Re: Wrapping C functions in Objective C proxy objects: naming convention?
Re: Wrapping C functions in Objective C proxy objects: naming convention?
- Subject: Re: Wrapping C functions in Objective C proxy objects: naming convention?
- From: "Austin Ziegler" <email@hidden>
- Date: Thu, 20 Nov 2008 07:58:44 -0500
On Thu, Nov 20, 2008 at 4:54 AM, Alexander Spohr <email@hidden> wrote:
> I'd go for #1.
> If you have an error in status, throw an exception.
>
> What is the reason to put those functions in a class anyway if you just
> mimic the c-function? Are you adding anything?
Yes, I am. The C function definition that I showed was actually just a
SOAP service definition. What my proxy object will be calling are
about three or four different C functions to make the SOAP call,
hiding that complexity from the programmer. (I could just use C++ and
have this code generated for me automatically, but this is also an
intellectual challenge to generate these Objective C wrappers that
mimic what the C++ code does.)
-austin
> Am 20.11.2008 um 06:27 schrieb Austin Ziegler:
>> For a project that I'm working on, I have a need to write a code
>> generator that will wrap certain kinds of C functions as Objective C
>> messages on an Objective C proxy. Because I don't ultimately control
>> the input, the parameters on the C functions may be poorly named. I'm
>> looking for advice on how one might make useful object message names
>> from C functions.
>>
>> The format of the functions in question is essentially like this[1]:
>>
>> int ns__add(double a, double b, double *result);
>> int ns__sub(double a, double b, double *result);
>> int ns__mul(double a, double b, double *result);
>> int ns__div(double a, double b, double *result);
>> int ns__pow(double a, double b, double *result);
>>
>> The int return is a status code; the result of the operation is in
>> double* result. If there's an error in the operation. (The status code
>> may be ignorable, in which case part of my following question is
>> answered; I'm still researching this part. I suspect that it is best
>> not ignored.)
>>
>> Anyway, the problem is how I should convert this function with poorly
>> named parameters into a proxy object and messages?
>>
>> The options that I've come up with (expressed in terms of use) follow.
>> They're all expressed in terms of an object ns__CalcProxy:
>>
>> ns__CalcProxy calc = [[ns__CalcProxy alloc] init];
>> double a, b, result;
>> int status;
>>
>> result = [calc addDoubleA:a withDoubleB:b]; // #1
>> result = [calc addDoubleA:a withDoubleB:b status:&status]; // #2
>> status = [calc addDoubleA:a withDoubleB:b returning:&result]; // #3
>>
>> The examples given here are simple; the items being returned may in
>> fact be pretty complex (and I'm planning on making it so that
>> structured parameters and return values may be passed in Objective C
>> proxies themselves).
>>
>> I really don't like the "addDoubleA:withDoubleB:" name, to be honest,
>> but what am I supposed to do with:
>>
>> struct ns1__ludcmpResponse {matrix *a; ivector *i; xsd__double d;};
>> int ns1__ludcmp(matrix *a, struct ns1__ludcmpResponse** result);
>>
>> Like I said; I don't really have any control over the names of the
>> parameters, more's the pity.
>>
>> -austin
>> [1] Actually, they're more like this:
>> int soap_call_ns__add(struct soap *soap, const char *soap_endpoint,
>> const char *soap_action, double a, double b, double *result);
>> But there's enough information in there for me to extract the former
>> to use as a proxy function.
>> --
>> Austin Ziegler * email@hidden * http://www.halostatue.ca/
>> * email@hidden * http://www.halostatue.ca/feed/
>> * email@hidden
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> ---
> Alexander Spohr
> Freeport & Soliversum
>
> Fax: +49 40 303 757 99
> Web: http://www.freeport.de/
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> ---
>
>
>
>
--
Austin Ziegler * email@hidden * http://www.halostatue.ca/
* email@hidden * http://www.halostatue.ca/feed/
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