Re: [Pyobjc-dev] Find By Content

[Bob I. <bo...@re...>]

On Nov 14, 2003, at 4:32 PM, Pierce T. Wetter III wrote:

> On Friday, November 14, 2003, at 02:17 PM, Bob Ippolito wrote:
>
>> On Nov 14, 2003, at 3:43 PM, Dethe Elza wrote:
>>
>>> I am trying to get started using PyObjC.  What I'm interested in is  
>>> creating a command-line search tool using the Find By Content API,  
>>> which is in the ApplicationServices framework.  But I haven't been  
>>> able to figure out how to bootstrap far enough to find the API calls  
>>> from Python.
>>>
>>> Is the ApplicationServices framework already exposed by PyObjC?
>>>
>>> If not, how do I wrap it?  I've tried to follow the instructions  
>>> here: http://pyobjc.sourceforge.net/doc/wrapping.php, but haven't  
>>> had luck with it.
>>
>> ApplicationServices is not an Objective C framework, it can not be  
>> wrapped (directly) with PyObjC.
>>
>> As you can see by the documentation (  
>> http://developer.apple.com/documentation/Carbon/Reference/ 
>> Find_By_Content/index.html ), it's part of Carbon.  Carbon frameworks  
>> are a lot more work to wrap.  You'll want to use a tool like bgen,  
>> Pyrex, or SWIG .. or just write the bindings by hand (see "Extending  
>> and Embedding" and "Python/C API" at  
>> http://www.python.org/doc/current/ ).  It's not very fun.  There's  
>> also the option of writing an ObjC framework that wraps the C  
>> functions, but that doesn't look like it would make much sense in  
>> this case as the functions are not primarily CoreFoundation based.   
>> In short, it's not possible to wrap any APi that was available in Mac  
>> OS before OS X (and even several new APIs that are not ObjC) using  
>> PyObjC (directly).
>>
>> Currently, the only part of the Find by Content API that is wrapped  
>> are the error codes ;)  You're on your own here, properly wrapping  
>> about 50 functions and having them work correctly takes a good while  
>> even if you know the tools well.  You may want to ask on  
>> pythonmac-sig if anyone wants to volunteer to write it, or to help  
>> write it.
>
>  Actually, the easiest way to wrap a C framework for Python is to  
> write an Obj-C wrapper for it, IMHO.
>
>  That's what I've been doing.
>
>  Often you can find someone else who's done the work for you...

It really depends.  It was easy for me to wrap SystemConfiguration with  
ObjC, because SystemConfiguration was full of CoreFoundation types (as  
arguments and return values) that are transparently bridged to  
Foundation types.  Something from Carbon would be much more of a pain  
in the ass to wrap with ObjC.

-bob