supercollider-common 1:3.8.0~repack-2 / usr / share / SuperCollider / HelpSource / Classes / Pdefn.schelp

class:: Pdefn
summary:: non event stream reference definition
categories:: Libraries>JITLib>Patterns, Live Coding
related:: Classes/Pdef

description::
Pdefn provides an interface to its superclass link::Classes/PatternProxy::, keeping a reference to a stream that can be replaced while playing. One pattern may be used in many streams in different places. A change in the pattern definition propagates through all streams.

Pdef and Pdefn use separate global collections.

code::
Pdefn(key)	//returns the instance
Pdefn(key, pat)	//defines the pattern and returns the instance, like Pdef, Tdef and Ndef.
::

It is very similar to link::Classes/PatternProxy::.

Pdefn can be used to store value patterns globally (for strong::event patterns::, see link::Classes/Pdef::). Overview: link::Overviews/JITLib::

subsection::First Example

code::
s.boot;

Pdefn(\x, Pbrown(0, 6, 0.1, inf));
Pbind(\note, Pdefn(\x), \dur, 0.3).play;
Pbind(\note, Pdefn(\x), \dur, 0.1, \ctranspose, 15).play;
// now change the definition
Pdefn(\x, Pseq([0, 3, 5, 7, 9, 11], inf));
Pdefn(\x, Pseq([0, 3, 3, 7], inf) + Pseq([0, [0, 3], [0, 5, 7]], inf));
::

ClassMethods::

private::initClass

subsection::Creation

method::new
Store the pattern in a global dictionary under key, replacing its pattern with the new one. If the pattern is a strong::function::, Pdefn creates a link::Classes/Prout:: with this function, passing in the envir, if given(see below).

Using strong::*new(key):: you can access the pattern at that key (if none is given, a default silent event is created)

code::

// pattern as an argument
Pdefn(\x, Pseq([1, 2, 5, 6, 7], inf));
Pdefn(\x); // omitting the second argument, we can access the proxy
Pdefn(\x).asStream.nextN(20); // ... play one event stream
Pdefn(\x).source.postcs; // ... and inspect the event pattern itself.


// function as an argument, create a new pattern each time it is called
Pdefn(\x, { Pseq({ 10.rand } ! 8) });
Pn(Pdefn(\x)).asStream.nextN(16);

// the function is called in the incoming event as current environment, so parameters can be passed:
Pdef(\stut, { Pstutter(~stutter ? 1, ~pattern) }); // we use here a Pdef (not a Pdefn!)
Pdefn(\y, Pdef(\stut) <> (pattern: Pdefn(\x), stutter: Pseq([2, 2, 4, 3], inf))).asStream.nextN(16);

::

method::default
Default source, if none is given. The default is a Pattern that returns 1.0 (This is 1 and not 0 to avoid deadlocks when used as a duration pattern. In a sense, 1 is just as generic as 0).

method::removeAll
Remove all proxies from the global dictionary ( link::#*all::)

method::clear
Clear all proxies, setting their source to silence.

method::all
Set or return the environment ( link::Classes/IdentityDictionary:: ) that stores all Pdefns.

InstanceMethods::

private::prAdd

Examples::

subsection::Pdefn in expressions

code::
Pdefn(\c, Pdefn(\a) + Pdefn(\b));

t = Pdefn(\c).asStream; // create a stream from Pdefn(\c)

t.value; // default value for a Pdefn is 1, so that it is a good time value default.

Pdefn(\a, 100); // (re)define Pdefn(\a) as 100

t.value;

Pdefn(\b, Pseq([1, 2, 3], inf)); // (re)define Pdefn(\b) as Pseq([1, 2, 3], inf)

3.do { t.value.postln };

Pdefn(\c, Pdefn(\a) * Pdefn(\b) - Pdefn(\a)); // (re)define Pdefn(\c)

8.do { t.value.postln };

Pdefn(\a, Prand([1, 4, 2], inf)); // (re)define Pdefn(\a)
::

subsection::Embedding Pdefn in other patterns

code::
Pdefn(\x, Pseq([1, 2, 3], inf));

x = Pseq([0, 0, Pdefn(\x)], inf).asStream;

t = Task({ loop({ x.next.postln; 0.3.wait }) }).play;


Pdefn(\x, Pseq([55, 66, 77],inf));
Pdefn(\x, Pseq([55, 66, 77],1));

t.stop;



