ctree data

[Terry Reedy]

"Carl K" <carl at personnelware.com> wrote in message 
news:r4idnSn4-LNhttvbnZ2dnUVZ_uWlnZ2d at comcast.com...
|A friend needs to convert c-tree plus data to MySql.  I can to the "to 
MySql
| part, but need some help with the "from c-tree."  If I just wanted to get 
this
| done, I would hunt down the ODBC driver and use some MSy thing.  But I am 
trying
| to hone my Python skills,
| My searching around has come up with a few ways to use Python to read the 
data:
|
| 1. pull what I need from some other py code that uses c-tree:
|
| 
http://oltp-platform.cvs.sourceforge.net/oltp-platform/OLTPP/services/PythonScript/PythonTranslate.h?view=markup
| 
http://oltp-platform.cvs.sourceforge.net/oltp-platform/OLTPP/scripts/TestZipCodes.py?view=markup
|
|     12     a,b,c = ZipCode.Get()
|     13     print "Zip code is ", a
|     14     print "State is ", b
|     15     print "City is ", c
|
| I am sure this is what I want.  I just haven't figured out where to 
start.
|
| 2. "Pyrex"  to create Python bindings to C API with minimal C knowledge. 
I took
| C and did a few little utilities on my own in the 90's.  plus I can make 
a
| tarball.  today I am not sure I even qualify for "minimal."
|
| 3. the C API is present as a shared object (.so), use it from Python with
| ctypes.   I have no idea what that means.
[snip]

I personally would start with either 1 or 3, but probably 3 since the skill 
of using ctypes is transferable to other problems and I want to learn it 
anyway.  Ctypes is a foreign function interface (FFI) module.  It is new in 
the Python stdlib with 2.5 but has been around as a 3rd party module much 
longer.  With a specification of the C API in hand, you should be able to 
write Python functions that call functions in the shared library.  Ctypes 
handles the interconversion of Python and C datatypes and the calling 
details.

I would start with the simplest thing that you can verify working: open 
database, get some info that you can print, so you know you really opened 
it, and close database.

Terry Jan Reedy