Symbolic Notations

Arithmetic operators

Math operators apply to many classes, including arrays and other collections.

Using a basic math operator on a Symbol swallows the operation (returns the symbol)\symbol * 5 symbol

number + number

addition

number - number

subtraction

number * number

multiplication

number / number

division

number % number

modulo

number ** number

exponentiation

Bitwise arithmetic

number & number

bitwise and

number | number

bitwise or

number << number

bitwise left shift

number >> number

bitwise right shift

number +>> number

unsigned bitwise right shift

Logical operators

object == object

equivalence

object === object

identity

object != object

not equal to

object !== object

not identical to

Objects may be equivalent but not identical.[1, 2, 3] == [1, 2, 3] true [1, 2, 3] === [1, 2, 3] false // a and b are two different array instances with the same contents a = b = [1, 2, 3]; a === b; true // a and b are the same array instance

number < number

comparison (less than)

number <= number

comparison (less than or equal to)

number > number

comparison (greater than)

number >= number

comparison (greater than or equal to)

boolean && boolean

logical And

boolean || boolean

logical Or

When a function is the second operand, these operators perform short-circuiting (i.e., the function is executed only when its result would influence the result of the operation). This is recommended for speed.

With and: and or: second-argument functions will be inlined. If you use && or ||, no inlining will be done and performance will be slower.a = 1; a == 1 and: { "second condition".postln; [true, false].choose } second condition true a == 1 or: { "second condition".postln; [true, false].choose } true a != 1 and: { "second condition".postln; [true, false].choose } false a != 1 or: { "second condition".postln; [true, false].choose } second condition true

In this case, the second condition will cause an error if a is nil, because nil does not understand addition. a.notNil is a safeguard to ensure the second condition makes sense.a = nil; a.notNil and: { "second condition".postln; (a = a+1) < 5 } false a = 10; a.notNil and: { "second condition".postln; (a = a+1) < 5 } second condition false

Array and Collection operators

object ++ object

concatenation

collection +++ collection

lamination (see J concepts in SC)

collection @ index

collection/array indexing: .at(index) or [index]

collection @@ integer

collection/array indexing: .wrapAt(int)

collection @|@ integer

collection/array indexing: .foldAt(int)

collection |@| integer

collection/array indexing: .clipAt(int)

Set operators

set & set

intersection of two sets

set | set

union of two sets

setA - setB

difference of sets (elements of setA not found in setB)

set -- set

symmetric difference:(setA -- setB) == ((setA - setB) | (setB - setA))

Geometry operators

number @ number

make a Point of two numbersx @ y // returns: Point(x, y)

point @ point

make a Rect of two PointsPoint(left, top) @ Point(right, bottom) // returns: Rect(left, top, right-left, bottom-top)

ugen @ ugen

create a Point with two UGens

rect & rect

intersection of two rectangles

rect | rect

union of two rectangles (returns a Rect whose boundaries exactly encompass both Rects)

IOStream operators

stream << object

represent the object as a string and add to the stream. A common usage is with the Post class, to write output to the post window.Post << "Here is a random number: " << 20.rand << ".\n"; Here is a random number: 13.

stream <<* collection

add each item of the collection to the stream.Post << [0, 1, 2, 3] [ 0, 1, 2, 3 ] Post <<* [0, 1, 2, 3] 0, 1, 2, 3

stream <<< object

add the object's compile string to the stream.Post <<< "a string" "a string"

stream <<<* collection

add each item's compile string to the stream.

Conditional execution operators

object ? object

nil check (no .value)

object ?? function

nil check (.value, function is inlined) If the object is nil, the second expression's value will be used; otherwise, it will be the first object.a = [nil, 5]; 10.do({ (a.choose ? 20.rand).postln }); 10.do({ (a.choose ?? { 20.rand }).postln });

?? { } is generally recommended. ? always evaluates the second expression, even if its value will not be used. ?? evaluates the function conditionally (only when needed). If the function defines no variables, the function will be inlined for speed.

Especially useful when the absence of an object requires a new object to be created. In this example, it's critical that a new Slider not be created if the object was already passed in.f = { |slider, parent| slider = slider ?? { Slider.new(parent, Rect(0, 0, 100, 20)) }; slider.value_(0); };

If the first line inside the function instead readslider = slider ? Slider.new(parent, Rect(0, 0, 100, 20));

, a new slider would be created even if it is not needed, or used.

object !? function

execute function if object is not nil.a = [10, nil].choose; a !? { "ran func".postln }; // equivalent of: if (a.notNil) { "ran func".postln };

Used when an operation requires a variable not to be empty.f = { |a| a + 5 }; f.value // error: nil does not understand + f = { |a| a !? { a+5 } }; f.value nil // no error f.value(2) 7

