Forums > Dev

list as inlet of a MSP object….how to?

May 9, 2009 | 6:33 pm

Hello everybody,
I have not understood how can I manage a list of float taken from an inlet of a MSP object. I studied the tutorial of SDK 5 and the examples but I have not found the answer ;-(

For example I just want to use a method that prints the numbers in the list. The list is just a message with the numbers and no other words.
I tryed to do this (but I do not if this is correct):

I declare a method:
void myobject_printlist(t_myobject *x, t_symbol *s, long argc, t_atom *argv);

In the main I write:
class_addmethod(c, (method)myobject_printlist, "list", A_GIMME, 0);

In the new method what have I to write in order to create an inlet that receive the list?
I can´t use floatin((t_pxobject *)x, 1);
So what have I to use?

Help!

Thanks in advance

Best regards

Luca


May 11, 2009 | 12:49 am

I’m only just learning this stuff myself, but, assuming your object is named "typetest", if you prototype

void typetest_list(t_typetest *x, t_symbol *msg, short argc, t_atom *argv);

then in your main declaration:

class_addmethod(c, (method)typetest_list, "list", A_GIMME, 0);

and finally, the method

void typetest_list(t_typetest *x, t_symbol *msg, short argc, t_atom *argv){
if(x->thru_on)
outlet_anything(x->outlet,msg,argc,argv);
}

will simply pass a list "1 2 3" to the outlet as a list "1 2 3"

If you want your list method to do something more complicated, assuming you have declared the outlets properly, the following will parse out the elements of the list according to type:

void typetest_list(t_typetest *x, t_symbol *msg, short argc, t_atom *argv){
if(x->thru_on) outlet_anything(x->outlet_thru,msg,argc,argv);
int i;
for(i=0; i
t_atom a = argv[i];
switch(argv[i].a_type){
case(A_LONG):
outlet_int(x->outlet_i,a.a_w.w_long);
break;

case(A_FLOAT):
outlet_float(x->outlet_f,a.a_w.w_float);
break;

case(A_SYM):
outlet_anything(x->outlet_s,a.a_w.w_sym,0,NULL);
break;
}
}
}

a complete .c file is attached.

Special thanks to John MacCallum and the CNMAT dev workshop last week Smile


May 11, 2009 | 10:59 am

Hi,
really really thanks!!!
My problem was that I had to use a proxy!!

Now it works.

All the best

Luca


May 11, 2009 | 10:48 pm

Hey,

I would recommend to use the atom_gettype, atom_getlong, and co from ext_obex.h instead of accessing the atom structure’s elements directly. IMHO, it’s more elegant, but the other advantage is that you don’t need to worry about how things are handled inside, but just use the methods to access to the specific items. Furthermore in the (highly unlikely) case that the atom structure changed, you wouldn’t have to change anything to your code to work because you don’t access items directly.


May 11, 2009 | 10:50 pm

Definitely!
I agree with you.

Cheers,

Luca


May 12, 2009 | 3:26 pm

yes, i agree, too. The atom_getlong et.al came up after this example Smile


May 12, 2009 | 6:34 pm

I’m sure they did. Just thought I would mention the "nice" way. It’s good to know both when you want to do some source code archeology anyway Wink


Viewing 7 posts - 1 through 7 (of 7 total)