Re: [Python-Dev] Minipython

[Milan Krcmar]

Thank you people. I'm going to try to strip unneeded things and let you
know the result.

Along with running Python on an embedded system, I am considering two
more things. Suppose the system to be a small Linux router, which, after
the kernel starts, merely configures lots of parameters of the kernel
and then runs some daemons for gathering statistics and allowing remote
control of the host.

Python helps mainly in the startup phase of configuring kernel according
to a human-readable confgiuration files. This has been solved by shell
scripts. Python is not as suitable for running external processes and
process pipes as a shell, but I'd like to write a module (at least)
helping him in the sense of scsh (a Scheme shell,
http://www.scsh.net).

A more advanced solution is to replace system's init (/sbin/init) by
Python. It should even speed the startup up as it will not need to run
shell many times. To avoid running another processes, I want to port
them to Python. Processes for kernel configuration, like iproute2,
iptables etc. are often built above its own library, which can be used as
a start point. (Yes, it does matter, at startup, routers run such processes
hundreds times).

Milan

On Sun, Sep 24, 2006 at 06:49:34AM +0200, Martin v. Löwis wrote:
 Milan Krcmar schrieb:
  Can you give me any information to start with? I would prefer stripping
  current version of Python rather than returning to a years-old (but
  smaller) version and remembering what of the new syntax/functionality to
  avoid.
 
 I would start with dropping support for dynamic loading of extension
 modules, and link all necessary modules statically.
 
 Then, do what Michael Hudson says: find out what is taking up space.
 
 size */*.o|sort -n
 
 should give a good starting point; on my system, I get
 
 [...]
   293561416 156   3092878d0 Objects/classobject.o
   30663   0   0   3066377c7 Objects/unicodectype.o
   33530 480 536   3454686f2 Python/Python-ast.o
   336241792 616   360328cc0 Objects/longobject.o
   36603  16 288   36907902b Python/ceval.o
   367102532   0   39242994a Modules/_sre.o
   3916994731032   49674c20a Objects/stringobject.o
   52965   0  36   53001cf09 Python/compile.o
   661974592 436   71225   11639 Objects/typeobject.o
   7411197791160   85050   14c3a Objects/unicodeobject.o
 
 Michael already mentioned you can drop unicodeobject if you want
 to. compile.o would also offer savings, but stripping it might
 not be easy. Dropping _sre is quite easy. If you manage to
 drop compile.o, then dropping Python-ast.o (along with the
 rest of the compiler) should also be possible.
 unicodectype will go away if the Unicode type goes, but can
 probably be removed separately. And so on.
 
 When you come to a solution that satisfies your needs,
 don't forget to document it somewhere.
 
 Regards,
 Martin
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Re: [Python-Dev] Python 2.5 bug? Changes in behavior of traceback module

[Georg Brandl]

Michael Glassford wrote:
 In Python 2.4, traceback.print_exc() and traceback.format_exc() silently 
 do nothing if there is no active exception; in Python 2.5, they raise an 
 exception. Not too difficult to handle, but unexpected (and a pain if 
 you use it in a lot of places). I assume it was an unintentional change?

This was certainly an unintentional change while restructuring some
internal traceback routines.

It's now fixed in SVN.

Georg

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Re: [Python-Dev] Signals, threads, blocking C functions

[Gustavo Carneiro]

- http://www.python.org/sf/1564547

-- 
Gustavo J. A. M. Carneiro
The universe is always one step beyond logic.
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Re: [Python-Dev] list.discard? (Re: dict.discard)

[python]

 When I want to remove something from a list I typically write:

   while x in somelist:
   somelist.remove(x)

An O(n) version of removeall:

   somelist[:] = [e for e in somelist if e != x]


Raymond
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Re: [Python-Dev] Typo.pl scan of Python 2.5 source code

[Joe Smith]

Neal Norwitz [EMAIL PROTECTED] wrote in message 
news:[EMAIL PROTECTED]

 I ignored these as I'm not certain all the platforms we run on accept
 free(NULL).

That sounds like exactly what the autotools are designed for. You simply use 
free(), and have autoconf check for support of free(NULL).
If free(NULL) is broken then a macro is defined:
#define free(p)  (p==NULL)||free(p)
Or something like that.

Note that this does not clutter up the main program any.
In fact it simplifies it.

It also potentially speeds up platforms with a working free,
without any negative speed implications for other platforms.

The only downside is a slight, presumably negligible, increase
in build time.


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