Miscellaneous operators

object ! number

same as object.dup(number)15 ! 5 [ 15, 15, 15, 15, 15 ]

If the object is a function, it behaves like Array.fill(number, function).{ 10.rand } ! 5 [ 8, 9, 3, 8, 0 ]

object -> object

creates an Association, used in dictionaries.

expression <! expression

bypass value of second expression. This operator evaluates both expressions, and returns the value of the first.a = 0; 0 // a is incremented twice, but the return value (1) // comes from the first increment (0 + 1) (a = a + 1) <! (a = a + 1) 1 a // a's value reflects both increments 2

function <> function

function composition operator. This operator returns a new function, which evaluates the second function and passes the result to the first function.f = { |a| a * 5 } <> {|a| a + 2 }; f.(10); 60 // == (10+2) * 5

An array as argument is passed through the chain:f.([10, 75, 512]); [ 60, 385, 2570 ] // == ([10, 75, 512]+2) * 5

Symbolic notations to define literals/other objects

$

character prefix: "ABC".at(0) == $A

'' or \

define a literal Symbol : 'abc' === \abc

""

define a literal String : "SuperCollider is the best"

[item, item...]

define an Array containing given items

Set[item, item...]

define a Set -- any Collection class name can be used other than Set

#[item, item...]

define a literal Array

(a:1, b:2)

define an Event (same as Event[\a -> 1, \b -> 2])

` (backtick or backquote)

define a Ref : `1 == Ref(1), `(a+1) == Ref(a+1)

\

inside a string or symbol, escapes the next character"abc\"def\"ghi" abc"def"ghi 'abc\'def\'ghi' abc'def'ghi

\t

tab character

\n

newline character

\l

linefeed character

\r

carriage return character

\\

\ character

{ }

define an open function

#{ }

define a closed function

(_ * 2)

define a function { |a| a * 2 } (see Partial Application)

Argument definition

|a, b, c|

define function/method arguments

|a, b ... c|

define function/method arguments; arguments after a and b will be placed into c as an array

#a, b, c = myArray

assign consecutive elements of myArray to multiple variables

#a, b ... c = myArray

assign first two elements to a and b; the rest as an array into c

Where f is a function

f.( )

evaluate the function with the arguments in parentheses

f.(*argList)

evaluate the function with the arguments in an array

f.(anArgName: value)

keyword addressing of function or method argumentsf = { |a, b| a * b }; f.(2, 4); f.(*[2, 4]); f.(a: 2, b: 4);

SomeClass.[index]

Equivalent to SomeClass.at(index) -- Instr.at is a good example

myObject.method(*array)

call the method with the arguments in an array

obj1 method: obj2

same as obj1.method(obj2) or method(obj1, obj2). This works only with single-argument methods like binary operators.

Class and instance variable access

Inside a class definition (see Writing Classes ):{ classvar <a, // Define a class variable with a getter method (for outside access) >b, // Define a class variable with a setter method <>c; // Define a class variable with both a getter and setter method var <a, // Define an instance variable with a getter method (for outside access) >b, // Define an instance variable with a setter method <>c; // Define an instance variable with both a getter and setter method // methods go here ... }

These notations do not apply to variables defined within methods.

^someExpression

Inside a method definition: return the expression's value to the caller

instVar_ { }

define a setter for an instance variable

myObject.instVar = x;

invoke the setter: (myObject.instVar_(x); x)

Array series and indexing

(a..b)

produces an array consisting of consecutive integers from a to b

(a, b..c)

e.g.: (1, 3..9) produces [1, 3, 5, 7, 9]

(..b)

produces an array 0 through b

(a..)

not legal (no endpoint given)

a[i..j]

same as a.copySeries(i, j) (see ArrayedCollection: -copySeries)

a[i, j..k]

e.g.: a[1, 3..9] retrieves array elements 1, 3, 5, 7, 9

a[..j]

same as a.copySeries(0, j)

a[j..]

same as a.copySeries(i, a.size-1) (this is OK--Array is finite)

~

access an environment variable

~abc

compiles to \abc.envirGet

~abc = value

compiles to \abc.envirPut(value)

Adverbs to math operators

(see Adverbs for Binary Operators )

e.g.:[1, 2, 3] * [2, 3, 4] [ 2, 6, 12 ] [1, 2, 3] *.t [2, 3, 4] [ [ 2, 3, 4 ], [ 4, 6, 8 ], [ 6, 9, 12 ] ]

.s

output length is the shorter of the two arrays

.f

use folded indexing instead of wrapped indexing

.t

table-style

.x

cross (like table, except that the results of each operation are concatenated, not added as another dimension)

.0

operator depth (see J concepts in SC )

.1

etc.