Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.python > #16378 > unrolled thread

Executing .pyc using python c api

Back to article view | Back to comp.lang.python

Contents

  Executing .pyc using python c api Mrinalini Kulkarni <mrinalini@edss.co.in> - 2011-11-29 13:04 +0530
    Re: Executing .pyc using python c api Ulrich Eckhardt <ulrich.eckhardt@dominolaser.com> - 2011-11-29 10:02 +0100
      Re: Executing .pyc using python c api 88888 Dihedral <dihedral88888@googlemail.com> - 2011-11-29 06:19 -0800

#16378 — Executing .pyc using python c api

 Hi

 I need to run .pyc files using python c api. if i do PyImport_Import it 
 executes the script. However, i need to pass a set of variables and 
 their values which will be accessed from within the script. How can this 
 be done.

 thanks,

[toc] | [next] | [standalone]

#16384

Am 29.11.2011 08:34, schrieb Mrinalini Kulkarni:
> I need to run .pyc files using python c api. if i do PyImport_Import it
> executes the script. However, i need to pass a set of variables and
> their values which will be accessed from within the script. How can this
> be done.

I don't think what you want is possible, due to a think-o in your 
design. Let me explain...
Firstly, .pyc files are basically the same as .py files, only in a 
different presentation. Then, PyImport_Import is basically the same as 
using "import" in a Python program. Now, and that is where your fault 
lies, importing a module actually means executing that module! For 
example, the definition of a function is code that when executed will 
cause a function to be created and attached to the current scope with 
the according name. This is what makes it so easy to implement local 
functions that are parametrized by arguments to the outer function. 
Still, a function is not something that is "static", like in C or Java, 
but rather the result of executing its function definition.

Now, how to get around this? The specialty about the import is that the 
__name__ attribute is not set to "__main__", upon which many scripts 
already react. So, in order to "prevent execution" (in the sense that 
you probably mean), you simply wrap the according code in a function. 
The function definition will then be executed, giving you a function 
that you can call with the according parameters, but the function itself 
will not be executed automatically. If you want that to happen when 
executing the .pyc file directly, check the content of __name__ and call 
the function if it is "__main__".

Note that another approach would be introspection, traversing through 
the namespaces to find out those parameters, but I would consider this 
solution as hackish if the one above is feasible.

Good luck!

Uli

[toc] | [prev] | [next] | [standalone]

#16393

On Tuesday, November 29, 2011 5:02:31 PM UTC+8, Ulrich Eckhardt wrote:
> Am 29.11.2011 08:34, schrieb Mrinalini Kulkarni:
> > I need to run .pyc files using python c api. if i do PyImport_Import it
> > executes the script. However, i need to pass a set of variables and
> > their values which will be accessed from within the script. How can this
> > be done.
> 
> I don't think what you want is possible, due to a think-o in your 
> design. Let me explain...
> Firstly, .pyc files are basically the same as .py files, only in a 
> different presentation. Then, PyImport_Import is basically the same as 
> using "import" in a Python program. Now, and that is where your fault 
> lies, importing a module actually means executing that module! For 
> example, the definition of a function is code that when executed will 
> cause a function to be created and attached to the current scope with 
> the according name. This is what makes it so easy to implement local 
> functions that are parametrized by arguments to the outer function. 
> Still, a function is not something that is "static", like in C or Java, 
> but rather the result of executing its function definition.
> 
> Now, how to get around this? The specialty about the import is that the 
> __name__ attribute is not set to "__main__", upon which many scripts 
> already react. So, in order to "prevent execution" (in the sense that 
> you probably mean), you simply wrap the according code in a function. 
> The function definition will then be executed, giving you a function 
> that you can call with the according parameters, but the function itself 
> will not be executed automatically. If you want that to happen when 
> executing the .pyc file directly, check the content of __name__ and call 
> the function if it is "__main__".
> 
> Note that another approach would be introspection, traversing through 
> the namespaces to find out those parameters, but I would consider this 
> solution as hackish if the one above is feasible.
> 
> Good luck!
> 
> Uli

Please use psyco and pyrex and C or whatever that can read saved results in a file, or just learn how to replace a hash or a sort in  python's build in library of better speed, don't do reference overheads in 
those c type variables that won't overflow and underflow  and used by other objects in python. Not trivial but well documented to cheer for a race!

 

[toc] | [prev] | [standalone]

Back to top | Article view | comp.lang.python

csiph-web