I know Jython and JRuby is ported to JVM, and scala/Clojure is native to JVM, what about Groovy? Groovy looks like a dynamic language, I guess it is ported, but it seems it could also be compiled.
For those language native to JVM such as Scala, is that some tool to decompile the code to the source code?
"Ported" usually means "retargeted to run on." Groovy was designed to bring dynamic features from languages like Python and Smalltalk to Java. It was designed to be an extension of Java and in that sense it's native to the JVM and to the Java language. (The Groovy language, object model, and run-time libraries are extensions of Java's.)
But it sounds like you're asking about whether Groovy is interpreted or compiled. You can use groovyc to compile Groovy source code to Java .class files and run them in the JVM (linking in some Groovy run-time libraries). Or you can run Groovy source code interactively in GroovyShell, but what that does is compile, load, and run code for you incrementally.
A web search for [groovy decompiler] returns some possibilities for you.
I'm not sure whether it answers the entirety of your question, but the vast majority of Groovy and Groovy-Eclipse compiler is written in java, as seen on both projects' GitHub repositories.
Related
I'd like to build a DSL and use it as follows:
The DSL compiles to Java.
Export the DSL compiler and package it (i.e. as a JAR), so I can invoke the DSL compiler from a Java application to compile "code written in my DSL" into "Java source code" (I'll use other libraries to programmatically compile Java into bytecode).
Can I use JetBrains MPS to build a DSL and export its compiler as described? If no, other suggestions are appreciated?
I raised the question on MPS Support forum, and the answer I got was that it's not possible to export a compiler for my DSL (e.g. as JAR) from MPS IDE and then invoke the exported compiler from some Java application (think of a Java backend service) passing a text input representing a program written on my DSL.
Though you can use ant to invoke the "MPS code generator" (which is responsible for generating the target language code, e.g. Java, representing the input DSP program), but the generator expects as input "the MPS model" of your DSL program (I guess it's some AST like MPS internal representation of the DSL program). But the only way to generate "the MPS model" of your DSL program is by using Jetbrains' MPS IDE (or a stripped version of it, or intellij with a plugin for your DSL). In other words, the only way to write/edit programs in your DSL and be able to compile them, is by using Jetbrains MPS IDE (or one of its derivatives).
Link to the question I posted on MPS Support forum and the answer.
It seems to me your question is not so far from this documentation entry: https://confluence.jetbrains.com/display/MPSD32/Building+standalone+IDEs+for+your+languages
Maybe you cannot do it directly as a jar library, but it is possible, with some ant or gradle magic, to call a DSL compiler (or, as it's called in MPS, a generator) from an ant task. Documentation about this can be found at https://www.jetbrains.com/help/mps/building-mps-language-plugins.html#
I know it says building plugins but the same mechanism is used.
Why you would want to do this, though, eludes me, since the strong point of MPS is IDE support and very advanced multi-language integration, not necessarily code generation.
invoke the exported compiler [...] passing a text input representing a program written on my DSL
Your idea is sadly inherently flawed. There is no such thing as an MPS "DSL compiler" which takes text as input. In MPS there are generators which transform your DSL into another MPS language, in your case your target language would be BaseLanguage (MPS version of Java). After the transformation, the Java source code is generated as .java files and is automatically compiled as .class files. So yeah, this can be done with an Ant script built in BuildLanguage and called from cmd. But, the generator does NOT take as input text but an AST. The AST is your program "coded" (proper term would be modeled) in MPS.
So what you actually want is a parser (if your language is textual and parseable that is), which has text as input and AST as output. Once you have the AST in any form, you can somehow put it into an MPS model.
Please refer to my other answer where I commented on some portability (basically import, export) in MPS here. I have mentioned (not only) a project I am working on there. It allows to import a language and programs into MPS.
If you don't want to use MPS' IDE at all, but to work with text, it loses the advantage of MPS as a language workbench (LWB) with projectional editor. Maybe you should use another textual LWB (f.e. Xtext) or a parser generator (f.e. ANTLR). If the grammar definitions in parser generators scare you, you could use a model-based parser generator like YAJCo (I have contributed).
