[Tutor] a quick Q: how to use for loop to read a series of files with .doc end

[Steven D'Aprano]

Walter Prins wrote:

> As for the compiler/interpreter argument, I'll just point out again that
> actually Python in its various forms can either be compiled and/or
> interepreted, it depends on you really.  For compiled Python flavours, see
> for example Cython (http://cython.org/) which provides a way to write C/C++
> modules for Python effectively in Python syntax.  (Cython arguably also
> makes the "need to write wrapper" comment a moot point.)   

Cython is not Python. It is a separate language similar to Python, based 
on Python, but not actually Python. It's actually a superset of Python. 
Any Python code should be legal in Cython, but not all Cython code is 
legal in Python.

See, for example:

http://docs.cython.org/src/userguide/tutorial.html#primes

and notice that the Cython code:


def primes(int kmax):
     cdef int n, k, i
     cdef int p[1000]
     # ...

gives you a SyntaxError in Python.

Credit where credit is due: Cython is a wonderful tool and very useful 
to anyone wanting to write C extensions for Python, but it isn't Python. 
That's not a limitation or a bad thing: it couldn't do what it sets out 
to do if it were Python.


> Or see Shedskin (
> http://shed-skin.blogspot.com/), a Python to C++ static compiler), 


Shedskin, on the other hand, is a subset of Python: it can only work 
with a restricted set of Python features. So also not Python.

http://code.google.com/p/shedskin/

But still a very useful and valuable tool.


> or Psyco
> (http://psyco.sourceforge.net/introduction.html ), a JIT (Just In Time)
> compiler for CPython.  

Psyco, on the other hand, is an add-on to Python: it runs inside the 
CPython compiler, as an importable module, rather than being a separate 
Python interpreter.


> Or see Pypy (http://pypy.org/) which is another
> reimplementation of the Python language with an optimizing JIT compiler.
> (The following post re realtime image processing in Python is rather
> impressive:
> http://morepypy.blogspot.com/2011/07/realtime-image-processing-in-python.html)


PyPy is very impressive, and it truly is an independent implementation 
of Python, like CPython, Jython, IronPython and Stackless. It is faster 
than CPython (although requires more memory) and in certain restricted 
micro-benchmarks faster than C.

Yes, faster than C.

http://morepypy.blogspot.com/2008/01/rpython-can-be-faster-than-c.html
http://morepypy.blogspot.com/2011/02/pypy-faster-than-c-on-carefully-crafted.html
http://morepypy.blogspot.com/2011/08/pypy-is-faster-than-c-again-string.html



This just goes to show that *languages* aren't faster or slower than 
other languages. Languages just are. But *implementations* can be faster 
or slower.



-- 
Steven