class:: Pmulpre
summary:: multiplies with value of a key in event stream, before it is passed up
related:: Classes/Pmul, Classes/Pmulp
categories:: Streams-Patterns-Events>Patterns>Math

description::

Multiplies with a value in an event, strong::before it is passed up:: the stream. To multiply with the value after it has been passed down, use link::Classes/Pmul::.

code::
(
var a, b;
a = Pmulpre(\note, 2, Pbind(\note, Pseq([1, 2, 3])));
x = a.asStream;
9.do({ x.next(Event.default).postln; });
)
::

Pmulpre does not override incoming values:
code::
(
var a, b;
a = Pmulpre(\freq, 801, Pset(\freq, 500, Pbind(\dur, 0.2)));
x = a.asStream;
9.do({ x.next(Event.default).postln; });
)
::

ClassMethods::

method::new

argument::name

argument::value
can be a pattern or a stream. The resulting stream ends when that incoming stream ends.

argument::pattern

Examples::

code::
(
var a, b;
a = Pmulpre(\freq, Pseq([401, 801], 2), Pbind(\dur, 0.5));
x = a.asStream;
9.do({ x.next(Event.new).postln; });
)
::

code::
//sound example
(
SynthDef(\sinegrain,
	{ arg out=0, freq=440, sustain=0.02;
		var env;
		env = EnvGen.kr(Env.perc(0.001, sustain), 1, doneAction: Done.freeSelf);
		Out.ar(out, SinOsc.ar(freq, 0, env * 0.1))
	}).add;
)

(
a = Pbind(\dur, 0.5, \instrument, \sinegrain);
b = Pmulpre(\freq, Pseq([1, 2, 3], inf), a);
b.play;
)
::