rsc3/doc-schelp/HelpSource/Classes/Pcollect.scrbl

59 lines
1.1 KiB
Racket

#lang scribble/manual
@(require (for-label racket))
@title{Pcollect}
Apply a function to a pattern@section{categories}
Streams-Patterns-Events>Patterns>Filter
@section{related}
Classes/Pselect, Classes/Preject
@section{description}
Modifies each value by passing it to the function.
@section{classmethods}
@section{method}
new
@section{argument}
func
A link::Classes/Function::. Receives values from
@racketblock[pattern::.
]
@section{argument}
pattern
A link::Classes/Pattern::.
@section{examples}
@racketblock[
(
a = Pcollect( { |item| item * 3 }, Pseq( #[ 1, 2, 3 ], inf ) );
x = a.asStream;
9.do( { x.next.postln; } );
)
::
The message ]
@racketblock[collect:: returns a Pcollect when passed to a pattern. Note that because the pattern is converted to a link::Classes/Stream:: (more precisely a link::Classes/FuncStream::) the collect function is evaluated for one item each time the message ]
@racketblock[next:: is passed.
]
@racketblock[
(
a = Pseq( #[ 1, 2, 3 ], inf ).collect( { arg item; item * 3 } );
a.postln;
x = a.asStream;
9.do( { x.next.postln; } );
)
::
]