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Python-to-C++ Compiler
Mark Dufour writes "Shed Skin is an experimental Python-to-C++ compiler. It accepts pure, but implicitly statically typed, Python programs, and generates optimized C++ code. This means that, in combination with a C++ compiler, it allows for translation of pure Python programs into highly efficient machine language. For a set of 16 non-trivial test programs, measurements show a typical speedup of 2-40 over Psyco, about 12 on average, and 2-220 over CPython, about 45 on average. Shed Skin also outputs annotated source code."
Until he addresses mixed types in n-tuples, this won't be useful for very many people.
"Who is the Journal of Quantum Physics going to believe?" --Stephen Hawking
This is a good step to make Python run a bit faster, but I don't think it'll really make a huge difference.
The best way to get some speed and still keep the nice Python functions and layout is just to export the most heavily used functions to native code (C/C++).
I don't know if its possible to take the C++ output and optimize it seperatly, that way you will have a good start to make native code though.
In short: Better, fast and easy, but not the best (if you can write native code)
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I think you're not supposed to read it. You're only supposed to feed it to your C++ compiler. f2c produced unreadable output too, but nobody read the output; at one time it was the only free fortran option on linux.
Among python programmers, I'm curious - how many use psyco (another python performance enhancement tool) for their projects? I fiddled with it a while ago (it didn't work because of a C module that it didn't like), but never had a compelling reason to go back to it. Performance optimization has never been important enough for my applications to merit the effort.
It's not wasting time, I'm educating myself.
I will have to explore it more, but it will be intriguing to see how they handle things like pointers and structs that are not in python.
Uh, why would they have to? This goes from Python to C++, not vice versa. If there are no pointers or structs in the Python code, why would they have to handle them? Certainly, it's quite possible that some Python variable types will be converted to pointers or structs in the output code, but that's orthagonal to the issue of Python not having them natively.
If you were trying to go from C++ to Python, then you'd have to convert C++ pointers and structs to some sort of Python data type, and your comment would make sense. As it is, I'm not sure what you were trying to say.
"The legitimate powers of government extend only to such acts as are injurious to others." Thomas Jefferson.
I don't see your point. Some of us use python. It takes me a fraction the time to do something in python than to do it in any other language. I'm not interested in writing native C++ code because it's hypothetically faster (it's not faster if I count coding time). But I am interested in a good python-to-C++ translator. Why wouldn't any python user be?
bzerodi's point, made with Zen-like simplicity, is that language choice should be made to minimize programmer time, not machine time. I am at least a factor of ten more productive with Python than with C or C++. I am also far more confident in the correctness of what I write per line of Python than with what I write per line of C/C++.
Yes, I have have wasted some time staring at the shell waiting and waiting for it to return from some complicated Python routine. I know that compiled C would faster, and hand-rolled assembler would be faster still. But I say to myself: hey, I wrote this code in a single afternoon, how many weeks of hair-pulling would it take to re-engineer this - and make it bug-free - in C? When I put it that way, I don't mind waiting the extra minutes for Python to do my dirty work.
As a previous poster mentioned, the ability to handle tuples of mixed-types is critical. I look forward to seeing great things from Shed Skin in the future.
Dictionaries are for loosers.
surely the best way to speed it up is to compile it straight to object code... c++ has to be compiled and just adds an intermediate step which will make things harder to debug...
Donald 'Duck' Dunn: We had a band powerful enough to turn goat piss into gasoline.
no, I'd be far more interested in a good compiler to compile that python straight to machine code...
Donald 'Duck' Dunn: We had a band powerful enough to turn goat piss into gasoline.
After four hours of tweaking, our expert C++ programmer was finally able to write something that beat our ten lines of Python code that took under five minutes to write. And it didn't beat it by much, whereas the first pass at a C++ version was an order of magnitude slower.
Which is why languages like python were written in the first place. They pretty much just make the underlying C calls anyways, but do so in a way that handles buffer overflows, pointers, etc., that pretty much make C/C++ so troublesome, hazardous, and hard to learn. I like java (alot really), but nothing beats a good scirpting language, like perl or python, to handle tasks like text manipulation. Python is especially good at using libraries, such as the imaging library, which are written in C anyways. How much faster can you get calling a C library from C than from python? I honestly don't know, but I can't imagine it's that much more. But when you add in speed of development, safety, and even portability, it's powerful.
