69 lines
1.3 KiB
Racket
69 lines
1.3 KiB
Racket
#lang scribble/manual
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@(require (for-label racket))
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@title{Pif}
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Pattern-based conditional expression@section{related}
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Classes/Pwhile
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@section{categories}
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Streams-Patterns-Events>Patterns>Language Control
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@section{ClassMethods}
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@section{method}
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new
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@section{argument}
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condition
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A pattern or stream returning a link::Classes/Boolean:: value.
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@section{argument}
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iftrue
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This stream is evaluated if the link::Classes/Boolean:: is true.
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@section{argument}
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iffalse
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This stream is evaluated if the link::Classes/Boolean:: is false.
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@section{argument}
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default
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This value (not stream) is returned if "iftrue" or "iffalse" return nil at any time.
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@section{Examples}
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@racketblock[
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p = Pif(Pfunc({ 0.3.coin }), Pwhite(0, 9, inf), Pwhite(100, 109, inf)).asStream;
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p.nextN(20);
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// 7 of the 20 values, or roughly 30%, are in the 0-9 range:
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[ 105, 107, 107, 8, 100, 3, 105, 5, 107, 106, 1, 104, 8, 102, 102, 4, 108, 8, 109, 101 ]
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// sound example
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(
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SynthDef(\help_sinegrain,
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{ arg out=0, freq=440, sustain=0.05;
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var env;
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env = EnvGen.kr(Env.perc(0.01, sustain, 0.2), doneAction: Done.freeSelf);
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Out.ar(out, SinOsc.ar(freq, 0, env))
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}).add;
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)
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(
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var a;
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a = Pif(Pfunc({ 0.3.coin }), Pn(Pseries(0.5, 0.1, 10)), Pn(Pseries(6, -0.1, 10))).asStream;
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{
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loop {
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Synth(\help_sinegrain, [\freq, a.next * 600 + 300]);
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0.2.wait;
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}
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}.fork;
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)
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::
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]
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