Game Library with Support for RPython - python

Are there any Python game libraries (Pygame, Pyglet, etc.) with support for RPython? Or game libraries specifically made for RPython? Or bindings for a game library for RPython?

Yes, check out the gameboy interpreter written in RPython, pygirl. https://bitbucket.org/pypy/lang-gameboy

RPython is not Python. They are different languages even though it just so happens that you can execute RPython code with a Python interpreter and get similar effects (much more slowly) to running the compiled RPython program. It is extremely unlikely for there to ever be any reasonable Python library (game library or any other kind) that also works in RPython. It would have to be specifically written for RPython, and if it worked in RPython it would be so inflexible when considered as a regular Python library that nobody would use it in that context.
If you want to program in a lower level compiled language with game libraries, use C# or Java. RPython is not a good competitor (in large part because it has very few libraries for anything, not even much of a standard library).
If you want to program in Python, use Python (possibly use the PyPy implementation of Python, which can be faster than the standard Python interpreter if it supports all the libraries you're using). RPython will not help you write Python code that goes faster.
If your goal is not to specifically produce a game, but rather to do some project in RPython because you want to learn RPython specifically, then that's a perfectly reasonable aim. But writing a game in will probably not be the most helpful project for learning to write RPython; you should probably consider writing some sort of interpreter instead, since that's what RPython is designed to do.

Related

Is Python byte-code, interpreter independent?

This is an obvious question, that I haven't been able to find a concrete answer to.
Is the Python Byte-Code and Python Code itself interpreter independent,
Meaning by this, that If I take a CPython, PyPy, Jython, IronPython, Skulpt, etc, Interpreter, and I attempt to run, the same piece of code in python or bytecode, will it run correctly? (provided that they implement the same language version, and use modules strictly written in Python or standard modules)
If so, is there is a benchmark, or place where I can compare performance comparison from many interpreters?
I've been playing for a while with CPython, and now I want to explore new interpreters.
And also a side question, What are the uses for the others implementations of python?
Skulpt I get it, browsers, but the rest? Is there a specific industry or application that requires a different interpreter (which)?
From https://docs.python.org/3/library/dis.html#module-dis
Bytecode is an implementation detail of the CPython interpreter. No
guarantees are made that bytecode will not be added, removed, or
changed between versions of Python. Use of this module should not be
considered to work across Python VMs or Python releases.
On the other hand, Jython "consists of a compiler to compile Python source code down to Java bytecodes which can run directly on a JVM" and IronPython compiles to CIL to run on the .NET VM.
The purpose is to better integrate into your programming environment. CPython allows you to write C extensions, but this is not necessarily true of other implementations. Jython allows you to interact with Java code. I'm sure similar is true of IronPython.
If so, is there is a benchmark, or place where I can compare
performance comparison from many interpreters?
speed.pypy.org compares pypy to cpython

When using the Python Interpreter, is the compiler used at all?

In Google's Python Class it reads
Python is a dynamic, interpreted (bytecode-compiled) language
I know what an interpreter is and know what bytecode is but the two together seem not to fit. After doing some reading it became a bit clearer that basically Python source code is automatically compiled before it is interpreted; but some new questions emerged.
When using the Python Interpreter does no compilation happen? If it does, when? For example if you're just typing code at the command line and it gets run each time you hit enter, when does a compiler have the opportunity to do its work?
Also in the linked to question above, #delnan gives a pretty broad definition of a compiler
A compiler is, more generally, a program that converts a program in
one programming language into a program in another programming
language...JIT compilers compile to native machine code at runtime
I guess my question is: what's the difference between an interpreter and automatic compiler? To refine the question a bit, if Python is compiled, why not compile all the way to machine code (or assembly, since I know writing compilers that can produce pure machine code is difficult)?
Perhaps it is best to forget semantics and just try to learn what Cpython is actually doing. When you invoke the Cpython binary, it does a number of things. Generally speaking, you can expect it to translate the code you've written into a sequence of bytecode instructions. This is the "compiling" stage that people will sometimes reference for python code. These are a more compact and efficient way to tell the interpreter what to do than your hand-written code. Frequently, python will cache these files for reuse in .pyc files (only re-generating if the associated .py file is newer). You can think of python bytecode as the set of instructions that the python virtual machine can run -- In a lot of ways, it's not really all that different than what you get for Java. When people speak of compiled languages (e.g. C), the compiler's job is to translate your code into a set of instructions that will run directly on your computer's hardware. Languages like Cpython and Java have an extra level of indirection (e.g. the Virtual Machine). The Virtual Machine runs directly on the computer's hardware and is responsible for interpreting the domain specific language.
Compared to standard "compiled" languages (e.g. C, Fortran), this stage is really light-weight -- and python doesn't do a lot of the checking that "traditional" compilers will do (e.g. typechecking). It pretty much only checks the syntax and does a few very simple optimizations using the peephole optimizer.

