Adding to a module's __dict__?

Dave Angel davea at ieee.org
Tue Mar 2 22:23:34 CET 2010


Terry Reedy wrote:
> On 3/2/2010 11:18 AM, John Posner wrote:
>> On 3/2/2010 10:19 AM, Roy Smith wrote:
>>>
>>> Somewhat sadly, in my case, I can't even machine process the header
>>> file. I don't, strictly speaking, have a header file. What I have is
>>> a PDF which documents what's in the header file, and I'm manually re-
>>> typing the data out of that. Sigh.
>
> There are Python modules to read/write pdf.
>
>> Here's an idea, perhaps too obvious, to minimize your keystrokes:
>>
>> 1. Create a text file with the essential data:
>>
>> XYZ_FOO 0 The foo property
>> XYZ_BAR 1 The bar property
>> XYZ_BAZ 2 reserved for future use
>>
>> 2. Use a Python script to convert this into the desired code:
>>
>> declare('XYZ_FOO', 0, "The foo property")
>> declare('XYZ_BAR', 1, "The bar property")
>> declare('XYZ_BAZ', 2, "reserved for future use")
>>
>> Note:
>>
>>  >>> s
>> 'XYZ_FOO 0 The foo property'
>>  >>> s.split(None, 2)
>> ['XYZ_FOO', '0', 'The foo property']
>
> Given that set of triples is constant, I would think about having the 
> Python script do the computation just once, instead of with every 
> inport. In other words, the script should *call* the declare function 
> and then write out the resulting set of dicts either to a .py or 
> pickle file.
>
> tjr
>
>
There have been lots of good suggestions in this thread.  Let me give 
you my take:

1) you shouldn't want to clutter up the global dictionary of your main 
processing module.  There's too much risk of getting a collision, either 
with the functions you write, or with some builtin.  That's especially 
true if you might later want to use a later version of that pdf file.  
Easiest solution for your purposes, make it a separate module.  Give it 
a name like defines, and in your main module, you use

import defines
print  defines.XYZ_FOO

And if that's too much typing, you can do:
import defines as I
print  I.XYZ_FOO

Next problem is to parse that pdf file.  One solution is to use a pdf 
library.  But another is to copy/paste it into a text file, and parse 
that.   Assuming it'll paste, and that the lines you want are 
recognizable (eg. they all begin as  #define), the parsing should be 
pretty easy.  The results of the parsing is a file  defines.py

Now, if the pdf ever changes, rerun your parsing program.  But don't run 
it every time your application runs.

If the pdf file were changing often, then I'd have a different answer:
2) define an empty class, just as a placeholder, and make one instance I
      Populate a class instance I with    setattrib() calls, but access 
it with direct syntax, same as our first example.


DaveA




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