class:: ProgramChangeResponder
summary:: allow functions to be registered to respond to MIDI program change events
related:: Classes/MIDIFunc, Classes/MIDIdef, Classes/MIDIResponder, Classes/CCResponder
categories:: External Control>MIDI

Description::
note:: SC 3.5 added the link::Classes/MIDIFunc:: and link::Classes/MIDIdef:: classes. These are faster, and aim to have a more convenient, logical and consistent interface, which shares a common design with link::Classes/OSCFunc:: and link::Classes/OSCdef::. They also provide support for all MIDI message types.::
ClassMethods::

method::new

argument::function
A link::Classes/Function:: to be evaluated. Arguments passed to the function are: src, chan, value.

argument::src
The src number may be the system UID (obtained from code:: MIDIClient.sources[index].uid ::) or the index of the source in the code:: MIDIClient.sources :: array. nil matches all.

argument::chan
An link::Classes/Integer:: between 0 and 15 that selects which MIDI channel to match. nil matches all. May also be a link::Classes/Function:: which will be evaluated to determine the match. eg: { |val| val < 2 }

argument::value
An link::Classes/Integer:: between 0 and 127 that selects which program change number to match. nil matches all. May also be a link::Classes/Function:: which will be evaluated to determine the match. eg: { |val| val >= 4 }

argument::install
If true, then if the midi event is matched, cease testing any further responders. Note that doing this will prevent any other responders of this type from responding, including ones added behind the scenes in classes. Note also that this functionality is sensitive to the order in which responders are added.

Examples::

code::
(
	c = ProgramChangeResponder({ |src,chan,val|
		[src,chan,val].postln;
		},
		nil, // any source
		nil, // any channel
		nil // any value
	)
)

c.remove
::

code::
(
	c = ProgramChangeResponder({ |src,chan,val|
		[src,chan,val].postln;
		},
		nil, // any source
		nil, // any channel
		(50..60) // within this value range
	)
)

c.remove
::