Calling Python from Ruby - PyPy compatibility

I'm looking to call Python code from Ruby. There are a few existing tools to do this and a few questions on this site recommending http://rubypython.rubyforge.org/, which works by embedding the Python interpreter in Ruby. I'm working on an app that uses libraries unique to Python (namely graph-tool, which I have reasons for using over, say RGL), but the final project is in Rails so having Ruby code do the controlling work would be ideal. I want it to be speedy so I'm using PyPy. Is there a way to get the PyPy interpreter embedded in Ruby code, or to make the Python interpreter in rubypython run PyPy?
No. Well, not without a lot of work.
First, RubyPython doesn't really include an embedded Python interpreter; it just wraps the interpreter at runtime. As shown in the docs, you can run it with any Python you want, e.g.:
>> RubyPython.start(:python_exe => "python2.6")
So, what happens when you try?
>> RubyPython.start(:python_exe => "/usr/local/bin/pypy")
RubyPython::InvalidInterpreter: An invalid interpreter was specified.
from /Library/Ruby/Gems/1.8/gems/rubypython-0.6.3/lib/rubypython.rb:67:in `start'
from /Library/Ruby/Gems/1.8/gems/rubypython-0.6.3/lib/rubypython/python.rb:10:in `synchronize'
from /Library/Ruby/Gems/1.8/gems/rubypython-0.6.3/lib/rubypython/python.rb:10:in `synchronize'
from /Library/Ruby/Gems/1.8/gems/rubypython-0.6.3/lib/rubypython.rb:54:in `start'
from (irb):4
Unfortunately, it requires CPython 2.4-2.7. It doesn't work with CPython 3.x, PyPy, Jython, etc. Again, from the docs:
RubyPython has been tested with the C-based Python interpreter (cpython), versions 2.4 through 2.7. Work is planned to enable Python 3 support, but has not yet been started. If you’re interested in helping us enable Python 3 support, please let us know.
Without looking at the code, I'm guessing rubypython is using rubyffi to either:
* Wrap the CPython embedding APIs, or
* Directly call CPython VM internals via its dll/so/dylib exports.
If it's the former, the project might be doable, but still a lot of work. PyPy doesn't support CPython's embedding APIs. If it had its own embedded APIs, you could potentially rewrite rubypython's lower level to wrap those instead, and leave the higher-level code alone. But embedding PyPy at all is still a work in progress, (See http://mail.python.org/pipermail/pypy-dev/2012-March/009661.html for the state of affairs 6 months ago.) So, you'd need to first help get PyPy embedding ready for prime time and stable, and then port the lower level of rubypython to use the different APIs.
If it's the latter, you're pretty much SOL. PyPy will never support the CPython internals, and much of what's internal for CPython is actually written in RPython or Python and then compiled for PyPy, so it's not even possible in principle. You'd have to drastically rewrite all of rubypython to find some way to make it work, instead of just porting the lower level.
One alternative is to port Ruby to RPython and use PyPy to build a Ruby interpreter and a Python interpreter that can talk to each other at a higher level; then, writing something like rubypython for PyRuby and PyPy would be trivial. But that first step is a doozy.