I have started to use Haxe to convert my ActionScript 3 projects into NME, but, I like to know please what is Neko in the world of Linux? I searched for it, I found its an animated cat!
Can any one please explain to me?
Neko for most people is nothing more than a Haxe target. That's not technically true (it does have its own language, and could potentially be a target for other languages), but for most people, Neko is one of the Haxe output targets.
In the same way the Java Virtual Machine (JVM) can be targeted from multiple languages (See the list on wikipedia), Neko is a bytecode format that can theoretically be written to from multiple languages. For Neko however, most people seem to use Haxe to create their *.n files.
For Haxe programmers, the Neko target lets you:
Write command line tools and utilities (for example, haxelib and haxedoc are written in Haxe targeting Neko)
Write web apps or dynamic web pages - using mod_neko (or mod_tora) you get a web processor with the same sort of capabilities as PHP, but a fair bit faster.
Create games with NME (which originally started with Neko, it stands for Neko Media Engine), and compile them quickly, having a target closer to what CPP has, but which compiles a lot faster and where the output is cross platform.
A runtime that is closely tied into Haxe and can be used from within macros etc - so you can use all of the neko.* classes inside Macros.
If you're only interested in targetting SWF or JS, you'll probably not have much need for Neko. But if you are writing server side code, you'll appreciate the performance, and if you are writing CPP, you may appreciate having a simple target that is dead easy and super quick to compile, and which behaves similarly to CPP.
Of course, outside of Haxe neko is it's own language... but to me at least it seems most people just use it with Haxe.
More Info:
If you want to write in the Neko language (See this tutorial) you might save your code as "myfile.neko" and compile with nekoc myfile.neko, which will compile a Neko bytecode file "myfile.n".
If you want to write in the Haxe language, you might save your file as "MyFile.hx" and compile with "haxe -neko myfile.n -main MyFile".
The "myfile.n" that is generated by both of these doesn't have human readable source code - this is the Neko bytecode. You can run it on any computer that has Neko installed by running neko myfile.n. You can turn it into an executable (that runs without Neko installed) for your platform/OS by running nekotools boot myfile.n.
Here is a tutorial on Getting Started With Neko, which covers both command line programs you write and (very very basic) web pages.
"Neko" is Japanese for "cat", which is probably why you found what you did.
Neko is also a virtual machine (a "VM") like the Java Virtual Machine ("JVM") or the .Net Common Language Runtime (".Net CLR").
Neko has a custom high-level language made as an easily targeted language backend (like C-- in a way, but not like LLVM, which is closer to an assembly language). In other words: It's something that a programming language can be translated into rather than a more involved "full" compilation (like to assembly, to bytecode, or to machine code). Neko's language can be translated into a bytecode, which is portable and is usually stored in a ".n" file.
Neko was made by Nicolas Cannasse (the same person that made the Haxe Programming language), which is probably why Haxe has a Neko target in its compiler, and the Haxe tools, such as "haxelib" use it. Because the tools are compiled into ".n" files, they only need to be built once, and then they work on any platform with the VM executable "neko" installed.
Perhaps a more interesting bit about neko, and why you should learn it for Haxe development is that it's the runtime used for compile-time macros. See this tutorial for how part of your program can be run at compile time with full access to the build machine, which means you could even do complex tasks, such as parse a data file, at compile time.
Neko provides a common runtime for several different languages, including javascript and haxe. the compiler converts a source file (.neko) into a bytecode file (.n) that can be executed with the virtual machine. you can use the compiler as standalone commandline executable separated from the virtual machine, or as a neko library to perform compile-and-run for interactive languages. neko was written by nicolas cannasse.
you can find Neko Tutorial here
i recently came to know that groovy++ have been released, what is the major difference is in Groovy and Groovy++?