Python's OOP is also a feature that makes it far more attractive than perl for me. Perl does OOP, but it's not as clean as python's, and I don't think it supports all the OOP features either. Doing GUI's is not the strength of any scripting language, but it depends on what you need to do. You can write a native frontend and embed python into a C or even a java application.
My problem? I was perfectly gruntled, until some numbnuts came by and dissed me.
Why? Read the linked page? Says it all. Violates most any Python code of any complexity out there. So if it doesn't convert Python code from the real world, what is it for? Making Python coders learn enough about C++ to remember the limitations and write/rewrite Python code to use it?
What the Python C/C++ interested people REALLY need is a book written by a group of Python AND C/C++ masters which teaches the two simultaneously showing complimentary methods of doing any given thing working from beginner to advanced and I DON'T mean "How to turn your n00b Python code into C/C++ hotness" sort of viewpoint. I mean both taught simultaneously in synch showing how they can interchange and compliment.
Software tricks for converting? Ultimately worse than not having them because it leads to horrible obfuscation because we don't know exactly what is going on when 13,412 lines of Python is turned into C++ because WE DIDN'T WRITE IT AND WE NEVER LEARNED C/C++. "Say Mike, that's great but you're the company code cowboy and you don't do C++ natively and I sure as hell don't read it being management so exactly what happens if this needs to be fixed? We've gone from importing open source code you couldn't read to writing our own open source code you can't read."
If my grammar and spelling are off, I am [distracted/tired/careless] (take your pick)
I love Python, but I hate the dynamic typing. It can be handy at times, but 99% of the time you make a variable to hold one kind of thing. Having the static typing would both improve performance (because the interpreter knew what you were up to) but would also eliminate bugs (because it would complain when I tried to set a double to "And now press...").
I'd love to see Python get optional static typing.
Comment forecast: Bits of genius surrounded by a sea of mediocrity.
It is worth mentioning that one of the the original implementations of C++ (if not the very first) was "cfront", a C++-to-C converter. I see this as a much easier way to get a new language implemented quickly, as you can take advantage of the common functionalities already implemented in the target language of the converter. Although Python is not a new language, using it as a compiled language is new, and thus I believe it is comparable to being a new language for this argument. C++ and Python have a lot in common, which makes C++ a very suitable target language for a Python-to-[compiled_language] converter.
If this converter proves to be successful, I believe that a GCC frontend will be written eventually. There are probably potential optimizations that would be difficult or impossible to implement any other way.
Some may think that the dynamic nature of Python may preclude its inclusion in GCC. Technically, all that would need to be done is to have a runtime to handle dynamic things, similar to how Objective-C (for which there is GCC support) has a runtime to handle message passing and late binding. However, a large portion of the potential efficiency of a compiled version of the language would be lost to these dynamic capabilities; luckily, a compiler can detect when things are implicitly static (in fact, this converter is limited to implicitly static constructs), and optimise them to be truly static at compile-time.
As another poster already said, file I/O is a bottleneck regardless of ANY language. So, try something different. Real-time h264 decoding for example.
This sig does not contain any SCO code.
...and that's why it shouldn't be a Python to C++ translator; it should be a GCC frontend instead (i.e., translating to GCC's internal representation).
"[Regarding the 'cloud,'] ownership was what made America different than Russia." -- Woz
Python is a terrific prototyping language (and lots of other things besides.) As a C++ coder I've been using it for prototyping stuff that will eventually be integrated into a larger application and therefore MUST be translated to C++. So what I'd like to see is a tool (written in Perl, just for the fun of having a linguistic threesome) that just does a light gloss on Python syntax to get me most of the way to human-readable C++. That would be far more useful (to me) than thsi thing, which sounds more like f2c, whose output could case brain damage in humans and cancer in rats, or possibly the other way around.
Blasphemy is a human right. Blasphemophobia kills.
Yeah, whenever I look at the output of my optimising compiler, it's really hard to understand too. It's all in assembler, for a start.
Plus, the quality of C code generated by CFront was rubbish - unreadable.
Same with the Modula-3 compiler I tried. You couldn't work out what was going on in the resulting C code without a load of work.
Can you see where I'm going with this?
"boo", a .NET language, allows dynamic typing by specifying 'duck' type. It achieves near-c# speed because all other data are statically typed.
.NET world.
It's a great language -- combining the benefits of Python, Ruby, and C# -- and it's wonderful for proto-typing in the