as possible, we should use something like this:
using GLib;
void main () {
print ("Hello World\n");
}
However, it would be useful to have a second example, then, that shows a bit more of the syntax. Juergbi (talk) 14:14, 22 June 2008 (UTC)
void main() { print("Hello World\n"); }
Can somebody highlight the pros of using Vala, compared to using C++/gtkmm? —Preceding unsigned comment added by 82.238.35.175 (talk) 10:10, 10 February 2008 (UTC)
Pros:
- Vala generates C code that relies on GLib/GObject for it's object system. Benchmarks show that generated Vala code is generally as fast or faster than hand-coded C++ (see link at bottom of article).
- Vala also makes it extremely easy to use external C libraries: you just have to wrap the header in a Vala API file (called a VAPI), and declare what functions you'll be using. There are already a bunch of VAPIs for GNOME related stuff like libglade and gstreamer.
- I think it's worth pointing out that C++ can call the C libraries without any need to wrap the API in most cases. Vala just makes it easy to wrap the C API to fit into Vala's OOP style. Losinggeneration (talk) 10:01, 27 February 2009 (UTC)
- You at least need to extern "C" {} the callee and include the C header. 24.243.3.27 (talk) 08:50, 24 March 2009 (UTC)
- Still one of the big advantages of C++ is you can usuaully just include the C header in an extern "C" block (unless the C header trys to get really fancy). With most other languages you have to actually translate the imports (and home the library authors don't change them. Plugwash (talk) 19:46, 24 April 2009 (UTC)
- How does C++ prevent upstream from changing the library API? Sure, you get the functions for free by including the header, but if upstream changes the API on you, you get something like "implicit redefinition of function foo: original definition was in foo.h". But I agree that C++ has the tightest binding to the C ABI. So while it is not a Con against C++, it is still a Pro for Vala that it has a nice FFI for C. 64.234.67.2 (talk) 05:09, 27 May 2009 (UTC)
- Vala also makes it easy to write C libraries -- you can use Vala to write libraries, compile them to C files, then distribute the C files. Vala can even generate a VAPI for the library along with the C files, so that you can use the compiled library from Vala -- i.e., you can use Vala to write a C library that can be used from any application with a C ABI and natively from Vala itself (the tutorial shows an example of this near the bottom).
- Since it is so tightly coupled with Glib/Gobject it obviously make it easier working with libraries that also use GLib/GObject.
- It's syntax is almost identical with C# (even has delegates and signals [think events]). I like this syntax *much* better than C++, personally, but that's subjective.
Cons:
- Vala is relatively young and doesn't have the huge use base and community support that C++ does.
- Vala has very sparse documentation in many places (just the method names with no description, no descriptions of the parameters except their names, &c).
- There is alot of existing C++ code that can be reused, not so much with Vala (although they have a pretty good sized list of examples on the front page).
- The VAPIs are a work in progress (e.g., glib-2.0.vapi doesn't wrap g_chdir [but see below]).
[CCode (cname = "g_chdir")] public static int chdir (string pathname);
DirUtils.chdir( "/foo/bar" );
It appears to me that the section with the generated code does not fit the philosophy of wikipedia. Including more features of the language seems to me to be much more suitable. Any one minds me erasing that section? --Pmg (talk) 08:17, 17 June 2008 (UTC)
I deleted the generated code. It's completely inappropriate for an encyclipedia article.--Fashionslide (talk) 21:51, 17 April 2009 (UTC)
On the one hand, most languages compile down to either physical or VM machine code and C++ itself used to be a front end that was was translated into C, yet not many pages (any?) on Wikipedia display this translated form. On the other, "not having to write in GLib C" is a feature of Vala, hence maybe it is useful to show an example of the C code. In the end however the latter can simply be stated, and for consistency with other languages pages on Wikipedia, removing the generated code example seems like a good idea. mjog (talk) 03:36, 21 October 2016 (UTC)
How is it memory managed if not garbage collected? Does the clause "The primary advantage of Vala over C++/gtkmm is that Vala is memory-managed (not using garbage collection)." mean that it is reference counted, which is sometimes explained as garbage collection, sometimes not. C++ is not garbage collected, and memory management is crude, but then is Vala better?
I should say that one possible advantage of Vala could be that it is not C, nor C++. C++ has deep trouble in the specification, giving the significant deficiencies:
C has much much less deficiencies, most of which are impractical inconveniences:
Said: Rursus ☻ 08:47, 30 June 2008 (UTC)
The current OS support reads as "Every platform with an ANSI C compiler, Vala generates C code" This seems a bit misleading since GObject isn't ported to every OS. It seems it should read something more like "Every platform with an ANSI C compiler that GObject supports. Vala generates C code that depends on GObject." Or since GObject is usually dependent on GLib, perhaps it should read GLib instead of GObject... Any comments on this? —Preceding unsigned comment added by 206.127.184.24 (talk) 08:02, 19 February 2009 (UTC)
What's the origin of the name "Vala"? I can think of several candidates... Arny (talk) 00:26, 2 April 2012 (UTC)
I'm sorry for such drastic petition, but a programming language is characterized mainly by it's syntax and semantics.
Not by examples of how to code the classic Hello World! in different styles.
The object oriented example is very ill constructed,
the line:
stdout.printf("hello world!\n");
means that stdout
, which is an instance of the streams class, which is capable to process the printf("hello world!\n")
message.
It is too artificial to embed it in a class called sample, as was done in the article.
I came to this article trying to understand a free software source which includes modules with the .vala extension. But this article says no substantial thing about such language. What is it's advantage compared with plain C or C++, if I only see some complicated examples.
The article could start with an informal, or should I said semi-formal description of Vala syntax, maybe comparing it with C and C++. From which it seems to be inspired.
Then the formal syntax rules of the language (in BNF or similar) or at least a pointer to the official definition.
Then give some important semantic features, like differences in meaning of statements with the same syntax in C or C++ and Vala. I do not expect a formal (operational) semantics, for vala, as the vast of those new languages are not developed on such formal basis, but as variants or little improvements of other languages, like C/C++.
Neither I do expect from it to include all the semantics of the language in an encyclopedia article, but some important features at least. The present article mentions the capability to write anonymous functions, which seems interesting. I may be developed saying for example:
Why is important to have anonymous functions? How are they written? Are they really useful? I can define them, but can I generate them? In plain ANSI C one can use function pointers, but one can not create functions on the fly, (technically speaking: it is not a higher order language). There are some forms to overload functions, and that is why it is an interesting feature. Of course overloading methods is more natural in OO languages like C++. Can you say something like that in the Vala article?
How about recursion, iteration oriented languages, are not good to implement recursive functions, because as part of semantics, each time a function is called information to return is stored in a stack (see about the heap) which may be too small to be useful in practice. But self calling functions can be transformed in several ways to avoid such problem. Can you say something about this issue in Vala?
I hope that I have been clear with the idea of how an article like this about a programming language Vala, may be structured. — Preceding unsigned comment added by 189.178.72.176 (talk) 02:54, 12 October 2015 (UTC)
—wi24rd leave a comment 17:32, 13 February 2019 (UTC)
The current Vala versions are 0.46.9 (Stable) and 0.48.5 (LTS), both released on April 23, 2020. How can the infobox indicate there is a long-term support release? Kiamlaluno (talk) 11:57, 23 April 2020 (UTC)