From the groovy++ page http://code.google.com/p/groovypptest/
Groovy++ is statically typed extension of Groovy programming language. Additionally to all goodies of standard Groovy it adds a lot of functionality
compile time checking of code
as fast as Java performance of compiled code
easy mixing of statically and dynamically typed code
very powerful type inference
tail recursion traits (interfaces with default implementation)
extension methods (compile time categories)
standard library of utilities for functional programming, concurrency and distributed computing (early prototype stage)
There is a good article on what Groovy++ brings to Groovy here. It includes benchmark results, so you can see the performance difference vs. Groovy and straight Java.
Groovy++ is an extension to the core Groovy 1.x language. You drop the GroovyPP.jar file into the Groovy library directory, add #Typed in front of the package keyword in your code, then run your code just as you would in core Groovy. It infers the types, AND runs faster!
Can anyone point to programming language which has python-like syntax, but from the very beginning was designed to generate native code? I'm aware of Boo only, but it uses .net, not native code generation. Well, if nothing else than python-like languages which generate .net/java bytecode are fine too.
Cython might do -- the C code it generates is for Python extensions, but the whole thing can be packaged up and you'll be running native code throughout (after the 'import';-).
I must admit that I don't quite understand your question, for two reasons:
You are asking for a language with native code generation, but native code generation has nothing to do with the language, it is a trait of the implementation. Every language can have an implementation with native code generation. Several Python implementations have native code generation. There are C compilers that compile to JVM bytecode, CIL bytecode or even ECMAScript sourcecode. There are even C interpreters. There are also compilers that compile Java sourcecode or JVM bytecode to native code.
Why do you care about the syntax? It is probably the least important factor about choosing a programming language.
Anyway, Nim is a programming language which has an implementation which supports native code generation (or more precisely an implementation which supports C source code generation) and whose syntax is a hybrid between Wirthian style (by the looks of it the most important influences are Oberon and Delphi) and Python.
However, the fact that it has Pythonic syntax isn't going to help you at all if you don't like European style language design or Wirthian style OOP.
Also found today Delight applying Python syntax on a D back-end.
And Converge too.
Check out Cobra
It is strongly influenced by Python, C#, Eiffel, Objective-C and other programming languages. It supports both static and dynamic typing. It has first class support for unit tests and contracts. Cobra provides both rapid development and performance in the same language.
shedskin compiles Python to C++
From shedskin project page
Shed Skin is an experimental compiler,
that can translate pure, but
implicitly statically typed Python
programs into optimized C++. It can
generate stand-alone programs or
extension modules that can be imported
and used in larger Python programs.
Genie which is part of the gnome project: http://live.gnome.org/Genie
I think it's exactly what you're looking for.
If you are happy with something that compiles down to Java bytecode you could have a look at Jython. Quoting from their FAQ:
JPython is an implementation of the Python programming language which is designed to run on the Java(tm) Platform. It consists of a compiler to compile Python source code down to Java bytecodes which can run directly on a JVM, a set of support libraries which are used by the compiled Java bytecodes, and extra support to make it trivial to use Java packages from within JPython.
I've not actually used it yet but am considering it on some projects where I have to integrate with existing an Java codebase.
HTH
PyPy is a project to re-implement Python in Python. One of it's goals is to allow the use of multiple back-ends, including C. So you can take a pure Python program, convert it to C and compile it to native code. It is still a work in progress, so probably not suitable for production code.
You can find all of the previously mentioned languages, plus some more, here: http://wiki.python.org/moin/PythonImplementations
Nim is a statically typed compiled systems programming language. It combines successful concepts from mature languages like Python, Ada and Modula.
https://nim-lang.org/
You can also investigate IronPython - a python inplementation on the .NET framework
You can try Genie. It's the same like Vala, but with Python-like syntax. If you want to develop apps for Linux with GTK, and you want to compile it to native app, Vala or Genie is really good choice.
Why would I choose to use Groovy when I could use Jython or Jruby? Does the language provide any inherent advantages to make up for the fact that Jython and Jruby skills are applicable to their parent languages outside of the JVM?
