134 lines
2.4 KiB
Racket
134 lines
2.4 KiB
Racket
#lang scribble/manual
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@(require (for-label racket))
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@title{if}
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@section{categories}
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Core, Common methods
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@section{related}
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Reference/Control-Structures
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conditional execution
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@section{method}
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if
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@section{section}
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example
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@racketblock[
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if ( [false, true].choose, // Boolean expression (chooses one at random)
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{ "expression was true".postln }, // true function
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{ "expression was false".postln } // false function
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)
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(
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var a = 1, z;
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z = if (a < 5, { 100 },{ 200 });
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z.postln;
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)
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::
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UGens can also use if
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the condition ugen is 0 / 1
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]
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@racketblock[
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(
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{
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if( LFNoise1.kr(1.0,0.5,0.5) , SinOsc.ar, Saw.ar )
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}.play
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)
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::
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]
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@section{section}
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optimization
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the functions will be inlined, which plucks the code from the functions and uses a more efficient jump statement.
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@racketblock[
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{
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if( 6 == 9,{
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"hello".postln;
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},{
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"hello".postln;
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})
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}.def.dumpByteCodes
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BYTECODES: (18)
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0 FE 06 PushPosInt 6
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2 FE 09 PushPosInt 9
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4 E6 SendSpecialBinaryArithMsg '=='
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5 F8 00 06 JumpIfFalse 6 (14)
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8 42 PushLiteral "hello"
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9 A1 00 SendMsg 'postln'
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11 FC 00 03 JumpFwd 3 (17)
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14 41 PushLiteral "hello"
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15 A1 00 SendMsg 'postln'
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17 F2 BlockReturn
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a FunctionDef in closed FunctionDef
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::
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failure to inline due to variable declarations
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]
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@racketblock[
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{
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if( 6 == 9,{
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var notHere;
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"hello".postln;
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},{
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"hello".postln;
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})
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}.def.dumpByteCodes
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WARNING: FunctionDef contains variable declarations and so will not be inlined.
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in file 'selected text'
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line 4 char 14 :
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var notHere;•
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"hello".postln;
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-----------------------------------
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BYTECODES: (12)
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0 FE 06 PushPosInt 6
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2 FE 09 PushPosInt 9
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4 E6 SendSpecialBinaryArithMsg '=='
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5 04 00 PushLiteralX instance of FunctionDef in closed FunctionDef
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7 04 01 PushLiteralX instance of FunctionDef in closed FunctionDef
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9 C3 0B SendSpecialMsg 'if'
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11 F2 BlockReturn
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a FunctionDef in closed FunctionDef
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::
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]
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@racketblock[
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{
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if( 6 == 9,{
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"hello".postln;
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},{
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"hello".postln;
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})
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}.def.dumpByteCodes
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BYTECODES: (18)
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0 FE 06 PushPosInt 6
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2 FE 09 PushPosInt 9
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4 E6 SendSpecialBinaryArithMsg '=='
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5 F8 00 06 JumpIfFalse 6 (14)
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8 42 PushLiteral "hello"
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9 A1 00 SendMsg 'postln'
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11 FC 00 03 JumpFwd 3 (17)
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14 41 PushLiteral "hello"
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15 A1 00 SendMsg 'postln'
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17 F2 BlockReturn
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a FunctionDef in closed FunctionDef
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::
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]
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