rsc3/doc-schelp/HelpSource/Classes/Pchain.schelp

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class:: Pchain
summary:: pass values from stream to stream
related:: Classes/Pbindf
categories:: Streams-Patterns-Events>Patterns>Composition
description::
definitionList::
## Pchain(pattern1, pattern2, ... patternN) || pattern1 <- pattern2 <- ...patternN
::
Values produced by the stream of strong::pattern2:: are used as inval to the stream of strong::pattern1::. Therefore pattern1 overrides (or filters) the output of pattern2, and so forth. This is an equivalent to the composite pattern: emphasis::pattern1 <> pattern2 <> ... patternN::
ClassMethods::
method::new
argument:: ... patterns
The patterns to be chained up.
InstanceMethods::
method::<>
Add another pattern to the chain.
Examples::
code::
(
Pchain(
Pbind(\detune, Pseq([-30, 0, 40], inf), \dur, Prand([0.2, 0.4], inf)),
Pbind(\degree, Pseq([1, 2, 3], inf), \dur, 1)
).trace.play;
)
// also events can be used directly:
(
Pchain(
Pbind(\degree, Pseq([1, 2, 3], inf)),
(detune: [0, 4])
).trace.play;
)
// compose some more complicated patterns:
(
var a, b;
a = Prand([
Pbind(\degree, Pseq([0, 1, 3, 5, 6])),
Pbind(\dur, Pshuf([0.4, 0.3, 0.3]), \degree, Pseq([3, -1]))
], inf);
b = Prand([
Pbind(\ctranspose, Pn(1, 4)),
Pbind(\mtranspose, Pn(2, 7))
], inf);
c = Prand([
Pbind(\detune, Pfuncn( { [0, 10.0].rand }, 5), \legato, 0.2, \dur, 0.2),
Pbind(\legato, Pseq([0.2, 0.5, 1.5], 2), \dur, 0.3)
], inf);
Pchain(a, b, c).trace.play;
)
::
section::pattern composition
pattern <> pattern <> pattern
code::
// implicitly, the composition operator <> returns a Pchain when applied to a pattern.
// so that a <> b creates a Pchain (a, b).
// as seen above, in Pchain(a, b), a specifies (and overrides) b: b is the input to a.
// the above example is equivalent to:
(Pbind(\degree, Pseq([1, 2, 3], inf)) <> (detune: [0, 4])).trace.play;
(
a = Pbind(\degree, Pseq([1, 2, 3], inf), \dur, Prand([0.2, 0.4], inf));
b = Pbind(\detune, Pseq([-30, 0, [0, 40]], inf), \dur, 0.1);
c = b <> a;
c.play; // see that the \dur key of a is overridden by b
)
// also value streams can be composed
(
a = Pfunc { |x| x + 1.33 };
b = Pfunc { |x| x * 3 };
c = Pseries(1, 2, inf);
)
// post some values from the composite streams:
t = (a <> b).asStream;
10.do { t.value(10).postln };
t = (a <> b <> c).asStream;
10.do { t.value(10).postln };
t = (b <> c <> a).asStream;
10.do { t.value(10).postln };
::