Keep in mind that I purposely keeping this question generic, but if there are any advantages that exist in a particular domain, please don't hesitate to describe them.
EDIT
To clarify, If I write some code in Jruby, I can now, in some cases, move that code outside of the JVM if need be, or at the very least I have gained a better understanding of Ruby. Whereas Groovy skills are applicable only when using a language that just exists inside the JVM. Jython and Jruby have this built in advantage, what does Groovy have to make up for this disadvantage?
If Groovy doesn't have any advantages that you've found, and you would suggest just using Jython or Jruby, let me know.
Edit 2
Thanks everyone for all the answers, most of them make the same point, Groovy integrates slightly better with Java then Jython or Jruby.
Follow up
Using Netbeans 6.5 as my IDE I have found that Groovy to integrates better with Java projects then Jruby. I am not sure if lack of integration is a failing of Jruby or Netbeans. But after using it for alittle Groovy definitely seems to have a leg up.
I've done pretty extensive development in Ruby and Groovy (as well as a little Jython using Grinder as a load testing tool).
Of the 3, I prefer Groovy the most. I like the closure syntax the best and I think that it has the tightest integration in how it works with other java classes on the JVM. It's been a little while since I last used JRuby, but importing Java classes and working with the classloader in JRuby didn't feel as clean to me.
The fact that Groovy is also essentially a superset of Java means that the huge population of Java programmers out there will have a quicker uptake time in picking Groovy up over Ruby/JRuby. They can start programming it like it's Java and slowly start inserting idomatic groovy as they pick it up.
More to the point of what you're asking, I think that another advantage of Groovy is that the language that you go to when you want to optimize something is almost the exact same syntax, it's Java. If you're working in the Ruby or Python worlds, you're going to have to go to either C which is a big shift or Java, which is also quite different than those languages. Programming in Groovy tends to help keep your Java skills somewhat sharp as well.
If you have particular access to a Ruby or Python infrastructure, or a team that has familiarity with those kind of environments, then I could see choosing one of those other languages.
Really, all 3 of them are very nice languages and what you pick should depend more on the problem that you're trying to fix and the resources that you have available to you. Once you've become proficient in one dynamic language, picking up a second or a third is much easier.
I would say if you need to mix Java with Jruby/Groovy, go with Groovy. As everybody said, Groovy has tighter Java integration.
But as far as the language implementation goes, I prefer the Ruby language over Groovy, the language revolves around itself, in Groovy there are some hacks that are inherent to the implementation itself (just watch a Grails stacktrace vs. a Rails stacktrace and you'll see what I mean).
I highly recommend seeing Neal Ford's comparison of Groovy and JRuby
I think Dick Wall gave a very good summary of the differences between these three on the Java Posse podcast (#213, about 34:20 in) ...
"JRuby was designed to make programmers happy ... it's a programming language developer's choice; Python has very strong roots in simplicity and education; Groovy is aimed squarely at being the choice for Java developers ... it's a very familiar environment for Java ... with support for annotations".
In terms of moving the language outside of the JVM, I don't think the Java runtime imposes much of an overhead -- it's a simple install, and you need to set some environment variables -- but it does provide a number of benefits including a mature runtime which has been highly optimised, and a large set of libraries. The JRuby team are now reporting better performance than the native MRI. http://blog.headius.com/2008/08/twas-brillig.html
I've only had experience with Jython and Groovy. The biggest disadvantage with Jython, at the moment, is that the latest release recommended for production (2.2.1) has a feature set that "roughly corresponds to that of Python-2.2" (Jython FAQ). There is a beta implementing what I assume is Python 2.5, which is now a version behind. Don't know if the same can be said for JRuby.
I don't know why you should choose Groovy because I don't know your background. If you are a Java developer Groovy feels more similar to your current language then JRuby or Jython. Groovy combines the best of Java, the language, Java, the platform, and Ruby the language.