19f43d27aa
The name of the mathematician is Sierpinski. * Serpinski => Sierpinski * Rename serp => sierp.
131 lines
4.2 KiB
Racket
131 lines
4.2 KiB
Racket
#lang scribble/doc
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@(require "common.rkt" (for-label "../value-turtles.rkt"))
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@title{Value Turtles}
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@defmodule[graphics/value-turtles]
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The value turtles are a variation on traditional turtles. Rather than
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having just a single window where each operation changes the state of
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that window, in the @racket[graphics/value-turtles] library, the
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entire turtles window is treated as a value. This means that each of
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the primitive operations accepts, in addition to the usual arguments,
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a turtles-window value; instead of returning nothing, each returns a
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turtles-window value.
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@defproc[(turtles [width real?]
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[height real?]
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[init-x real? (/ width 2)]
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[init-y real? (/ height 2)]
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[init-angle real? 0])
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turtles?]{
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Creates a new turtles window with the given @racket[width] and
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@racket[height]. The remaining arguments specify position of the
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initial turtle and the direction in radians (where @racket[0] is to
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the right).}
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@defproc[(turtles? [v any/c]) boolean?]{
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Determines if @racket[v] is a turtles drawing.
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}
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@defproc[(move [n real?] [turtles turtles?]) turtles?]{
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Moves the turtle @racket[n] pixels, returning a new turtles window.}
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@defproc[(draw [n real?] [turtles turtles?]) turtles?]{
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Moves the turtle @racket[n] pixels and draws a line along the path,
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returning a new turtles window.}
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@defproc[(erase [n real?] [turtles turtles?]) turtles?]{
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Moves the turtle @racket[n] pixels and erases a line along the path,
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returning a new turtles window.}
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@deftogether[(
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@defproc[(move-offset [h real?] [v real?] [turtles turtles?]) turtles?]
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@defproc[(draw-offset [h real?] [v real?] [turtles turtles?]) turtles?]
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@defproc[(erase-offset [h real?] [v real?] [turtles turtles?]) turtles?]
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)]{
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Like @racket[move], @racket[draw], and @racket[erase], but using a
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horizontal and vertical offset from the turtle's current position.}
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@defproc[(turn [theta real?] [turtles turtles?]) turtles?]{
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Turns the turtle @racket[theta] degrees counter-clockwise, returning a
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new turtles window.}
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@defproc[(turn/radians [theta real?] [turtles turtles?]) turtles?]{
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Turns the turtle @racket[theta] radians counter-clockwise, returning a
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new turtles window.}
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@defproc[(merge [turtles1 turtles?] [turtles2 turtles?]) turtles?]{
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The @racket[split] and @racket[tprompt] forms provided by
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@racketmodname[graphics/turtles] aren't needed for
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@racketmodname[graphics/value-turtles], since the turtles window is a
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value.
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Instead, the @racket[merge] accepts two turtles windows and combines
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the state of the two turtles windows into a single window. The new
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window contains all of the turtles of the previous two windows, but
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only the line drawings of the first turtles argument.}
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@defproc[(clean [turtles turtles?]) turtles?]{
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Produces a turtles like @racket[turtles], but with only a single
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turtle, positioned in the center.
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}
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@; ----------------------------------------
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@section[#:tag "value-examples"]{Examples}
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@defmodule[graphics/value-turtles-examples]
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The @racketmodname[graphics/turtle-examples] library's source is meant
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to be read, but it also exports the following examples.
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@defproc[(radial-turtles [n exact-nonnegative-integer?] [turtles turtles?]) turtles?]{
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Places @math{2^n} turtles spaced evenly pointing radially outward.}
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@defproc[(spaced-turtles [n exact-nonnegative-integer?] [turtles turtles?]) turtles?]{
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Places @math{2^n} turtles evenly spaced in a line and pointing in the
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same direction as the original turtle.}
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@defproc[(neato [turtles turtles?]) turtles?]{
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As the name says...
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}
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@defproc[(regular-poly [sides exact-nonnegative-integer?]
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[radius real?]
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[turtles turtles?])
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turtles?]{
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Draws a regular poly centered at the turtle with @racket[sides] sides
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and with radius @racket[radius].}
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@defproc[(regular-polys [n exact-nonnegative-integer?]
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[s any/c]
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[turtles turtles?])
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turtles?]{
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Draws @racket[n] regular polys each with @racket[n] sides centered at
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the turtle.}
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@defproc[(spokes [turtles turtles?]) turtles?]{
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Draws some spokes, using @racket[radial-turtles] and
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@racket[spaced-turtles].}
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@defproc[(spyro-gyra [turtles turtles?]) turtles?]{
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Draws a spyro-grya reminiscent shape.}
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