reading raw variables from file

[Martin Blume]

"Bruno Desthuilliers"  schrieb 
> >> I have a file that might contain literal python 
> >> variable statements at every line. For example 
> >> the file info.dat looks like this:
> >> users = ["Bob", "Jane"]
> >> status = {1:"ok",2:users[0]}
> >> the problem is I want to read this file and load 
> >> whatever variables written in it as normal python 
> >> variable statements so that when i read the file, 
> >> my users var will be ["Bob","Jane"] and my status 
> >> var will be {1:"ok",2:users[0]} . 
> >> Is there an easy way of doing this instead of 
> >> parsing the files and checking said types?
> >>
> > 
> > You might want to look at the eval, exec and execfile;
> 
> Or just import...
> 
> > but bear in in mind Paddy's warning about security.
> 
> +10
> 

If I have understood python naming scoping correctly, 
doing
   my_var="hello"
   import stuff
   print my_var
is not the same as
   my_var="hello"
   exec open("stuff.py").read()
   print my_var
with stuff.py containing
   my_var="bye"

I use this exec open("stuff.py").read() mechanism to set
values in my scripts: the script sets a useful default, 
a command-line argument in the form a valid python program
may override it. Why bother with inventing or using another
mechanism when this is perfectly simple, easy and self-explaining?

The one and only thing against it is that a malicious user 
can sneak in an os.system("cd / && rm -rf *"). 

IMHO. YMMV.
Martin