// Pdefn can be accessed in multiple streams

(
SynthDef("Pdefhelp", { arg out, freq, sustain=1, amp=1, pan;
	var env, u=1;
	env = EnvGen.kr(Env.perc(0.03, sustain), 1, doneAction:2);
	5.do { var d; d = exprand(0.01, 1); u = SinOsc.ar(d * 300, u, rrand(0.1,1.2) * d, 1) };
	Out.ar(out, Pan2.ar(SinOsc.ar(u + 1 * freq, 0, amp * env), pan));

}).add;
s.boot;
)

(
Pdefn(\deg, Pseq([0, 3, 2],inf));

Pset(\instrument, \Pdefhelp,
	Ppar([
		Pbind(\degree, Pdefn(\deg), \pan, -0.8),
		Pbind(\degree, Pdefn(\deg), \dur, 1/3, \pan, 0.8)
])
).play;
)

Pdefn(\deg, Prand([0, 3, [1s, 4]],inf));

Pdefn(\deg, Pn(Pshuf([0, 3, 2, 7, 6],2),inf));

(
Pdefn(\deg, Plazy { var pat;
	pat = [Pshuf([0, 3, 2, 7, 6],2), Pseries(0, 1, 11), Pseries(11, -1, 11)].choose;
	Pn(pat, inf)
});
)
::

subsection::Timing

When does the definition change?

If quant is set, the update is done at the next beat or whatever is specified:

code::
Pdefn(\deg).quant = 4;
Pdefn(\deg, Pn(Pseries(0, 1, 8),inf));

Pdefn(\deg).quant = nil; // activate immediately again

(
Pdefn(\deg, {
	loop {
	5.do { |i|
		#[1, 3, 4].choose.yield;
		#[5, 0, 12].choose.yield;
		#[14, 3, 4].choose.do { |j| (i % j).postln.yield };
	}
	}
})
)
::

subsection::update condition

In order to be able to switch to a new pattern under a certain condition, the instance variable strong::condition:: can be set to a function that returns a boolean. Value and a count index are passed to the function. The condition is always valid for the strong::next pattern:: inserted. For stuck conditions, the strong::reset:: message can be used.

As counting up (such as emphasis::"every nth event, a swap can happen"::) is a common task, there is a method for this, called strong::count(n)::.

code::
z = Pbind(\degree, Pdefn(\x, \), \dur, 0.25).play;
Pdefn(\x, Pseq((0..5), inf)).condition_({ |val, i| i.postln % 6 == 0 });
Pdefn(\x, Pseq((7..0), inf)).condition_({ |val, i| i.postln % 8 == 0 });


// the above is equvalent to:
Pdefn(\x, Pseq((7..0), inf)).count(8);
::

subsection::Reset

code::
// reset to change immediately:
Pdefn(\x).reset;

Pdefn(\x).stop;
::

subsection::Functions as arguments to Pdefn

code::
Pdefn(\deg, { loop { yield(0.1.rand.round(0.01) + [2, 3, 9].choose) } });

// equivalent to:

Pdefn(\deg, Prout { loop { yield(0.1.rand.round(0.01) + [2, 3, 9].choose) } });

// this is not exactly true, see below..
::

subsection::The (inner) environment

code::
// set() creates a local environment that overrides the outer currentEnvironment

Pdefn(\z).set(\a, 1, \b, 5);
(
Pdefn(\z, { |e|
	loop { yield((e.a + e.b) + 0.1.rand.round(0.01)) }
})
); // [1]

t = Pdefn(\z).asStream;

t.nextN(3);

(
Pdefn(\z, { |e|
	//(e.a + e.b) + 0.1.rand.round(0.01) 1
	Pseq([1, 2, e.a], 1)
})
);

Pdefn(\z, Pseq([1, 2, 3], 1));

e = Pdefn(\z).envir


Pdefn(\z).set(\a, 3);

t.next;

Pdefn(\z).set(\a, Pseq([1, 2, 3], inf));

t.reset;
t.nextN(3);

Pdefn(\z).envir; // post the envir



// if you want to keep using the currentEnvironment at the same time,
// assign the currentEnvironment to the envir's parent (or proto) field
// (this shouldn't be a proxy space of course.)

Pdefn(\z).envir.parent = currentEnvironment;
~a = 9;
~b = 10;

t.nextN(3);
::