Use Cython as Python to C Converter

I have huge Python modules(+8000 lines) .They basically have tons of functions for interacting with a hardware platform via serial port by reading and writing to hardware registers.
They are not numerical algorithms. So application is just reading/writing to hardware registers/memory. I use these libraries to write custom scripts. Eventually, I need to move all these stuff to be run in an embedded processor on my hardware to have finer control, then I just kick off the event from PC and the rest is in hardware.
So I need to convert them to C.If I can have my scripts be converted to C by an automatic tool, that would save me a huge time. This is why I got attracted to Cython. Efficiency is not important my codes are not number crunchers. But generated code should be relatively small to fit in my limited memory (few hundreds of Kilobytes).
Can I use Cython as converter for my custom Python scripts to C? My guess is yes, in which case can I use these .c files to be run in my hardware? My guess is not since I have to have Cython in my hardware as well for them to run. But if just creates some .c files, I can go through and make it standalone since code is not using much of features of Python it just use it as a fast to implement script.
Yes, at its core this is what Cython does. But ...
You don't need Cython, however, you do need libpython. You may feel like it doesn't use that many Python features, but I think if you try this you'll find it's not true -- you won't be able to separate your program from its dependence on libpython while still using the Python language.
Another option is PyPy, specifically it's translation toolchain, NOT the PyPy Python interpreter. It lets you translate RPython, a subset of the Python language, into C. If you really aren't using many Python language features or libraries, this may work.
PyPy is mostly known as an alternative Python implementation, but it is also a set of tools for compiling dynamic languages into various forms. This is what allows the PyPy implementation of Python, written in (R)Python, to be compiled to machine code.
If C++ is available, Nuitka is a Python to C++ compiler that works for regular Python, not just RPython (which is what shedskin and PyPy use).
If C++ is available for that embedded platform, there is shed skin, it converts python into c++.

Developing PyPy's Rpython as a general programming language [closed]

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Is there any interest in developing Rpython (Restricted Python) from the PyPy project as a general purpose programming language? Perhaps it could be a fork from the PyPy project. Does such a project exist? Since the programs are compiled, one could simply contribute modules written in Rpython, and it could compete with other python implementations including CPython and PyPy.
I can't speak for everyone else, but I personally am extremely interested in using RPython as a general-purpose language. To answer some other people's questions:
Why? Because Cython is a pain to figure out how to use. If you don't put in a lot of tricky type declarations just right, you don't get any speedup. With RPython, it will run fast or it won't run at all.
Using PyPy offers a good speedup, but currently not nearly as much as RPython.
RPython might be a good way to get super-fast, somewhat Pythonic code. Here's an example to help you get started. I'm not aware of any large projects to do this, unfortunately.
Yes, there is already a project to use the translation tool chain of PyPy to create standalone executables and libraries using RPython. It is called RPythonic.
A general purpose RPython would not be a competitor for CPython and PyPy. It wouldn't even be a competitor for things like Cython.
Why? Because RPython is not Python!! RPython is merely a language which shares some syntax with Python; enough that a Python interpreter can execute RPython code, but you cannot take Python code and compile it as RPython.
The restrictions on Python that are added to enable RPython to be statically typed and compiled (indeed, to have static type inference) are so severe that they completely change the language. If you want to write an RPython program, you have to decide to do so up front and write it in RPython. You can't write a program in Python and then decide to compile it as RPython, and you can't even tweak a realistic Python program a bit to make it RPython. Normal Python code is nothing like normal RPython code; writing RPython is more similar to writing Java or C#.
So if you want to write general programs in Python but you want them to go faster, RPython has very little to offer you. That's the niche PyPy's Python interpreter is trying to fill.
If you want to write general programs in a lower level compiled language because you need your program to run faster than Python, then there are existing very mature languages and libraries for that, like Java or C#.
The reason to code in RPython would be to do something that is particularly made better by RPython. Like writing interpreters to which you can add garbage collectors and JIT compilers without having to write them by hand! Here RPython shines, and yes I would be very interested in a more polished and usable RPython interpreter-writing environment. But as a general purpose programming language for writing programs that don't particularly benefit from RPython's specialities, it would simply be a monstrous amount of work to get it to the point where it could compete with existing languages that already fill that role better. It barely even has a standard library now (because almost none of Python's extensive standard library is usable in RPython), for example.
From the looks of it, the restrictions are quite severe and on the whole it's a lot less to program in, I imagine. That's necessary for implementing PyPy, but generally if you want fast compiled code that can interact with Python, you'd use Cython (which is targeted at CPython extensions and supports pretty much all of Python seamlessly) or write code in one of the more common languages that can do this. And if you just want fast, compiled code... well, RPython may be more pleasant than e.g. C, but still, I don't see a significant advantage here (at least none that would warrant the effort to create a usable, stable language).
Why would I want to write directly in RPython?
It seems so much simpler to Python code and run PyPy.
Why would I want to write C code?
It seems so much simpler to write Python and have PyPy be implemented in C
Why would I want to write assembler code?
It seems so much simpler to write Python and have PyPy implemented in C and C implemented in Assembler.
I guess it really is turtles all the way down.
Why would I want to stop using the most convenient language and switch to a less convenient language?
What's the value in giving up a nice language?

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