The initial version of ObjectiveMax, version 0.1, has been released over on the project site: http://code.google.com/p/objectivemax/

ObjectiveMax is a framework for creating objects in Objective-C for Cycling ‘74’s Max/MSP. It makes for a super easy way to create objects. For example, this is what the audio perform method looks like for an object doing the same thing as the +~ object in MSP:

- (t_max_err) processAudioWithInput:(MaxAudioSignal *)signals_in 
                          andOutput:(MaxAudioSignal *)signals_out
{
    short    vs = signals_in->vs;
    float    *in1 = signals_in->vectors[0];
    float    *in2 = signals_in->vectors[1];
    float    *out = signals_out->vectors[0];

    while(vs--){
        if(in2)
            operandAttribute = *in2++;
        *out++ = *in1++ + operandAttribute;
    }

    return MAX_ERR_NONE;
}

That’t all there is to make the object handle audio. Everything else that you would normally do in a C external (call the init dsp function in main, create a dsp method, etc.) is all automatic and behind the scenes.

If you want your object to handle a float message in Max, all you do is write a float method. Like this:

- (t_max_err) floatMessage:(double)value
{
    operandAttribute = value;
    return MAX_ERR_NONE;
}

The documentation is currently weak at best. There really needs to be a tutorial or something. This is an open-source project though, so perhaps someone will write one and contribute it to the project!